Johns Energy-Saving Blog

Come Check Out My New Website

2012-01-30T15:47:00.001-07:00

Come check out my new website:
Click here:
www.John Saves Energy.com

2011-12-31T10:05:00.003-07:00

Well, I’ll be! I’m in the newspaper.

Also, I am in the beginning stages of converting my blog over to my new website
www.johnsavesenergy.com

If you have an idea for an energy saving topic let me know.
John

2011 All-Electric Antelope Island Tour

2011-12-27T21:33:00.002-07:00

Several weeks ago I decided to take my truck to a place where (at least to my knowledge) no electric vehicle has driven to, on its own power before.

Antelope Island, Utah. In middle of nowhere in the Great Salt Lake there is a lone mountain that stands high out of the water. Antelope Island. Decades ago they built a 7 mile long causeway from Syracuse, UT, across the Great Salt Lake to Antelope Island. The island now has several miles of paved and un-paved roads.

I mapped out ahead of time the route I would take in my electric truck. I took the Interstate to Antelope drive and from there drove strait west until I reached the Lake shore. I drove the 7-mile causeway to the island and proceeded to drive around the island.

I took a wrong turn and ended up on top of a high vista looking out over the west shore side of the island. Backtracking, I headed into the direction I originally planed (to a farm-house 11 miles down the road. I knew this 5 mile wrong way turn would cost me in the end but for some reason I continued to the farm house anyway. Against the better judgment of the voices in my head, I kept going onward. I don’t know which is crazier, having voices in your head or not listening to them tell you that you are going to get stranded on an island without electricity while you are driving an electric truck.

I made it to the farm house and spent a while looking around.

As the sun was starting to set behind the mountain, it occurred to me that on the other side of the large island, and across the 7-mile causeway, there is a large gate that closes at sunset. “If that gate closes before I go under it, I am spending the night here”.

I started driving back the way I came. I made it back to the causeway but as I got about ½ way across, my battery pack began to show signs of being done for the evening. I could no longer maintain 50mph, 45, 40, 35. As the sun was quickly getting lower in the sky behind me, I squinted in vain trying to make out the toll shack and gate on the other end of the causeway. After what seemed like an eternity, I passed the shack and drove past the gate. “Whew!”, at least I will not be sleeping with coyotes tonight. Where I end up is another story”.

I did it! I am the first person to drive an all electric vehicle from land, across the causeway to Antelope Island and back again.
I let the truck battery pack rest for a few minutes in hopes of gaining some extra range.

I still had a good 15 or so miles to go before I made it back to my house. I thought about the route I took getting here and how it was not exactly a strait line. “If I cut through some neighborhoods, I may be able to shave 3 miles off my trip home”. Driving slowly on the shoulder, I managed to go another 6 miles before the truck battery was all the way dead. I pulled onto a dead-end street. OK, now what?

By this time, it was pretty dark outside. I went to the nearest door and rang the doorbell, “May I borrow a cup of electricity”? I asked.

The old lady at the door looked worried and confused. She directed me to a man across the street. He was kind enough to let me plug in for an hour.

As I waited for my truck to get some life back, I thought about the day's journey. It was an adventure to say the least.
I wrote a thank-you note to the kind, unknown citizen who lent me a dime’s worth of electricity. He had since gone back inside for the evening so I unplugged, left him my note and a dollar for his trouble of helping me.

One kilo-watt-hour only gives about 3 miles worth of range in my truck but letting the batteries sit for an hour must have helped too. I was able to drive the remaining 7 miles back to my house. Well, Almost.

As my batteries were beginning to show signs of being done just 2 miles from home, I approached the round-about. Not wanting to use my brakes for fear of wasting any precious momentum that I had acquired, I turned off, one turn early. This route was about the same distance as the next round-about exit but as took the turn, I remembered the large hill that this route included.

There was no way I would make it up that hill, not with the batteries in the condition that they were in. I drove up most of the hill before being forced to stop for a 5-minute battery rest. This time, even the motor controller was powering itself down due to low voltage. "It’s about time it reached a low voltage state.", I thought to myself.

Amazingly, the ATX power supply that provides power for my headlights and the all-important contactor relay managed to stay up without any complaints whatsoever. That’s a well-made piece of equipment.

It gave me an idea though. I turned off the headlights and to my surprise, the motor came back to life with a lethargic surge. Slowly, I was off again. Only ¼ mile remaining. I rolled into my cul-de-sac and started to go up the driveway. Denied! My truck would not roll up the gentile hill slope into my garage. I let it rest on final time before it lugged slowly up the incline and into its spot in the garage by the charging outlet. After 63 miles and a very long day, I’m home.

EV Winter Problems and Solutions

2011-12-18T09:34:00.004-07:00

Driving an electric vehicle, you have to be aware of the weather conditions. While I can comfortably drive the 40 mile round trip to work and back when it is warm outside, in the winter time, my batteries are not as cooperative. Cold batteries can reduce the normal range of an electric vehicle by 30% or more. I have gotten around this for the most part by insulating the batteries and insulating my garage (what a mess I made but it was worth it in the end).

Even with well below freezing temperatures outside, the garage stays a comfortable 43 degrees F. This also makes it extra pleasant when you have to go somewhere and the vehicles are already partially warmed up.

At the beginning of the week, after my truck has sat all weekend in the garage without any regular charging, the batteries are approaching 45 degrees. This doesn't cause too much problem on the way to work but after the truck has sat in the parking lot at work for 10 hours, the batteries have dropped even lower in temperature. The drive home on the first work day of the week is an anxious one. I watch the volt meter very closely. 120, 115, 110, 105 volts. Once the under-load voltage drops to 100 Volts, I know I have less than 2 miles of range before it's game over. At that point, I have to pull over and let the batteries rest for 10-15 minutes before I can slowly drive the rest of the way home.

Every other day of the week isn't a problem because charging the batteries up the night before also heats them to 75 degrees or so. That is sufficient so my truck can sit in the cold, exposed parking lot all day and the batteries only drop to 58 degrees or so. I am still able to make it home without any problems. But for me, that's not good enough.

Battery Warmer:

I bought some ice melting cable, (the kind you string on your roof to prevent ice dams and roof damage) and wrapped it around my batteries. If my batteries are not warm enough, I can plug in the warming cable. This allows me to warm up the batteries overnight without having to over-charge them to create heat. Eventually, I want to connect this cable up to a thermostat and wire it to the battery pack itself. At the cost of a couple miles in range, the batteries will maintain temperature all day at work and still have sufficient range that I can make it home.

Truck Bed Cover:

I originally wanted to build a super fancy, aerodynamic, teardrop shaped truck bed cover, but that would not be very practical. I want one that won't get in the way of me swinging by Home Depot on a whim for a couple sheets of OSB. I compromised for a quick and dirty flat cover. Using the last scraps of plastic, (from the sheet used for the air dam), I hastily built a cover that could withstand an 80 mph head wind (freeway driving conditions).

As luck would have it, I drove to work the next day during some of the worst winds that Davis County has seen in 20 years. As I drove southbound through Centerville, through the high wind corridor, the 90-103 mph east wind gusts made quick work of my truck bed cover, tearing half of it off. Watching electrical transformers light up the early morning sky while trying to avoid flying debris and rubberneckers looking at semi trucks that had flipped over on I-15, I somehow made it in to work.

Here is my sort-of-repaired bed cover. It does help reduce the wind drag quite a bit. Wind is not partial to ugliness, only form.

Reducing Cold Induced Friction:

I noticed in the winter time that on the way home from work, my current draw is higher than on the way in to work. I have dismissed it in the past assuming it is caused by a headwind or something.

I read that cold motor oil is thicker and will rob horsepower until the oil can heat up and reach its desired viscosity.

Another EV driver in the Salt Lake area suggested to me that transmission/gear oil is the same way. In a normal engine, the transmission heats up as the engine heats up. This is because the bell housing of a transmission is mechanically and thermal coupled to the engine. A hot engine will yield a hot transmission. Thick gear oil is specified so that when the engine warms up, the oil thins to its correct viscosity.

But in my truck, the electric motor doesn't get hot like in a gas engine. Thick oil will remain thick. I decided to replace the transmission and differential oil with thinner oil. It is anyone's guess what the negative long term effects will be of using thin motor oil as gear oil in a cool running electric vehicle. I am willing to give it a try.

Initial Results:

I started out by only replacing the differential oil before I drove my electric truck to work the next morning. To my surprise, it reduced my 55mph current draw by 5 amps (from 100 amps to 95 amps). For a large portion of my to-work commute, I was only pulling 75 amps at 55mph. I suspect I had a tailwind and some traffic corridor wind in my favor as well. But usually under these conditions the truck is pulling about 80 amps.

On my way home, I had so much battery capacity remaining, I began to question the gauges. After a recharge overnight, I was surprised that it only took 12.3KWh to charge back up. I usually need 13KWH or more to drive 40 miles. Replacing the 75W90 differential oil with 0W30 synthetic reduced my energy use from 325KWh/mile to 308KWh/mile. That's a 5% reduction in energy use. Wow! That is really surprising. I didn't expect it would make that much difference.

The thin oil in the rear differential made a huge improvement. What about the transmission oil?
That evening, I changed out the 75W90 oil in the manual transmission case with some 5W30 that I had on hand. I didn't have any more 0W30 synthetic. The next day, I drove to work without any problems. Keep in mind the weather inversion in the Salt Lake valley (ironically caused by engine exhaust) maintains a depressing cloud cover and keeps the air temperatures in the high 20's and low 30's F all day long. On the way home, there was a 10-14mph headwind that caused my truck to pull about 115 Amps (at 55mph) from the batteries. I was pleasantly surprised that I didn't have any range issues and made it all the way home comfortably.

I recharged my batteries that night, accidentally leaving them on for an extra couple hours. It only took 12.7KWh. Not bad for driving in a headwind half the time.

These are some really preliminary results so I must collect several more days worth of data.

Winter Tune-Up for Appliances and Your Home

2011-12-05T22:00:00.000-07:00

Winter time is an expensive time of year. Holiday shopping, family gets together, extended traveling. Why not save some green this year by lowering your winter utility bills.

Christmas Lights: LED Christmas lights are getting less expensive each season. Each year, I used to put up 4 strings of twenty-five 7-watt Italian Christmas bulbs on my roof. That’s 700 watts worth of Christmas lights on the house. The Christmas tree had almost 600 watts worth of lights on it. The tree lights were running an average of 10 hours a day and the roof lights were on 8 hours a night unless I forgot to turn them off. Weekends, the lights were on even longer. One month of electric Christmas cheer cost nearly $40 in electricity.

I have since upgraded to roof and tree to LED lights. Only now, the house has 14+ strands. The tree still has the same 10 or so strands on it. My holiday cheer has gone up with more lights burning, except now it only costs about $2 for the season. The LEDs paid for themselves in electrical savings alone after the 2nd season.

Remove Window Screens: Remove the south-facing window screens in the winter time. Doing this will increase the solar heating through these windows by 40%. On a cold, sunny winter day, open the blinds and curtains on the south side. On a particularly cold, sunny day, it was 10 degrees F outside my house and a toasty 74 degrees inside even though the furnace was only set to 69 degrees. Even after the sun set, it took a few more hours before the house cooled down to where the furnace had to kick on again.

Wash Windows: Cleaning the windows (inside and out) will also allow in more solar radiation, heating your home further.

Clean the glass on light fixtures and light bulbs: You will be amazed at how much more light your fixtures will emit when the dead insects are removed and the glass is cleaned. It will seem so bright, you might even want to replace the bulb with a lower wattage one, saving even more energy.

Cheryl calls all our vehicles and appliances zombies because they never die. I keep repairing them. Most of the time when an appliance dies, it was because it wasn’t maintained properly. The repair is usually an easy fix. You just need to be willing to tear into it and try to fix it. It’s dead anyway, what’s the risk in trying to bring it back to life?

Clean out the intake air vent on your hair drier. It’s gross but so what? Just remove all that sticky dust and hair that is clogging it all up. You will be so amazed at how much better the hair drier works. You may only need to run it on the low setting until it starts to clog up again. Cleaning it also makes it last longer. Better air flow keeps the heating element cooler and the exhaust air warmer.

While you are at it, remove the hair and string that is wrapped around the brush on your upright vacuum cleaner.

Clean out intake vents on your fireplace, refrigerator and overhead fans. And for heaven sakes, replace your furnace filter.

Just because you hear cold wind howling outside doesn't mean you have to feel it inside.

Insulating and air-sealing your home will really help reduce heating costs, especially when it is cold and windy. A perfectly insulated and sealed house with lots of south-facing windows would not even need a furnace in the winter months even when it is 0 F. outside. Daily solar radiation would be sufficient to heat the living space. There are however practical limitations in making this perfect home.

Make sure all windows and doors close properly and don’t leak air.

Buy foam inserts and install them behind all the exterior wall plates for plug sockets and light switches. It doesn’t take long to do, nor does it cost much but it makes a huge difference in reducing air leakage into your home. Your home will immediately feel less drafty.

I'm In The News

2011-11-28T10:35:00.000-07:00

We'll I'll be! My solar panels and electric truck made the news on Fox 13.

Here's a link showing the clip.

How Fun!

EV Charging Stations

2011-11-27T09:09:00.011-07:00

I recently read an article about the electric vehicle charging stations opening up in Salt Lake City. They are free (for now) to the public to use for charging their electric cars.
While I applaud the city of Salt Lake for their forward thinking, a large portion of the public opinion is against such things. They feel strongly that tax payer dollars (or pennies rather) should not be spent to pay for a portion of a few driver's transportation costs.
I was recently near Liberty park where one of these charging stations resides. While I had sufficient battery capacity to drive back home to Kaysville, I wanted to try one out so I knew what to expect in case the situation arose where I needed to plug in for a quick battery re-charge.

It was a first class thrill to have a guaranteed parking spot that refueled my truck while I played at the park. After 20 minutes and at the cost of 3 cents to the tax payers, I was back on the road.
By providing EV charging stations, the State of Utah is qualifying as a place where electric cars can be sold commercially on a much larger scale.
It's a chicken or the egg scenario. Commercial all-electric cars won't be sold in markets (like Utah) that don't have adequate charging stations. But nobody wants to support charging stations in Utah because there are not many electric cars here to utilize them.

Retail Businesses Can Help

A few weeks ago, I was driving home from work in my electric truck when I realized the old extension cord that I used earlier that day to re-charge my truck was faulty and my batteries weren't as full as planned. I found myself pulling off of the freeway 5 miles before my normal exit. I needed an extra 7 cents worth of electricity if I was to make it all the way home. Oh well, I need to buy a new extension cord at Home Depot anyway.

After receiving permission from the Home Depot store manager to plug in for an hour, I bought a new cord, plugged in and began re-charging the batteries. At 120 volts, it takes about 1 hour to build back an extra 5-miles. Three miles from the 1KWH of electricity and another 2 miles by just allowing the batteries to sit a while, rejuvenating them.
Hmm, what else do I need at Home Depot? It was during this hour of window shopping that I realized an invaluable, retail business, money-making principle. I am a captive audience and there is no such thing as a free lunch. Home Depot may be giving me 7 cents worth of electricity but they received much more from me. Not only am I that much more loyal and grateful to Home Depot for their service and hospitality, but I ended up spending an additional $50 on other stuff that I needed while I was waiting for my truck to re-charge.

Businesses that provide free EV charging stations will increase sales and make more money. This free service will in turn satisfy the charging infrastructure requirements for future EV markets. This is a Win-Win-Win situation for businesses, electric vehicles and the environment.

Bring on the Charging Stations!

Stay tuned for my post about the first ever All Electric road-trip to Antelope Island, Utah.
Also upcoming: One way distance records and longest all-electric distance record traveled in one day.

Solar Panels 1 Year Later: Happy Panelversary!!!

2011-11-15T22:23:00.002-07:00

Anyone wanting to get solar panels, my advice to you is to buy them ASAP. Now! If you live in the state of Utah, now is the best time in the history of the state to buy solar. If someone said to you, "Buy these solar panels for $22,000 and I'll pay you back $25,000, would you do it? Well this is exactly what is going on in Utah right now. Not only will you receive a 30% federal tax credit and $2000 state tax rebate, you can also qualify for up to 25% state energy rebate. If you have Rocky Mountain power, you will also qualify for up to a $2/watt rebate. With all these programs added together, you would actually end up with free solar panels and money in your pocket. It's up to you.
~~~~~~
It has been 1 year since I first installed solar panels on the house and tied them to the electric grid. In one year’s time, the panels have produced 8600 Kilowatt-hours or about $850 worth of electricity. Even though that is about 1000KWH less than what I estimated my panels would produce in a year, this energy production has been more than sufficient to supply my entire house with all of its electricity needs.

Until recently, I had a 2 month credit built up with the power company of excess energy that my solar panels generated and fed back into the grid. In September, I started exclusively driving my newly converted all-electric pickup truck. With my 40 mile commute requiring 12-14KWH of electrical energy, my credit with the power company was depleted 1 month later.

1 year ago, today, the power meter on the house was installed and set to 000000 KWH. Today, 1 year later it reads 000980 KWH. I was hoping to have it roll all the way back to 000000 by this date. I attribute the excess consumption to the electric truck, and an unusually wet and cloudy weather this year that prevented the solar energy yield from being as high.

I am driving the truck more than I thought I would. I love driving it so much, I find myself volunteering for errands that normally my wife would be doing in her minivan. Having driven the truck over 2100 miles so far, an extra 682KWH of energy has been extracted from my solar panels and the grid. If the cost of never having to pay for gas again is being unable to zero out the power meter each year then so be it.

Still, I would like to make my house and electric vehicle even more efficient so that my family can maintain our current standard of living and still zero out the meter. How cool would that be?

House consumption could be further reduced with additional insulation in the basement, attic and additional summer shading on all south facing windows.

Truck consumption could be further reduced by making the truck lighter and more aerodynamic.

Here is an example of an aero-cap; something I have yet to do on my own truck.

In a few years when my heavy, cheap lead-acid battery pack reaches the end of its life, I want to replace it with a lithium-ion pack. This will reduce the weight of the truck by nearly 800lbs. My 40 mile commute would only require 8KWH instead of 12KWH. The truck would also have better acceleration and extended range.

Resolving Overheating Issues

2011-10-26T18:16:00.173-06:00

I have started driving on the highway in 4th or even 5th gear instead of 3rd. This reduces the engine noise and transmission vibration so much that now I only hear the wind and other cars when I am cruising down the road at 70mph. The only problem with driving at a lower RPM on the electric motor is now my previous fixes to the controller overheating issue are no longer sufficient.

The controller has a fancy circuit which at low RPM acts like a DC transformer. It takes a mere 100Amps from the battery and delivers 400 amps to the DC motor.

"Young lady, in this house we obey the laws of thermodynamics!" -- Homer Simpson

I assure you, no conservation of energy violations are going on here. Just a practical application of Maxwell's equations being put to good use.
The DC transformer-like feature allows the motor to still provide plenty of torque without putting excessive strain on the battery pack. I assume this is also why I am getting extended range lately. 64-miles on one charge is my new distance record.

I found an utterly massive heat-sink on eBay for a mere $64 delivered. Weighing in at 17 lbs, this aluminum behemoth would probably keep hell itself at a constant 74 degrees.

After swapping out the 4 lb heat-sink for this much larger one, I have yet to hear one complaint out of the motor controller regarding temperature issues. With this improvement, the next weak link in my electric truck is the massive 11 inch diameter, 178 lb Kostov DC motor itself. It will get pretty warm after 20 minutes of extreme, hard driving. I now consider the overheating issue resolved.

Battery Charger 2.0

I beefed up the wiring in my home-made battery charger and also added better capacitors that have a lower ESR (series resistance that robs power, making things get hot). Before I made these changes, the charger could deliver up to 18 amps at 120 Volts and charge up the battery pack in 12-15 hours. Now it draws 30 amps at 240 volts and will charge up the battery pack in 5-7 hours.
Now I can come home after working late, plug in for an hour to add a quick 8 miles to the range of the truck, run a few errands in the evening, drive out to see a movie, come back home at 10PM, plug in all night and by 5AM, the truck has a full charge, ready to take me the 40 miles back and forth to work. Nice!

People of the world! Why aren’t we all driving electric cars? They are efficient, quiet, non-polluting, cheap to operate/maintain and super fun to drive.

Automakers of the World! Why aren’t you mass producing electric cars. Quit focusing on $45K - $100K custom cars and start cranking out the electrics as if you’re making Model T’s. If you build them we will buy them.

Oil Companies of the World! Your days in the fuel business are numbered. The only oil you’ll be selling will be for making molded, plastic seats.

OK, enough of the soap box! Where was I? Oh yeah! Battery chargers.

My capacitive battery charger is still not perfected but it's a whole lot better. I have not as of yet added any overcharge protection because overcharging lead acid batteries occasionally, brings all cells back to the same level and equal playing field. By using a capacitive, pulsating DC charger, the batteries are also desulfated and reconditioned.
Most of the time I can schedule it into my day to plug in and manually unplug before I leave, but yesterday was a weird exception where I plugged in later in the evening. By the time I went to bed 4 hours later, the battery pack was only 70% charged. I didn't want to leave it on all night because 10 hours would overcharge things too much, heating the batteries unnecessarily and waste power. I plugged in to 120 volts for the rest of the night. The battery pack ended up not getting a good enough charge and I almost didn't make it back home after driving 18 miles on the freeway with a 20mph headwind.
I still have some work to do before I will be satisfied with the charger, but it's not bad for a home-made charger. I am amazed at how simple the capacitive charging circuit really is. 2 components: A capacitor (made of several caps actually) and a bridge rectifier. It cost me about $50 for eight large surplus 50uF 440VAC capacitors at NPS and a couple bucks to my good man in Hong Kong for the 50 Amp bridge rectifier. I am also using the hell-freezer heat-sink for the rectifier as well.
Update: 10/28/2011 Don't expect cheap semiconductors from Hong Kong to last more than a few days. The 50Amp 1000 Volt bridge rectifier went off like a firecracker. I am suspecting the 1000 Volt component was counterfeit and was more likely a 100 Volt one. The 2nd one I bought as a backup only lasted about 30 seconds before it started making crackling noises and shorting out internally. I replaced it with my original, non-counterfeit rectifier. It runs slightly warmer and less spectacularly.

The down side to the capacitive charge circuit is the power factor is not very good. With a power factor of 1, it would be possible at 240 Volts and 30 Amps to draw 7200 Watts. My circuit, with it's power factor of only 0.33, pulls nearly 30 amps at the beginning of the charge cycle but only delivers 2500 watts. A far cry from 7200 watts the circuit is capable of providing. Hmmmm.
Remember, even though I am pulling 7200 Volt-Amps from the power outlet, I am only paying for 2500 watts. Even my solar panels only have to cough up 2500 watts. We must be vigilant against the trickery of power factor.

Update: 10/30/2011:

Warning! Dangerous and Free Engineering Advice:
If you are interested, here is the schematic to my simple charging circuit. I didn't invent this. A few months ago, I was about to spend $700 on a fancy commercial battery charger when a buddy of mine at Wilderness EV told me about this circuit. USE AT YOUR OWN RISK!

With the correct components, (and large enough wire and electrical infrastructure), you could potentially build a 6 minute battery charger. How cool would that be?

Make sure the capacitor(s) you end up choosing are bipolar. Hint: Most electrolytic ones are not bipolar and when connected up to AC will act more like an M-80 firecracker than capacitor. The large silver capacitors that accompany motors are perfect for this application. I have found that the larger the capacitor (physical size) the cooler it will operate and less likely it is to overheat. Try not to use the big blue capacitors from Hong Kong with the wire pigtails. They have too high of ESR and in this application, will over-heat, dry out and quit working in a couple weeks.
A crude rule-of-thumb is to use 25uF for each Amp of charging current you want to deliver to the battery pack.
Monitor your battery voltage as it is charging and know ahead of time what voltage is considered a full charge.
Rule of thumb for flooded lead acid batteries:
80% charged is 2.38 volts per cell (142.8 Volts for a 120 Volt battery pack)
bubbling and gassing starts to occur at 80%.
100% charged is 2.58 volts per cell (154.8 Volts for a 120 Volt battery pack)
vigorous bubbling and lots of gassing occurs at 100%.

It would be advantageous to get yourself a lamp timer. It will keep your batteries from boiling away when you forget to unplug them after they are charged. A Kill-A-Watt meter is also a valuable tool as it will keep track of the energy that it takes to charge up your batteries. From that you can calculate how efficient your electric vehicle is. For example, a typical charge for me is about 13KWH. I drive 40 miles each day (13,000/40) so I end up using 325 watt-hours/mile. As Lord Kelvin once said, "If you can't measure it, you can't improve it." I highly recommend the Kill-A-Watt meter.

Electric Truck: Range is everything!

2011-10-20T19:48:00.007-06:00

Well, I managed to repair my odometer and speedometer. I found a blown diode. After replacing it with another one I had on hand, the gauges came back to life. Yeah!

I completed my pizza pan hubcaps and they are working out well.

Over the weekend, I threw the hubcaps on my Honda Accord (same rim size as my truck's tires) for a 640 mile journey to Southern Utah and back. They worked great and contributed to a 46mpg average fuel mileage. Not bad for driving 70mph the whole way. I have found that I suffer from helium foot. I tried to maintain 75mph but am so used to only going 55mph back and forth to work, my speed kept dropping.

I almost drove the whole trip on one tank of gas. We were running late coming back so I drove a little faster, hurting my mileage a bit. I chickened out and got some more gasoline just 32 miles from my home.

Still, not bad for $48 worth of gas (~7.5 cents per mile). What am I doing talking about gasoline? Granted it's an amazing fuel but I am trying to quit the stuff? I'm hooked. We all are!

Anyway, back to the Electric Truck. The hubcaps along with the newly painted grill blocking metal sheet, contributed to my new distance record of 64 all electric miles on a single charge.

I actually made it home no problem with 59 miles on the odometer. 59 is a crappy number to end on so I kept driving around the city until I reached 64 miles. Those last 3 miles were pretty rough though.

I completed the modifications to my battery charger so it can charge a depleted battery in only 7 hours instead of 13-14 hours. It now runs on 240 volts at 25-28Amps. This required me to upgrade the internal wiring from 14AWG to 10AWG since it was getting very hot with all that current flowing.
I put the battery charger to the test by driving 85 miles (spanning 2 quick charge cycles). I drove 15 miles, climbing a steep grade up a 1000 foot hill to the Bountiful Temple.

After returning back home, I only had time to plug in for 90 minutes before driving in to work (20 miles). After returning from work, (20 more miles), with a very depleted battery, I charged up for 3 hours before running a few evening errands (15 more miles). I plugged the truck into the charger late that evening. By 5AM the next morning, the battery was full and my truck was ready for me to take in to work again. Excellent!

My last crucial hurdle will be to solve the overheating issue that still plagues the slightly undersized motor speed controller.

Electric Truck: How's it working for ya?

2011-10-07T17:42:00.002-06:00

I have been driving my truck to work and back (40 miles) almost every day for the past 3 weeks. On some of those days I even made extra side trips, running errands along the way. I estimate my max range is now upwards of 50 miles. I have driven 46 miles on a single charge, (battery was down to 30%).

I got some fancy vinyl lettering to advertise my affinity for electron propulsion.

Now I get a lot of looks from other drivers on the road. I don’t want to give electric cars a bad rap so I tend to drive faster than I should so they can be impressed with my home-made wonder. This is a mistake though and I end up killing my range to where I am limping home the last 2 miles.

Work In Progress:
I am still having problems with excessive vibrations at high RPM. This is due to a slightly bent shaft on the transmission and a flywheel that keeps shifting on its key-way. I removed the motor (a few times now) in order to re-seat the flywheel. It fixes the problem initially but 120 miles later the vibration comes back. I have found that by shifting into 4th gear on the highway, the RPM is lower and the truck runs quiet as can be. While driving 60mph, the loudest noise I hear is the wind and other cars on the road. Most of the time I drive 50mph (while traveling on the 55mph Legacy Highway) to extend my range.

I added Volt and Amp Gauges to my instrument cluster. They provide valuable feedback to how my driving habits are affecting my battery pack and subsequent range.

While adding LED back-lights to the instrument cluster, I inadvertently shorted something out. Now I keep blowing a fuse that feeds the speedometer and tachometer. Arggg! I am still scratching my head on this one. In the mean time, I borrowed my wife’s GPS so I can know how fast I am going. I would really like to know at a glance how far I have driven though.
Even though my battery charger can deliver nearly 19 amps initially, as the battery pack charges, its internal resistance changes. The current flowing in steadily drops until it is only delivering 7 amps at the end of the cycle. I work a 10-hour day with a 27 minute commute each way. Often times, I work later or run an errand on the way home. I rarely have more than 12 hours from the time I come home to when I have to leave for work again.

A 12 hour period is not enough time to fully charge a depleted battery. At the beginning of the week, (after the battery has had a good weekend charge), I drive to work and back with no problems. After charging all night, the battery is only at 90%. The next day I again drive the 40 mile round trip and back with no incidents. By the last day of the week, my battery is only 80% charged by morning. I make it in to work just fine but on the way home, I run out of energy about 2 miles short. I pull off to the side and wait a few minutes for the battery pack to recover before slowly rolling the rest of the way home.

A lot of EV drivers will tell you that you can simply plug in and charge up anywhere there is an outlet. That may be true but I liken this kind of behavior to running out of gasoline near someone's home so you take a cup of gas from their lawn mower to get you back on your way. Who's going to miss 25 cents worth of gas or 3 cents worth of electricity? Instead of cheating my way home from work, I would rather work toward making my truck go farther, be more reliable, comfortable, convenient and simply take me the distance that I want it to go.

I am working on 2 options for a better battery charger. One that runs on 240V which will give me a full charge in under 5 hours and another that still runs on 120V but switches in more capacitors, increasing the current draw a couple hours into the charging cycle.

After driving at 55mph continuously on the highway for 15 miles with a 100+ amp draw, the motor speed controller starts to overheat. Even with the cooling fans I installed on it, I have to let off the throttle for about 5 seconds every couple miles to keep it from overheating. I added a plastic rain-gutter downspout as a duct directly to the heat-sink on the controller and it really helped a lot. I really need to mount the controller in a better location that it will receive more airflow and still be protected from the elements.

After covering up the grill with a piece of sheet metal. I took some crude measurements and my current draw (while driving sustained at 50mph) has dropped from 106 amps down to 100 amps.

Not much, but enough to justify investing more time into aerodynamic modifications. It just occurred to me that a 6 amp reduction is a 720 watt power savings. I could allocate that 720 watts towards cab heating during the winter time.

Extending the Range:

2011-09-29T19:57:00.001-06:00

In my home-made, all electric pickup truck, I have been able to get about 35 miles per charge driving around town. On the freeway, I am hard pressed to get 28 miles. This is discouraging considering my daily commute is 20 miles each way, 75% of which is driving on the freeway. I could ask if my place of employment would allow me to plug in and charge the batteries while at work, but that really doesn’t align well with my goal of self sufficiency and independence. Besides, my calculations show that I should be getting 50-75 miles per charge. What’s going on here?

After doing more reading online, I learned that I was not charging the battery pack all the way. My pack is 120 volts. 100% charge is 127 volts. I was charging it up to about 129 volts and calling it good. Come to find out, that is only about 80% charged. To fully charge a 12 volt lead acid battery, you need to get the voltage up to about 14.5 or 15.5 volts. Duh! For my 120 volt pack, I shouldn’t stop at 129 volts. I need to go all the way up to 150 volts or higher. I guess I knew this all along but hearing 1200 lbs of lead acid batteries bubbling as they entered the gassing stage made me a little nervous. Turns out, that is a normal part of charging lead acid batteries to 100%.

Charging all the way up to full made a huge improvement in my range, buying me an extra 8-10 miles. But a range of 36-38 miles still isn’t good enough.
Initially, I thought I may have a bad battery or maybe even Costco batteries are pieces of junk (The Jury is still out on that one). After not finding anything conclusive, I decided to take a different approach. Eliminate all sources of friction! REDUCE DRIVETRAIN, ROAD AND AIR RESISTANCE.

It’s all about the bearings:
I started by replacing the front wheel bearings because they are easy to do on a RWD truck. To my surprise, they extend the max range to over 40 miles. I actually drove 46 highway miles. That about killed the pack and it’s pretty scary driving on a busy interstate when you realize you can no longer go 55mph anymore. 55, 50, 45, 40 mph. Why must there be a hill before my exit? Move over onto the shoulder. 35 mph, 30. Somehow I made it to my exit and onto the last main road before I arrived to my neighborhood. I pulled over to let the voltage in the battery pack recover. If you let a dead battery sit for several minutes, it will recover slightly and allow you to drive a couple more miles.

I managed to drive the truck over one last hill before rolling over the other side and into my neighborhood. Home at last. I don’t ever want to do that again and neither does my battery pack. At least now I know the limitations.

After giving the truck’s battery pack a very thorough charge overnight, I drove it to the tire store and had them replace the original tires with low rolling resistance variety. After I got the tires, I took the truck for a freeway speed test. My old speed record was 70 mph. I have tried to exceed 70 mph a few other times but each time, that is all she will do. With the new tires, I can drive 85 mph. Wow! A 15mph improvement. At first I didn’t believe it, thinking the tires were smaller and throwing off the speedometer or something. A second run with a GPS confirmed my new speed record was accurate.

Real Wheel Bearings:
Try as I might, I could not get the rear wheel bearings out. After 232,000 miles, metal on metal tend to meld into one piece. Even after over 100 attempts of using the redneck mechanic removal method (throwing down the axle shaft on some wood on the concrete as hard as you can), the bearings would not come out. I took the truck to Big-O Tires but sadly, they couldn’t get the rear wheel bearings out either. After a day of soaking the bearings in a corrosion blocker solution, they finally got them out, replacing them with bran new ones.

New distance record:
After charging the truck’s battery pack up to 100%, I drove it into work. Amazingly, this time, the 20 mile commute only depleted the battery pack to 80% state of charge. After sitting in the hot sun all day without charging, then driving 5 miles around running errands and then driving 20 miles to home at 55 mph, I pulled into my driveway with the battery pack at 40% state of charge. If I can drive 45 freeway miles with only using 60% of the battery, then maybe the battery would carry it further still. I estimate my max range is 50 miles but I don't want to confirm it lest I shorten the lifespan of my battery pack significantly.

Not Good Enough:
50 miles is fine for now but what happens when it gets really cold outside and the batteries have a 30% reduced capacity? Eventually I want to install a heater. Running a 1100 watt heater during my commute will reduce my range by another 3 miles.

If this truck is going to be my reliable commuter vehicle all year around, it needs to have a 70 mile range or better. That would also extend the life of my battery pack significantly on the days I only drive 40 miles depleting the pack to only 60%. So now what?
One word! AEROMODS!

Take it from my sexy Electric Truck's ugly sister the Tesla, Aerodynamics give you excellent range. Tesla has almost twice the battery capacity as my truck but over 4 times the range, (200 miles).

Electric Truck: Working out all the bugs

2011-09-29T19:38:00.001-06:00

I have now driven over 600 miles in my home-modified electric truck. I have made quite a few enhancements in some areas and am still at square one in others. I am still scratching my head why my range is not as good as I had hoped. I should be getting at least 50 miles per charge but I am only getting 28 highway miles per charge.

Costco batteries have a 75 amp rating of 115 minutes. When I am cruising on the highway at 50mph, my sustained current draw is about 120 amps. If I were to conservatively assume that my batteries will only last 60 minutes while pulling 120 amps, I should still be able to go 50 miles before they are discharged. For some reason, I am killing them early. Perhaps it's the periods when I am pulling more amps (like going up a hill or accelerating to freeway speed). But then there are also times when I am coasting down a hill or using the breaks where I am consuming no power. Hmmm.

I found one of my batteries had a lot lower voltage than the others. Even after equalizing all of them, when the truck was discharged to 30%, this one battery still showed very low voltage.
I also found several batteries had loose connections. While tightening them up, one of the posts ripped out of one of the batteries. I returned both batteries to Costco and got replacement ones. I also bought a battery load tester at Harbor Freight so I could determine if any more batteries were dead.

~~~~~~~~

I replaced my clutch plate, disk and thrust bearing. Now I have a working clutch. It is possible to shift without a clutch but with an electric motor, you have to be patient while the it spins down to a low enough RPM for the shifter to fall into the next higher gear. Now with a working clutch, I can shift nearly as fast as in a normal gas car.

I built a better motor mount after my first one broke at the welds. This 2nd mount uses a wide piece of flat steel to carry the weight of the motor and a Tee shaped piece of steel fastened to the firewall to keep the motor from twisting under high torque. This tee mount held the motor great but caused lots of transmission noise to resonate into the cab of the truck. I removed the tee and replaced it with a light weight, 1” wide metal strap screwed into the truck frame. No more resonance but now the strap is causing an annoying squeaking sound every time the motor tries to twist under torque, I learned that the twisting force on the motor is quite high and after 50 miles, it snapped a spot weld off of the strap.
Onto plan “D”. I welded 2 pieces of flat metal from the flat metal motor strap to the motor itself. Bingo! No more squeak and no more resonance. So far so good.

More recently, my flywheel has started making a lot of vibration at higher rpm's. It's kind of annoying and detracts from the quiet ride of the electric truck. I am waiting for the weekend to pull the engine back apart to have a look inside. That's the good thing about EVs. They are super easy to work on. One hour of work and the whole motor is out. 90 minutes later and everything is back together again. No oily grease, no seals to worry about, no fluids to drain, no filters, no fuss.

I replaced the 6 pack of large 50uF capacitors (that looked like a 6-pack of soda) with 4 smaller footprint 200uF capacitors.

This allowed me to have a lightweight on-board battery charger with higher charge current (7-19 Amps depending on the batteries state of charge) and smaller footprint size. They get kind of hot when the batteries are charging at the fastest 19Amp rate. I may have to install a small fan on them so they don't dry out.

I built a nice battery box to cover up all the batteries in the truck bed. It looks very unassuming until you peek inside.

Installing the Controller and Wiring

2011-09-10T15:28:00.003-06:00

A friend of mine gave me an old broken Curtis motor controller. I spent about $70 in parts and a couple hours replacing a dozen burnt out MOSFETs and power diodes. Sadly when I powered it on, it was still not operational. Oh well, it was worth the gamble. I forked over the money to buy a bran new one.

I proved out a concept that I read about on line where you modify a standard ATX computer power supply to take in 120 volts direct current and it will put out 12VDC. This will come in handy for powering all the 12 volt systems on the truck, (headlights, horn, radio, signals, relays, etc) without needing an extra 12 volt battery and additional charger.

I found a nice metal box at NPS for $8 to hold all the electrical parts. I drilled some holes, primed it, painted it white and mounted things up. Here it is being assembled in the mad science lab in my basement.

Here is the white box of parts that makes an electric truck tick. The big yellow thing that looks like a bomb is actually a capacitor array that I am using in a circuit for an experimental quick charger.

Trying It All Out:
On Friday Sept 2nd, 2011, I took the truck out for its maiden voyage. Initially, it drove great. I got it up to 40mph in 2nd gear. You can watch the video here.
There were a few bugs that I still needed to work out.

The welded motor mounts broke and had to be redesigned and rebuilt.
The motor speed controller needs a larger heat-sink. It overheated after 10 miles.
The clutch still doesn't work well, although it isn't needed in an EV.
The controller is a little sluggish at take off. I need to adjust it so I get more power while accelerating.

The next day, I came up with a better motor mount design where a metal strap supports the motor. You can see a day-time 2nd run here.

For more info on my electric truck, click here.

My electric truck can go up to 40mph in 2nd gear and up to 70mph in 3rd gear. It's range is still limited by the battery pack to about 40 miles. Before I can use it as a commuter truck, I need to break in the motor and the pack. I hope to have a 70 mile range by the time I finish tweaking everything.
To date, I have driven the truck over 120 miles. That's pretty cool considering all my electricity is generated by the power of the sun. In effect, this makes the truck solar powered.

Mounting The Batteries

2011-09-08T23:39:00.002-06:00

I needed a good way to hold 20 batteries securely in the truck without them bouncing all around.

I recently acquired a 230Amp welder off of ksl for $120. It even came with 40 lbs of welding rod and a welding hood. Nice!

I bought some angled and flat pieces of steel and starting cutting them up to make a battery tray that would hold 4 golf cart batteries in the front of the engine compartment.

I welded the pieces together, grinded them smooth, primed them and painted them. The angled edges hold the batteries fairly securely and prevent them from shifting around. A foam piece pressed against the hood of the truck finishes off the mount. Here's a video of me cutting and welding the battery tray.

I made two more battery trays, each can hold 8 batteries.

These larger trays mount in the front of the truck bed close to the cab.

I went to Costco to price out golf cart batteries. You can buy Trojan batteries for $149 each plus core charge. Costco had an equivalent capacity battery for only $79. I bought 14 of them on the spot and another 6 a week later. I found a 50 foot length of 00 welding cable on Ebay for $155, and built up all the cables needed to connect all 20 golf cart batteries in series.

My Electric Lawn Mower named Frankenstein:

2011-08-28T23:31:00.004-06:00

NPS has got to be one of my favorite places to find deals. Any store that sells nuts and bolts by weight is alright in my book. The other day, I happened across a bunch of small 6-volt rechargeable AGM batteries. Most of them were priced at $1.08 each. I have walked by this isle many times before but for some reason, today, I got an epiphany!
“Why not buy 20 of these little guys and string them all together into a 120 volt battery pack?”

Not only would it be a useful test bed for repairing the controller in my electric truck, but I could also modify my electric lawn mower to run on this battery pack instead of the heavy 12 volt deep cycle battery it currently uses.

My electric lawn mower runs great, but it is really heavy and a huge workout pushing it around my ½ acre yard each week. It has a large 115Amp-Hour, 12 volt battery that powers an inverter, that converts the 12 volt DC up to 120 volts AC, which is then rectified to high voltage DC, which then powers a DC motor. Each conversion has some efficiency loss.

In order to provide enough power to cut a thick green lawn, the 12 Volt battery has to be able to deliver 80 Amps continuously. There is a phenomenon in all batteries called “The Peukert effect” which causes a large battery delivering a lot of amps to act like a lower capacity battery.

For example, If you have a 100 Amp-hour battery, it will provide 1 amp continuously for 100 hours. But if that same battery tried to deliver 100 amps for 1 hour, it wouldn't last for 1 hour like we had hoped. Because of the Peukert effect, it may only last 40 minutes or so depending on the battery chemistry and age of the battery. CURSE YOU PEUKERT EFFECT!!!

A power inverter is a marvelous invention that converts 12 volts DC to 120 volts AC. Like everything else in the universe, work comes at a price. The inverter used on my lawn mower has about a 5-15% efficiency loss involved in the conversion. When the battery is ½ discharged, and while under load, the voltage drops below 10.5 volts and the inverter goes into a low voltage alarm state, shutting itself down. I can still have enough capacity to mow my lawn using this battery, but it bothers me that I am pushing around an extra 20 lbs of lead with no way of extracting the energy out of it.

In addition to the small losses of the bridge rectifier, at 157 Volts, the rectified DC doesn't run the motor at it's top speed either.

By using a 120 Volt DC battery pack, the current draw from the battery will be in the 2 to 5 Amp range, not 60-90 Amps like with a 12 volt battery. Also, because the 120 Volt DC is true DC, and not rectified, unfiltered DC, the motor will run at its full speed.
When the pack starts to discharge, instead of shutting off completely, the motor just spins a little bit slower.

A few months ago, I discussed how reducing resistive losses in the battery-inverter wiring allowed an extra 15 minutes of run-time before the inverter would shut down. That worked great but it's time I take it a step further.

Before:
12 Volt 115Amp-Hour deep-cycle battery. 50.2 lbs (plus inverter and wire 3.4 lbs).
12 X 115 = 1380 Watt-hours, or about 13 cents worth of electricity.

After:
Twenty 6 Volt 4.5Amp-Hour AGM batteries. 32.4 lbs
20 X 6 X 4.5 = 540 Watt-hours, or about 5 cents worth of electricity.

Both designs mow the lawn just fine, but for a manually propelled lawn mower, the 21.2 pound weight loss is a night and day difference. By pushing around less weight, it takes me less time to mow my lawn. 1 hour 5 minutes down to ~52 minutes.

EV Conversion Part 3 – Installing the Electric Motor:

2011-08-22T01:37:00.003-06:00

It’s amazing to me how simple a job can become when you have the right tools, good lighting and room to work.

Mandatory tools for an EV conversion job:

A place to perform the EV conversion, (for 200 hours or 2-6 months).

Impact wrench with deep walled sockets

Engine lift or cherry picker

Arc welder

Angle grinder

Chop Saw with metal blade

Drill press

Paint sprayer

Neoprene gloves x100 pair or more if you have OCD like me.

I bought a large DC electric motor and a generic adapter plate for connecting the motor to the transmission bell housing. I tested out the DC motor with a 12 volt battery to verify it works.

I lined up the motor with the adapter plate and clamped it in place.

Yeah, that kind of looks like blood but its spray paint from my first attempt at matching up the holes on the transmission bell housing. I drilled holes that matched my specific transmission.

I also had a shaft coupler machined that would match the shaft of the electric motor to the existing fly-wheel from the old engine. I still want the clutch intact for this EV conversion.

By grinding down a raspy metal file, I made a key for the motor shaft to lock into the coupler.

I used a couple extra hunks of metal from the old engine to secure the motor in place. I welded them to the motor and bolted them to the frame of the truck.

Wow! I now have a truck with an electric motor. I have to drive this around the block.

I connected up two 12-volt batteries in series and connected them to the motor with jumper cables. Using one end of a jumper cable for an instant on/off throttle control, ZAP, the truck came to life!

I drove it down the street a few of times at the screaming speed of 10mph. Check out this video clip of me test driving it here.

I really need to get more batteries and install the motor controller. Eventually this truck will drive at freeway speeds.

EV Conversion Part 2 – Making it look nice:

2011-08-18T19:43:00.003-06:00

After I pulled out all the parts from the internal combustion engine, I took a good look at the truck carcass that remained. It was dirty, rusty and kind of ugly. Since I was making such a large investment in a vehicle that I will be driving for the next 5-10 years, I decided to spend some extra time and make it look nice.

I washed off all the grease, pulled off the bed, sanded down the frame and primed all bare and rusty metal.

After that, I painted the frame a shiny black color. Once that paint had cured, I taped off all the glass and painted the truck with an air sprayer. It took 2 hours to tape everything off and only 15 minutes to spray the paint on.

I’m no expert in auto body paint but the paint job turned out very nice.

It was so easy, (relatively) that I now want to re-paint my 1992 Honda Accord.

They have so many wonderful hues and colors of paint now days. I believe the color of my car is called, “Fading, cracking vomit.” I’m going to re-paint it “Tree Hugger” green.

Electric Car Conversion Part 1 – The Donor Vehicle and The ICE Removal:

2011-08-17T19:46:00.003-06:00

In 2008, I bought an old Geo Metro for $1 for the purpose of converting it to an all electric car. I calculated it would have a 40 mile range and only cost me $3000 in parts. It would be the perfect commuter car, requiring only $0.67 cents in electric fuel to get me back and forth to work each day.

Unfortunately, my enthusiasm for the project faded when we moved to another house out of the range of the car's design.

Fast Forward 3 years:

My desire for an Electric Vehicle was rekindled by the announcement of the Nissan Leaf. But after nearly a year sitting on the waiting list, I opted to roll my own, again.

I have read that the an electric vehicle will have greater range if it can carry more batteries. It makes sense. More fuel = more range.

A Geo Metro has a light frame but has little room for extra weight. A pickup truck is relatively lightweight but has a stronger frame that can handle additional battery weight.

In June 2011, I acquired a 1992 Toyota Pickup Truck. Although the mileage was high, it was in good cosmetic condition.

I ripped out all the “unnecessary” parts. The internal combustion engine, radiator, gas tank and the exhaust system.

This lightened the truck weight by 500 lbs and freed up a lot of room in the engine compartment for an electric motor and batteries.

How to save energy running your central A/C

2011-07-25T01:37:00.010-06:00

Isn't central A/C wonderful? Its so cool and comfortable but on the other hand, so darn expensive.

My last house had an evaporative cooler on the roof. It's basically a system that draws hot, dry air through water soaked pads. The heat in the air is absorbed when the water evaporates. Hot, dry air goes in and cool, more humid air comes out. When the humidity is low, it works beautifully. When it's muggy outside, well, that's where the evaporative cooler gets it's “swamp” nickname. In a dry climate like Utah, the swamp cooler is extremely efficient, somewhere on the order of 48 SEER. A typical central A/C is only 10-18 SEER.

Psychometric chart

A properly tuned and maintained swamp cooler will produce air that is a couple degrees above the wet-bulb temperature. So if it's 110 °F outside with only 10% humidity, the wet-bulb temperature will be 68 °F and the air coming out of the swamp cooler will be about 71°F. Not a bad system for a really dry climate.

A few weeks ago, I was pondering the idea of combining a central A/C with a swamp cooler. They do it all the time in the chillers on large commercial air conditioning systems. Why don't A/C manufactures offer it in their products to homeowners?

After a few hours reading on the home HVAC installer forums, I learned that people who ask this question, “Why not wet down a central A/C?” are flogged and burned at the stake so to speak.

Evaporating lots of water on thin metal cooling fins is the quickest way to rust and corrode them. A modest savings of power up front will end up costing the homeowner a new A/C unit in a few years.

Being an exceedingly curious man, I just can't put the issue to bed that easily. Yes, I can see how wetting down cooling fins with hard water is just asking for trouble, not to mention increased maintenance and the potential for flooding problems. But I believe that under the stretched out tent walls of a generalized bad idea lie stringent ruled, brilliant ideas.

To protect the uneducated public from injury and damage, an idea that is dangerous some of the time is stereotyped as a bad idea all the time.

For example, “Never put metal in the microwave”. Now this might seem like good advice to follow because we have all been raised to believe it is true in all cases; that it is dangerous to put metal in the microwave.

But you forget that microwave ovens are made of metal. Some microwave ovens even come with metal shelves and metal temperature probes. “No metal in the microwave oven” is a contradiction. The more correct statement should be, “Never put metal in the microwave oven when the dielectric properties and electrical dimensions of the metal and food pieces will cause excessive heating and current flow across the metal.” To simplify our lives by not having to crunch a bunch of energy density functions and calculations each time you need to re-heat something, it is generally easier just to not put any metal in the microwave oven.

There will always be exceptions to rules and contradictory exceptions to those exceptions.

FYI#1:You can defrost an open can of juice concentrate in the microwave oven, even though the bottom of the can is made of metal.

FYI#2: Re-heating in a microwave oven an Arby's roast beef sandwich shrouded in its metal lined paper wrapping will cause it to catch fire. Right Marv?

Just as with exceptions to the "no metal in the microwave" rule, I believe that under the right circumstances, cooling the A/C coils with water (softened water) is a good idea and will save energy without significantly shortening the life of the A/C system itself. If I am wrong, I get to buy a more energy efficient A/C coil to replace the one I currently have.

It is my goal to confirm the following statements:

Removing direct sunlight by shading the outside A/C coil (without limiting airflow) will lower the power consumption of the compressor during those hours of direct sun-light.
Lowering the temperature of the air conditioner coils (outside unit) will lower coolant pressure, lower compressor current draw and make the A/C run more efficiently.
Adding powered attic ventilation in a properly air sealed home will make the central air conditioner run less and reduce overall power consumption.

I know that doing the above steps could potentially save energy. How much? Well, that's where experimenting comes in.

My house is already pretty well insulated. I also air sealed major air penetration areas of the home, (recessed lights, plug sockets, windows) and added more passive attic ventilation. These low lying, energy saving fruits are already harvested.

Central Air Conditioner Coil Shade:

Using my TED house power monitoring system, I noticed that between the hours of 5-8PM, the duty cycle of the air conditioner goes way up. I also noticed that it was during those same hours that the setting sun is beating down on the air conditioner unit outside.

I decided to build a shade to see if that would improve anything.

To my surprise, with the tarp shade, the power consumption of the air conditioner while it was running did not change much but the duty cycle of the air conditioner's "on" cycle, shortened.

That worked so well that I spent $100 on a couple sheets of grey PVC lattis and channel pieces. I built a more permanent trellis shade that looks nice and still shortens the A/C duty cycle during the evening sun hours.

This shade results in a 1.9KWH/day air conditioner energy savings with the added benefit of looking less like a crime scene than the tarp.

Central Air Conditioner Misting System:
To cool the outside air temperature, I originally thought of building a swamp cooler around the central A/C unit outside. That cost estimate quickly rocketed up into the $400 range. I'm all for advancing science and mankind's well-being but I don't want to blow that much money this early in the game.

I ended up going with a simple misting design (with 15-20 misting heads) that would allow for more airflow to the A/C coils. There are products on the web that do just that for about $100, but they are for smaller A/C units and adding enough misters for my size A/C unit add up to over $200. Plus I didn't like the toilet flapper float design they used for turning on and off the water supply line.

For about $45 I built my own misting system that uses an electronic sprinkler valve controlled by the existing HVAC thermostat.

The water feeds through from an unused hose bib near by into the sprinkler valve.

How cool and and refreshing is that?

The misting system reduces the outside air temperature, in turn reducing the pressure of the whole system, in turn reducing the air conditioner's power consumption 850 watts (or 21%) while it is running its cooling cycle. This results in a 4.8KWH/day air conditioner energy savings.

I still need to run a soft water line out to the misting system, before the A/C coil is sentenced to a corroded, rusty fate.

Attic Fans:

A couple of years ago, I installed a thermostat controlled attic fan. I had read that venting out the heat in the attic will reduce cooling costs, (makes sense). But it also takes energy to spin a large fan for 10 hours every day.

If the house isn't properly air sealed, cool conditioned air from the house will be sucked into the attic space and vented outside. In this case, the central air conditioner will use more energy with an attic fan running.

If the attic is far under ventilated, the attic fan will not be able to draw out enough hot air to make a difference but still draw a lot of power.

If the attic has superior ventilation (most homes, including mine don't), an attic fan will not do any good either because the attic vents are already doing the an attic fan's job only passively.

Ever since I air-sealed my home, I have been wanting to quantify the attic fan's performance and usefulness. I got the chance this weekend when my entire family was away and left me home alone. No stoves cooking, no kids leaving outside doors open, no TV's being left on. Just a relatively constant, measurable whole house power consumption. To help in comparing apples to apples, the weather forecast all weekend was sunny and in the low 90's .

I ran one day with the attic fan on and one day with it off.

Notice how the air conditioner has shorter duty cycles on the day the attic fan is running.

All things being equal and even with R-38 insulation in the attic, the attic fan lowered the central air conditioner's power consumption by 20%.
Even though my attic fan draws 190 watts when it is running (190x10hrs/day = 1.9KWH), it actually reduced the central A/C usage by 6.6KWH for a net gain of 4.7KWH.
After operating for 2 summer seasons and at an electrical savings of $70/ season, my attic fan just paid for itself last year.

Between the A/C trellis shade (1.9KWH savings), the A/C misting system (4.8KWH savings) and the attic fan (4.7KWH savings), my whole house net energy savings is 11.4KWH/day or a 22% reduction. COOL!

Shoot, with the energy saved by not using an extra 11.4KWH/day all summer long, I could drive an electric vehicle 3420 miles, or commute in it to work for 5 months, FOR FREE!

Update 7/27/2011:
I have since plumbed my hose bib to the soft water line. Now the misting system will not corrode the coil nearly as fast; maybe not at all.

Water Conservation:

2011-06-23T22:40:00.008-06:00

I live in the desert landscape of the Wasatch front in northern Utah. I say desert because that is what it used to be when the Mormon pioneers settled here almost 164 years ago. When they arrived, the Prophet and leader Brigham Young proclaimed, “This is the place!” I wonder if this was actually a question and not a statement? Perhaps he really meant, “This is the place?”
Either way, those early Mormon pioneers took a dry piece of desert land and transform it into a fruitful, lush, green oasis. Today over 2 million people live here and it is a beautiful, green, mountainous landscape.
We all have to start being more conservative if we expect to sustain our American lifestyle on such a finite water resource. It is possible for all of us and our children to have luxuries and amenities. We just have to be smart with how we use our resources.

Use low-flow shower heads:
This is good practice but you can even take it a step further. Hop in the shower, get wet, rinse off, then turn off water. At this point, take your time lathering up and scrubbing yourself clean. When done, turn the water back on and rinse off. You will only use 3-8 gallons for your shower. Without the water washing the soap away before it has had a chance to do its job, you will get cleaner and use less soap in the process.

Drain Water Heat Recovery:
It takes a lot of energy to heat water. It's a shame that all that energy ends up going down the drain.
By using a Heat-recovery drain pipe, one can recover 80-90% of that wasted energy. When water runs down a vertical pipe, rather than falling down the center very quickly, it glides down the inside wall of the pipe. In a heat recovery drain, a section of vertical sewer pipe is replaced with a thermally conductive copper one, a smaller copper culinary water pipe is wrapped around the copper sewer pipe. In this manner, heat from warm waste water (and nothing else) is transferred to the cold water on its way to the water heater. A typical system costs about $500-$800 and the pay off ranges from 2-7 years depending on how much you use it. Heat from shower water is easily reclaimed because there is a continual flow of warm waste water preheating the continual flow of cold water entering the water heater. I want to install one of these someday.

Use an efficient washing machine:
Spend a little extra up front and save a bunch throughout the life of the appliance. Energy Efficient washing machines will save you thousands of gallons of water each year and reduce the energy consumed drying clothes because they spin clothes faster making them drier.
I recently replaced my old washing machine and electric clothes drier with an energy efficient, front loading washing machine and a gas drier. My electric bill went down 120KWH/month by drying 8 loads/week with gas instead of electricity. But to my surprise, my gas bill also went down. Even though my clothes drier now runs on natural gas, the washing machine uses so little water now (2.2 gallons/load) that the water heater doesn't have to heat up nearly as much water to feed the washing machine. The result is a net reduction in electricity and natural gas consumption.

Fix drippy faucets and running toilets:
A drippy faucet can annoy the crap out of you and also wastes 20-100 gallons of water in a day. Leaky hot water wastes energy too because your water heater has to heat up all that water before it gets lost.

Saving Water Around the Yard:
I am not very stringent in this area. I own a large ½ acre lot, that is mostly lawn. Kentucky Bluegrass is not native to arid Utah. It takes a lot of water to keep it green and happy. But that is what the cavalier American dream demands, right? A lush, manicured, green lawn? You have to admit though, it does look pretty good.

It also feels good walking barefoot or laying down on a healthy green lawn. The kids love to play on it too. Even for an energy sipping tree-hugger like myself, I justified putting it in. My wife may have twisted my arm a little bit.
I read on the Internet that an acre of grass sequesters 3 tons of CO2 each year.  There is a lot of research ongoing regarding this topic. The sequestration numbers vary from several tons of CO2 per acre per year to lawns actually being a net carbon source.

Even with my property having a large irrigation water share, I still hate to see any of it going to waste.
If you have a choice, buy a house that has secondary water for watering the yard. Living in Utah, I am baffled why most homes here only have a culinary water supply. It's expensive to water a large lawn with culinary water, not to mention a terrible waste of a limited resource.

Regardless of the water source, water the lawn in the early morning to limit evaporation. Make sure sprinkler heads are in good repair and automatic sprinkler valves turn on and off correctly. In my last house, I only had culinary water. I had a sprinkler zone dedicated to watering several strawberry plants. One day, the valve got stuck in the on position. I didn't notice it until after returning from a vacation. Needless to say, the strawberries were amazing, but not as amazing as my water bill.

Only water the lawn from a couple times a week to every other day. When you do water, give the lawn a good soaking, then allow the ground to dry out for a few days. This promotes a healthier lawn by sending the roots deep in search of water. Deep roots enable the plant to go longer between watering intervals.

Collect rain water for use later in the year:
Why pay for water when mother nature already gives you the water for free? Acquire a large cistern that can collect snow melt and rain water from the roof. During the summer months when it is dry, this water can be conservatively issued to the plants in the yard.

Xeriscape yard:
Only plant native plants in the yard that thrive solely off of the natural water cycle. No irrigation is required.
Check out your local water conservation district. They have examples and ideas of yard landscapes that will work in your local geography.

Drink Water:
Anyone else thirsty? Don't buy a Coke! Drink water!! Fill up a bottle from home and drink up. It's free!
Milk is for Graham Crackers. Juice is for special occasions. Water is great anytime.

Solar Panels 6 Months Later

2011-06-03T23:37:00.011-06:00

It has been over 6 months since I installed solar panels and started making my own electricity.

To recap, December was not a good month for solar energy. My panels only made 160kwh all month and I used 310kwh more than I made. Just by looking at daily solar panel production for December, you can extrapolate when the winter solstice took place (TED started collecting data on December 4th).

Even though solar panels are more efficient at making power when they are cold, having less hours of the day really hurts production.

January more than doubled December's production with 380kwh. February almost doubled it again and nearly zeroed out the net meter. March was the first month where production equaled consumption. Even with all the record rain fall and cloudy weather in Northern Utah, the months of April and May produced enough power to run my house for 3 months. I can't wait to see production on months where it doesn't rain every day. This unseasonably cold weather and cloudy skies hampered available solar energy but at the same time, I hardly had to turn on the air conditioner.

I am currently producing twice the energy of what I consume. On a sunny day, I make over 3X.
My utility company allows me to build up a one-for-one credit with them so long as I use up that credit within 12 months of accruing it. Under this system, the grid is effectively my battery. A non-volatile, unlimited capacity, low cost, maintenance free battery. All I pay is the $5/month fee, well worth the price in my opinion. The electric company lets me do this because I am helping them reduce their peak demand. Solar panels are the perfect solution to preventing rolling blackouts.

As of today, I have built up nearly 2 months worth of energy credit.

In hindsight, a 6.2Kilowatt solar system is a little too large for powering just my house. But when I first looked into getting solar panels, my energy consumption was much higher than it is now. An un-calculated side effect of having solar power (and a TED whole house monitoring system) is a lifestyle change. Having a device that points out to you that you are being extremely wasteful will change the way you act and think forever.

This increased awareness has indirectly reduced my energy consumption by 1/3^rd. All the while, my standard of living has remained the same or even increased.

Now that I am making more energy than I will use in a year, I need to put it to good use before I have to give it away for free, which isn't exactly the end of the world either -- actually I would be saving the world then wouldn't I. Here are a few ideas.

Make some hydrogen

Using electricity, one can split water molecules into oxygen and hydrogen. Storing hydrogen is tricky because it takes a lot of space and doesn't have a very high energy density. But once you have it stored in tanks, you could then use it to power a fuel cell and generate electricity during a power outage. Or you could burn it directly for cooking or heating.

Heat the home in the winter months

A deca-therm of natural gas is equivalent to 293KWH. Heating my home for the winter (using an electric furnace instead of natural gas) would require 16,500KWH. I would need a solar system nearly twice as large as what I have now just to run the furnace for the winter. This would be a stupidly inefficient way to heat a house. Still, if I have energy to burn, why not? Nah.

Charge an electric car

Charging an electric Chevy S-10 pickup truck after driving it 40 miles will require somewhere in the neighborhood of 9KWH of electricity. I drive my current commuter car about 8000 miles a year. That works out to only needing 1800KWH/year. That would be perfectly doable with my estimated surplus and save me about $820 in gas each year. This would also knock the return on investment for the solar system down from 6 years to just over 3 years. Hmmmm.

Power a Time Machine
Too cliche. By the way, a few years from now, I actually invented a time machine and went back in time to a few hours from now. Apparently, it didn't go very well and an even older version of myself had to go back in time to a few minutes ago and stop the whole event from taking place. Time travel is tricky like that, not to mention it takes a ton of power and the stupid machine kept blowing the main breaker.
Time travel, Shmime travel, I just want a microwave oven clock that doesn't have to be reset each time the power goes out.

Nissan Leaf vs. Chevy S10 pickup

2011-05-28T14:51:00.004-06:00

A few years ago, my sister was getting rid of her Geo Metro so I bought it off of her for $1.

I had great plans to convert it to an all electric car. I only needed a 30 mile max range for my commute to work and back. The Geo was the ideal car for converting to EV. It was light weight and had good handling. People have used them for years as a donor car for electric cars.

I stripped out the engine and acquired most the parts I needed, One day, we decided to move to a larger house. Sadly I had to admit defeat when the house we moved in to was out of the range of the electric car's design. I chocked it up to a learning experience and sold the parts, liquefying my asset.

To this day, I still consider this poor excuse for an excuse my greatest failure. I vow that my next vehicle will be an all electric car.

I have been thinking about two options: The Nissan Leaf or converting a Chevy S10 pickup truck to an electric vehicle.

Let's list the pros and cons:

The Nissan Leaf is very expensive but super cool. The Chevy S10 EV will be about 1/3^rd the cost and also super cool.
The Nissan Leaf is a new car filled with the latest technological gadgets.
The Chevy S10 pickup EV will be very basic and plain. I've never had such fancy stuff in a car so why start now?
The Leaf has a 100 mile range. The S10 EV will be lucky to get 60 miles. My commute is only 20 miles each way.
The S10 being a pickup truck will be able to haul lumber, sheet-rock, dirt and bags of concrete mix.
My current vehicle (1992 Honda Accord) has been my reliable “work truck” and has served me well in hauling everything except for Sheetrock. The Leaf would be too expensive to use in this manner.
The S10 would be a total blast to strip down and convert over to an electric car. I need me a new hobby! The Leaf, well.... Not much to do on it. Drive it home and then what?
The Leaf will cost me almost $31,000 where as the S10 will set me back $11,600. I could buy a lot of whatever with the $18,900 saved in rolling my own instead of buying a bran new car.

Nissan Leaf (100 miles) Chevy S-10 (60 mile range)
Car $33,720.00 Minor repair work $250.00

Charging station $2,200.00 Donor vehicle '94-98 S10 $1,750.00

Rebate -$7,500.00 A/C Electric Kit $8,115.00

Acquisition Fee $595.00 x18 T-145 6V batteries $3,222.00

Taxes $1,958.51 Miscellaneous $500.00

Sell Honda -$500.00 Sell Honda -$500.00

Tax Credit -$1,333.70

Sell old truck parts -$400.00

Net Cost Leaf $30,473.51 Net Cost Chevy S10 EV $11,603.30

Savings of converting vs. buying new $18,870.21

Which begs the question, why not drop an extra $4000 on Lithium batteries instead of lead acid ones.
Pound for pound, lithium batteries have 3 times the capacity of lead acid. Not only would the S10 have extended range but it would also have increased weight carrying capacity. Since the batteries are the last thing I would buy when converting to an electric car, I have time to give this more thought.

The Results Are In!
I'm going to try my hand at converting another electric car. Now I just need to find a cheap S10 with a zillion miles but a good frame, body and interior.

Lawn Mowers

2011-05-20T14:26:00.076-06:00

I prefer electric lawn mowers to gas ones because they are super quiet, they don't pollute and I don't have to buy gas.   The only problem is corded electric models are a hassle and cordless mowers, due to limited battery capacity are only suited for small lawns. For my ½ acre lot, neither option was acceptable.

John's Rule #106: If you can't find what you need, invent it!

My lawn mower uses a 115 Amp-Hour, 12V deep cycle battery to power a 750 watt AC inverter that in turn powers a 157 VDC motor that has been connected to a bridge rectifier so it can run off of normal household AC power. Granted, it’s kind of stupid to convert DC to AC and back again to DC but that’s exactly when I have done.  The down side to my Frankenstein mower is that it's not self propelled and the deep cycle battery on board weighs a lot.
I'm still looking for the parts so I can connect a 12 volt motor to the back wheels.  In the mean time, mowing the lawn is good exercise.
When my mower is drawing the maximum amount of power, the 12 volt battery has to provide 62.5Amps continuously. That gives me 1 hour 50 minutes before the battery goes totally dead. This isn't a problem because my lawn only takes about an hour to mow and the mower doesn't always draw maximum power anyway.

750 watts is only 1 horsepower but an electric motor is way more efficient than a gas engine. My lawn mower has the equivalent grass cutting abilities of a 3.5HP gas mower.

This season, I have been baffled as to why it has been taking me 2 deep cycle batteries to mow my large lawn instead of only one. Last season, I would boast that I could mow the entire lawn and only use ½ the capacity of my battery.
Having my lawn recently aerated left thousands of little grass poops all over the lawn. You should have seen my 2-year-old daughter, (thinking they were dog poops), try to walk across the lawn with ever-so-much care and caution. She had such a cute, disgusted and worried look on her face.

Mowing the lawn after aeration, the occasional lawn poop would hit the blade with a “twang” before being obliterated. It was fun to do but it wrecked havoc on the blade.

I sharpened my spoon sharp lawnmower blade to that of a spinning-death steak-knife. The revived blade helped a moderate amount but my mower would still bog down in long, thick grass. What is going on here?
Then it occurred to me that the first time I mowed the lawn this season, I lowered the blade down to a 2" cutting height and I neglected to raise it back up to the original height of 2 ¾”. After raising the blade back up, I was able to mow the entire lawn using only one battery.

After measuring my lawn mower's performance (with a Kill-A-Watt meter) and applying some crude calculations, I arrived at these surprising statistics:

A sharp lawnmower blade will use 33% less energy than a dull blade.
Raising up the deck only ¾", extends the range of the lawn mower by 40%.

This is true for gas or electric lawn mowers.

Unless you have a putting green, there is no practical reason to cut the lawn short. I found that cutting the grass a little bit longer will in return yield several benefits:

A healthier lawn.

The lawn remains greener with less water.

Takes less time to cut.

The lawn mower does a better job of cutting/mulching the grass.

And amazingly, it uses less energy.

After collecting data from a few of my neighbors about their lawn mowers, I found that a ½ acre lot can be mowed using 1 tank of gas (0.4 gallons) at a fuel cost of $1.50/week, spanning a 21 week grass mowing season. Using these figures, my $84 battery needs to last at least 2.4 years to pay for itself.
Well, it has already done that since I am into my 3rd year of using this battery.

After mowing, the battery is only 45% discharged. Conveniently, this also extends the overall life of the battery.

The x-axis is the discharge percentage of the battery. The y-axis is the number of charge cycles.

Amazingly, only discharging 45% will allow a battery to last 1200 charge cycles, (1200/21 = 57 years). Due to the cheapness of my battery, I'm conservatively estimating mine will only last for 250 charge cycles or 12 years. We'll see.

My ½ acre lot with ~¼ acre of lawn requires ~0.7KWH of energy from the battery and 1KWH of electricity to recharge the battery. That’s about 10 cents per week to mow my lawn. Since solar panels provide all my electricity, my lawn mower is effectively solar powered.

Nerdy Fun Facts:

There are 125,000 BTU in a gallon of gasoline and 3412 BTU in a KWH. An equivalent gallon of electricity would be 36.6KWH.
Gasoline has an amazingly high energy density. Storing the same amount of electrical energy (as a gallon of gas) into cheap deep cycle lead acid batteries would require 2036 lbs of batteries. Since you can never retrieve 100% of the energy stored in a battery, you would actually need more than this.
A typical push mower has a 0.4 gallon gas tank. My electric lawn mower uses 15 times less energy to mow a lawn than a gas mower.
The deep cycle battery on my lawn mower weighs 78 lbs but only releases the (usable) equivalent energy contained in 2¼ ounces of gas.
The ideal grass cutting height (in my opinion) is: 2 ¾“. This saves the most energy but still keeps the grass relatively short and manicured.
You can measure your own lawn mower's cutting height by placing the lawn mower on flat cement. Measure from the ground to the bottom of the lawn mower deck. The cutting height will be 0" -¼" higher than this.

Update:
The weak link in the run-time for my lawn mower is the inverter's low voltage cutoff circuit. Once the voltage at the inverter drops below 10.7 volts, it's game over. After drawing 60 amps from a 12 volt battery for 50 minutes continuously, the battery voltage (while drawing a heavy load) is about 10.9 volts. The voltage drop across the 18" cables running from the battery to the inverter is about 0.2 volts with a resistance of 0.004 ohms. After beefing up the cables with much larger gauge wire, the voltage drop is only 0.03volts and only 0.0007 ohms.

The small red and black cables were what was used before. I added the larger red and blue cables.

I can always tell when my lawn mower battery is around 55% because (while pulling 60 amps), that is when my inverter starts squawking about low voltage. Before beefing up the cables, I was never able to discharge the batteries below 50% before the inverter's low voltage circuit pulled the plug on my mowing "fun". After I reduced the voltage drop across my cables, I can complete the entire lawn without the inverter voicing a single complaint. This effectively bought me an extra 25 minutes of run-time.

I am toying with the idea of swapping out my 78 lb lead acid battery for a 28 lb, 100AHR LiFe battery. But at over $500, can I justify the cost? Dang! Science can be expensive.

Increase Your Gas Mileage by 41%, No! Wait!! By Over 63%

2011-05-13T16:35:00.004-06:00

Last month I wrote an article about how you can increase your gas mileage 41%. I'm here to report that this figure was grossly inaccurate. The truth is, you can actually increase your gas mileage by over 63%. I know this because I have done it, reliably. As I learn more techniques and tips, my gas mileage just keeps getting better and better. Achieving such dramatic efficiencies in a normal internal combustion engine does not require doing anything drastic, dangerous or illegal. There are some people that use more"shady" techniques like drafting off of semi trucks. While this may increase their fuel economy, it is illegal, dangerous and doesn't reduce the environmental impact of burning fossil fuels. It merely passes the costs of fuel from the drafter to the truck driver.
I was able to increase my performance an additional 22% (above the 41% I was already achieving) for a total of a 63% increase. This latest 22% requires installing a tool that provides instant feedback about how driving style is effecting the fuel economy and changing your driving style to attain maximum fuel economy. Instant feedback is the key to such dramatic fuel savings.
One such tool is the vacuum gauge. It will work on any vehicle, costs you less than $30 yet it will save you hundreds at the pump.

The Vacuum Gauge that I installed in my 1992 Honda Accord displays a vacuum pressure ranging from 0 to 30 Hg (inches of Mercury).

The gauge's vacuum hose connects to the extra port on my intake manifold. How convenient that there was an extra port. No cutting or splicing involved.

Vacuum pressure at the intake manifold is loosely correlated to fuel efficiency. The harder you push on the gas pedal, the lower the vacuum pressure and the more gas your vehicle will consume. For my car, the gauge displays 0Hg at full throttle and as high as 24Hg when it is coasting in gear. My car gets much, much higher gas mileage when I drive in a manner that keeps the vacuum pressure as high as possible. Typically this is in the 12-18Hg range.
Cruising on the freeway I can maintain a vacuum pressure of 15Hg. The vacuum gauge also doubles as an inclinometer. Driving up a hill (like an overpass) while maintaining a constant speed, the vacuum gauge will drop down toward 10Hg. Driving down the other side, the gauge jumps up toward 20Hg.
By driving so that the vacuum gauge remains at a constant vacuum pressure, your speed may fluctuate, your acceleration will be smaller but your fuel efficiency will be much, much higher.

From last week's blog post, we learned that when a vehicle is driven at a low engine RPM, fuel economy goes way up. But pushing too hard on the gas pedal while in an upper gear will bog the engine down, potentially negating any fuel savings (automatic transmissions don't suffer from this but they don't get as good of fuel economy either).
Fortunately, the vacuum gauge will indicate if you are bogging the engine or not. If you are cruising along a 30mph street in 4th or 5th gear, with very little throttle, the vacuum gauge will still display a nominal value. But even an unnoticeable increase in throttle position will bog the engine down and kill the vacuum pressure at the intake manifold, increasing fuel consumption. Having this feedback is key to driving at the lowest possible RPM while still preventing bogging and preserving fuel efficiency.

For vehicles newer than 1996, the superior version of the vacuum gauge is the Scan Gauge II.
Not only does the Scan Gauge calculate and display dozens of parameters like miles per gallon, gallons per hour, total trip cost, closed loop status and engine temperatures, it can also be programed with vehicle specific gauges for your particular vehicle. For example, for my wife's Chevy Venture, it will display horse power, engine torque, air/fuel ratio, transmission temperature and even an obscure parameter called “knock retard”, (how many degrees of ignition time advance must be removed to compensate for low octane fuel, thus preventing engine knocking). For hybrid vehicles, the Scan Gauge will display "state of charge" and the regenerative charge rate of the battery system.

Efficient driving habits will save you money at the pump in exchange for a slight increase in commute time.

For me, slower acceleration and reduced cruising speed adds 3 additional minutes to my 20 mile commute. In exchange, I only have to pay to fill up for gas tank every 4 weeks instead of every two and a half. Not a bad compromise in my opinion.