Gearbox Magazine exists to do three things and we’ve got a short post about it on GBXM.net.

Last time I talked a lot about batteries and range, this was a logical starting point as the choice of batteries due to my budget dictated heavy weight lead acid batteries, and the desired range (around 35-40 miles) pointed towards a larger pack, and therefor a truck.

I’d now like to look at controllers. There are a lot of factors that determine controller choice, but for me, and I’m sure for many of you, cost is going to be the deciding factor. First is system voltage. Controllers range from 24 volt all the way up to 300+ volt for some applications. My pack voltage will be 120v, and to move a truck from a dead stop with a normal pace , I think I need something that will pull 500 amps safely.

500a x 120v is 60kw This amount of power is only used for a fraction of accelerating time. 1st or 2nd gear, within the 3-4 second range, after that, the amp draw will fall off to below 200-150a. (60 kw is roughly 81 hp)

So, what are my choices ?

Top of the line:

http://www.cafeelectric.com/ – The Cafe Electric Zilla – high voltage 1000 and 2000 amp configurations. As I’ve said before in previous interviews with conversionists, this is the most coveted controller for any EV enthusiast. There is a waiting list, and they start at about $2,500 so for me it’s a bit of a stretch. I aim for this conversion to come in under $10k

Soliton 1 DC motor Controller – If you’ve got the money it is highly recommended, especially since it comes already with build in water cooling. – Between $2,900 and $3,200

Warp Drive controller – In the 72-200v 1000amp config this controller costs $1,900, so realistically it is still in the running, costing only $400 more than the Curtis. Also comes pre-piped for water cooling.

Midrange:

http://www.evalbum.com/dcp – DC Power Systems Raptor 600/1200 – These controllers are more Top of the line than most out there, I’ve heard good and bad. Unfortunately they are no longer made. I have seen a reconditioned unit for sale for $800.

http://www.cloudelectric.com/product_p/co-1231c-8601.htm – Curtis 1231C-8601 96-144vdc 500amp – around $1,500 new, and perhaps 8-900 used.

I’m pretty sure this is where my solution lies. It’s not too expensive, I’ve seen lots of conversions with them and I don’t have to build it myself (not keen on that ;) If I could get my hands on a pre-built version of Paul Home’s open source controller I would probably consider that over this one.

Specifically as Joe Yanoff mentioned, the Curtis does want to go into voltage cutback given our Arizona temperatures. For this reason, I will be adding active cooling, either Peltier devices or water block cooling, in addition to high power fans.

The advantage of this controller is also that it tops out at 144vdc, allowing for greater pack voltages will help if I ever manage to make the jump to lithium. Or a small scale arc reactor. ;)

(More on Curtis products here – http://www.curtisinstruments.com/index.cfm?fuseaction=ProductsGrid.Series)

Economy:

http://www.cloudelectric.com/product_p/co-kdh12600b.htm – Kelly 24-120vdc 600 amp

If I can’t get a used Curtis, I will most likely end up with a brand new Kelly :)

By the way, for anyone looking for used EV parts like me here is an indispensable site – www.evtradinpost.com

Progress

Is slow. But its coming. I hope to have the engine removed by the end of January. The next step will be to replace the clutch and slave cylinder.

Junk in the trunk ... or bed.

Stuff slowly being removed / falling off.

The radiator was junk, the overflow tank was full of oily sludge. The Exhaust system was barely attached and quite easy to remove :) I lucked out, no problem nuts. The bed is loose, but it has still yet to sprout legs and leave my garage.

Here’s what I hope my battery pack will look like:

Thanks to EVHelp.com

Pictured are 16 batteries right behind the cab. I need 20, so I will add 4 in another row, or perhaps behind the rear axle, or in two smaller boxes either side of the drive shaft, under where some sort of bed will go. I don’t want any batteries (other than the accessory battery) under the hood. I’d like that area left as open as possible, so I can see the motor. The charger will most likely be under the hood also, more on that later ;)

Looking Forward

EV Gearbox will be continuing into the new year and nurturing a database of interviews. Hopefully along the way I can help provide some sort of technical insight into building an EV with the interviews and also progress reports on the truck.

It’s been a great experience so far and I have learned a lot, I will continue the trend :)

As always I would be delighted to hear from any EV owners who want their conversion featured on the site. I admit I am not that good at searching for story leads, so if a conversionist emails me first it really helps ;)

]]> http://ev.gearboxmagazine.com/2010/12/29/updates-and-looking-forward/feed/ 2 http://ev.gearboxmagazine.com/2010/11/04/joe-yanofs-1989-corolla-ev/ http://ev.gearboxmagazine.com/2010/11/04/joe-yanofs-1989-corolla-ev/#comments Thu, 04 Nov 2010 09:30:01 +0000 Dave Hymers http://ev.gearboxmagazine.com/?p=192 Joe Yanof’s  1989 Corolla EV

Name, Age, location ?

Joe Yanof, 29, Phoenix AZ

What is your primary occupation ?

I’m an engineer at Honeywell designing mechanical systems for jet engines that go in helicopters and business jets.

What got you interested in electric cars Joe ?

It started one of those summers when gas prices hit $3 a gallon (2007, i think).  My buddy and I thought there had to be a better way, so we started researching electric cars.  Preliminary research showed that going electric wouldn’t really be cost effective until gas was around 4-$5 a gallon, so we sidelined the idea.  Then, the next summer, gas prices did hit $4.50 a gallon, and that’s when I really got interested and the conversion started.

Of course, gas prices plummeted after that, but I’ve since realized other benefits of going electric (clean, quiet, simple, reliable fuel source, car pool lane, etc)

Is this your first EV ?

Yes, unless you count a couple RC cars I had when I was a kid.

Your EV has used two controllers, can you describe them ?

Actually, I’ve used 3.  They are all rated at 500A / 144V.

The first was a Kelly 500A 144v controller.  I was attracted to the lower price, but was misled by the ratings.  The controller pushed 500A for the first few seconds of a drive, but after that, it self-limited to about 350A.  My motor is a little undersized for the weight of the vehicle and it required a higher power controller.

I then upgraded to a Curtis controller.  This was that odd time in the hobby EV world where there were no controllers available.  Everything was either out of production or out of stock or having field problems.  I was able to find a Curtis 1231c at a dealer and swapped it for the Kelly.  Even though it has the same ratings, it was able to sustain the output required to accelerate reasonably (just need a few seconds of high current to get rolling).  However, once the weather warmed up, the Curtiswould trip into over-temp mode and cut back power more often.  Often, this happened at in-opportune situations, like making a left turn, or accelerating onto the highway.

I knew that the Curtis was an old design and that there must be something out there that’s better.  I had the good fortune of stumbling upon the open source controller project that Paul Holmes had started.  I liked the idea of a controller that is simple enough to build yourself that also performed really well.  He had just begun building his second prototype and was looking for volunteers to beta-test the controller.  With the hottest months of summer just ahead, I volunteered with the added benefit of testing the controller in one of the harshest environments.  We had some development issues, mostly tweaking software here and there, but it has since performed beautifully for 7000 miles and counting.  It runs a lot cooler than the curtis and thus performs better in the heat.  It’s completely silent, at all speeds.  It has many configurable options, such as battery amp limit, throttle response controls, motor over-speed sensing.  It’s also nice to be familiar with the design so that troubleshooting any problems that come up is easier.

(Paul’s website is here http://paulandsabrinasevstuff.com/)

Open source controller

24 lead acid batteries is a lot to fit into a coupe, how did you achieve this ?

The initial plan was to get as many under the hood as possible and then fit the rest in the trunk.  The only thing that really had a predefined location was the motor, so I planned to stuff batteries wherever I could and put the rest of the components in the space available.

I made a cardboard replica of the battery case to trial fit them and ended up finding room for 7 under the hood (4 in the radiator/condenser area and 3 above the motor).  This worked out well since the weight on the front wheels ended up about the same as before (no need to modify springs).  I initially planned to put 13 in the trunk, but once I got started, realized there was room for 4 more.

I think these older vehicles had a lot of room under the hood and in the trunk, and may have skimped on passenger compartment volume.  Nevertheless, there’s very little room for anything else besides batteries, and it’s really heavy!

Which battery did you use ?

USbattery – 2200′s, from a dealer in mesa AZ – they gave me a good deal since I was getting so many.

Did the battery boxes and fitting the batteries take lots of planning ?

The planning wasn’t too hard or time consuming.  Fabrication took forever!  Probably more than half the time converting the car was spent on fabricating the battery racks.  Of course, with batteries stuck in every nook and cranny, a lot of fabrication was required.

Did you aim to get as large a pack into as light a car as possible ?

This was my original intent.  They say that of the three characteristics (range, performance, low cost), a conversion can have two of them.  My long commute is 52 mi round trip and I didn’t have a ton of money to play with, so I chose range and cost.  Additionally, I knew that range would decrease in colder weather and get worse as the batteries aged.

So, I figured a small aerodynamic vehicle filled with batteries would best achieve my range goal throughout the life of the pack.  Of course, performance suffers, meaning acceleration and cornering are awful.

Living in Phoenix, you implemented an A/C system, where did you source the parts?

The a/c system was unfortunately an afterthought.  I didn’t intend to use a/c, but I must’ve been in la-la-land and somehow thought I could survive these summers.  There wasn’t any room for a separate motor / automotive compressor nor was there room to drive a compressor off the tail shaft.  I ended up using a compressor from the smallest window hvac unit i could find.  It’s from a 5k BTU zenith unit, i think.  The system uses the condenser that came with the unit, but I had to fabricate some of the copper tubing (from Ace) that connects it.  The long hose runs from the trunk to the firewall were made at a local a/c shop.  They also helped charge the system and test it out.

What’s nice about these scroll compressors is that they’re small and efficient.  However, they run on AC power, not DC, so I needed an inverter.  There are 12VDC to 120VAC inverters, but I thought it’d be silly to convert high voltage from the battery pack to low voltage and then back to high voltage.  So I did some research and built my own sinewave inverter that runs straight from the battery pack.

Unfortunately, 5k BTU isn’t quite enough for great a/c.  I get about 20-25F drop in temperature from the vents relative to the outside temp.  It’s fine when it’s 100F outside, but not so great when it’s 115!  I think 10k BTU would be better.

Lastly, since everything is electric (and not connected to the drive train), the a/c is easy to turn on and off by activating a few relays.  I found a radio controlled relay on ebay for $25 that has a 100m range.  It’s hooked up to activate all the required relays for the a/c and I now have a remote start for the air conditioning!

Does using the A/C affect range noticeably ?

The a/c uses about 3-4 battery amps at 150v, which is about 3-4% of the amount of power required to move the car down the highway at 55 mph.  This is hardly noticeable.  Another way to look at it:  If I left the a/c running for an hour, i’d use up about 1.5 miles’ worth of range.  But, of course this would be worse if I had a higher capacity a/c compressor.

How often do you water your batteries ?

About once a month or so, a little less in the winter.

Where did you buy your adaptor plate and coupler from ?

The adapter plate is made from a 16″ round piece of scrap aluminum.  A friend of mine has a 4-axis CNC milling machine.  I made some measurements and drew it up as a simple CAD sketch and he made it for the cost of the cutting bits.

The coupler was a challenge.  I had the female spline for the input shaft from the original clutch plate and a sprocket that I found on a surplus site that had the correct hub bore and keyway slot for the motor.  I just needed a way to connect the two.

I ended up grinding off the teeth of the sprocket so it was just a cylinder.  I found another piece of steel cylinder at the metal store that was the same diameter as the hub to act as a spacer between the hub and spline.  Another friend has a lathe and was able to cut the parts as required so they piloted well and fit together nicely.  He also welded them together and it came out very well balanced.

All in all, the adapter plate and coupler were inexpensive, but I was fortunate enough to be able to use some scrap metal and have some friends who are capable machinists.

What do you think the most critical part of the build was ?

For me, it mostly likely centered around getting the motor in place.  All of the component placement under the hood was based around the motor location, and the number of batteries in the trunk was based on how many I could get under the hood.  On top of that, proper alignment of the motor and transmission shafts is critical and potentially a lot of work to redo if something didn’t fit correctly.

Which EV enthusiast sites do you visit ?

I receive the EVDL and EVTech lists, and often visit DIYelectriccar and EcoModder.

Which are some of your favorite conversions or available new EVs ?

I’m intrigued by the Leaf – it seems very promising and I hope it’s a success.  The Volt is a good gateway eCar.  Maybe people purchase it and realize they only occasionally need the ICE engine.  Meanwhile, maybe battery technology improves or becomes cheaper, and more people realize that a pure EV (with perhaps a bit more range) would suit their lifestyle.

I haven’t seen other conversions, but I admire people who can find parts and put together a suitable vehicle for very little cash.  I’m also amazed at the technology and performance achieved at the other end of the spectrum.

What do your friends think of the car ?

They all think it’s pretty cool and ask about it a lot.  My engineer friends get a kick out of it, for sure.  I haven’t yet convinced anyone to convert their own vehicle, though.

What has your conversion experience taught you overall ?

A ton.  I didn’t know much about cars, welding, controllers, motors, batteries, etc… It seems each aspect of the conversion has it’s own little area of available expert knowledge – battery maintenance, crimping cables, best practice for wiring, and the list keeps going.  What’s fantastic is that much of this information is available on the web and there are a bunch of helpful people on the discussion forums.  Also, jumping on board with Paul Holmes and his DIY controller initiatedme into the world of electronics.  That’s been a lot of fun and I’ve got quite a few small electronics projects now.

What was your conversion cost including donor ?

donor – $300 on craigslist with a blown motor.

motor – $1700

controller – $400 or so

charger – $750

batteries – $2500

adapter plate – $250

coupler – $100

DCDC – $250

random other parts (new windshield, tires, steel for racks, wiring, gauges, etc) – $1500

So, maybe about $8k or so.  Quite a bit more if you included things I spent money on, tried them out, and realized it didn’t work well (like the Curtis Controller).

Do you have a favorite story about building or driving your EV ?

The EV grin is pretty special, especially after months of work.

Otherwise there’s the carpool lane story: In Arizona, a vehicle that is registered with electricity as a fuel source gets an emissions waiver and  a blue ‘alternative fuel’ license plate.  The main benefit of the blue license plate is that you’re allowed to drive in the carpool lane.  I don’t drive fast, but the carpool lane comes in handy when there’s traffic and the carpool lane is only going 45 mph anyway.  I save a lot of time and coulombs by avoiding the stop and go.

There’s this one stack in the freeway system where the 202 joins I-10 westbound.  I-10 comes around a 90degree bend and 202 has it’s own carpool lane offramp that joins the carpool lane of I-10… it’s the perfect place for a motorcycle cop to sit and catch carpool lane free-loaders who come around the bend or the dedicated offramp.  So I’m in the carpool lane and see him up ahead after the bend in the shade of an underpass.  His eyes follow my car as I, a lone passenger in a 22 year old vehicle driving in the carpool lane, approach his position.  I know exactly what he’s thinking.  I watch my mirrors as I pass by him and he whisks his bike around ready to chase me down.  But, he doesn’t get 5 ft before abruptly stopping with a frustrated look – must’ve seen the plates!

Are there a few people you’d like to thank ?

Definitely Yates and Larry for helping with the coupler and adapter plate.  Also, thanks to the guys at the Interstate Battery store in Mesa for helping with the pack and AZ Auto and Air in Tempe for all the help with the A/C system.

Is there anything else you’d like to mention ?

Once this battery pack starts to go, I do plan on upgrading to Lithium batteries.  I hope to get another year or so from this pack, so hopefully by then Lithium comes down in price a bit and there’s more data on the best BMS scheme for them.

Starting off with lead has been great for learning without risking a ton of money, but the car is very heavy, slow off the line, uses a lot of power going up hills, and just covers my daily commute needs.  A lithium pack of the same volume would reduce the weight of the vehicle by 25% and yet provide over 100 miles of range (at 55 mph) allowing for the random errand at lunch or trip to see my folks.

At that point, I wouldn’t need another car for my daily driving and could sell my Civic to cover some of the battery costs.  We’d take my wife’s car if heading up north for the weekend or some other long trip.  That’s the plan, at least.

While swapping battery packs, I’d also take the opportunity to re-do a few things in the car.  This was almost a kind of proof-of-concept vehicle to convince myself that going EV is possible and affordable for my needs, so there are some things I’d do differently.  For example, while the direct coupler is simplistic, I still have to shift quite a bit based on typical speed limits and gear ratios.  so, I plan on re-installing the clutch.

I think I’ll also try to be a little more strategic with the battery placement in an effort to have some trunk space.  I’ll look at putting batteries under the rear seat and where the spare tire compartment is.  This will take some serious modification to the vehicle, but since lithiums should require significantly less maintenance than flooded lead acids, I could potentially install, forget, and have trunk space.

Along the battery train of thought, I’ll also try to enclose the battery boxes so that there aren’t any exposed terminals.

Then, since the spare tire space may be filled with batteries, I’ll move the A/C unit and condenser back to the front of the car.  I’ll probably use the original vehicle’s condenser and look for a compressor that’s at least 10k BTU.  My inverter should be able to handle the extra load of a larger compressor.

Are there any EVs out there who you’d like to see on EV Gearbox ?

Unfortunately, I haven’t seen any other conversions.  You might be interested in talking to Paul Holmes though.  He has a budget-converted VW bug (I think) and is knee deep in a lot of open source EV hardware development.

More photos of Joes conversion can be found here http://picasaweb.google.com/jyanof/EcarAlbum?feat=directlink# and his EV Album page here http://www.evalbum.com/2358

Thanks again Joe :)

Al Swackhammer has taken his A.U. 1000 and built a very unique conversion with a lithium pack and AC drive.

Name, Age, Location ?

Al Swackhammer, 60, Edmonds, WA

What is your primary occupation ?

Maintenance Mechanic

What got you interested in electric cars Al ?

I wanted to do more for Mother Earth. This cars orginial engine was a three cylinder, two stroke. What a contrast now.

Is this your first EV ?

Oh Yes

Can you tell us a little about the Auto Union 1000s, it is a very unique car.

Auto Union AG was what is now known as Audi, back in the late fifties production of the Auto Union 1000 began. Auto Union first came together in 1932, composed of Audi, DKW, Horch, and Wander. Horch and Wander fell by the wayside after the war. DKW and Audi lasted. DKW made their last car in 1965 or so. Left Audi and NSU until 1977. Audi became sole owner of the Auto Union and in 1985 began to use the four rings logo for themselves.

Did you import it from Europe ?

I found this car on Craig’s List in Santa Barbara, CA

Was the car in good shape, did any restoration take place ?

The car came in pretty good shape. In the first three days it was completely taken apart. It has had a complete body off, nut and bolt restoration. This was my first and last paint and or restoration. Way too many hours.

Have you had trouble getting parts for it ?

I joined a DKW group. In the first months I got a Blue Cloud Magazine. In it was an article about Mr. Ferrall in Michigan. He had lots of parts for sale. He had to be out of his shop of many years in only a few weeks.

I could not afford or have need of all the parts. He wanted $20k for the lot. I asked him what would happen if no one bought them? He said “I don’t want to take them to the scale”. The metal recyclers. I offered to come to Michigan and retrieve the parts and sell them; Either on EBay or through the club. He would get 50% of what I got for them. He agreed and I flew to Michigan, rented a truck and brought the parts home. The sad thing for me, is that I have not needed many of the parts.

Have there been any unique challenges in converting a car of this age ?

The biggest challenge has been the folks I purchased the kit from. They were so much trouble I will not even mention their company name. One of the biggest challenges was voltage. I started out with 48 cells and it was just not enough power to take the hills here is the Seattle area. I have since added 12 more cells to make it a 200v system.

The transmission looks similar to a VW, are there parallels between the platforms ?

I don’t have much experience with even VW transmissions. So I am not sure. This car is a front wheel drive, four speed on the colum.

Who machined the adaptor plate ?

It was part of the kit and I never knew. I will say it is a pretty piece.

Where did you source your Li-Ion batteries ?

My first set came from China direct. What a story that is. My second set came from Lithium Storage. Very nice folks to deal with.

How heavy is the pack ?

The batteries weigh 6.84lbs each X 60 = 410+ lbs. Without battery box or BMS

What percentage of total GVW do you estimate that to be ?

I am over the orginial curb weight by just 250lbs  Curb weight was 1995lbs

You have an LCD screen in your dash for displaying info, what kind of data acquisition equipment did you implement ?

The screen is not being used at its full potential. It runs Windows CE 5. It also is running Electric Blue Motors computer.

Could you tell us a little bit about the Azure Dynamics AC motor and controller and their benefits ?

I chose Azure Dynamics’s for a few reasons. AC motors are usually lighter than DC motors. It is limited to 200 amps max. And it has regenerative braking. This car has drum brakes and now I rarely have to use my car brakes. And as an aside, Beth is one of the most helpful people you will want to meet. Kind and fast in response.

Which EV enthusiast sites do you visit ?

I am so new at this that I visit any and all I find. I have been a sponge for information. I am usually on overload.

Which are some of your favorite conversions or available new EVs ?

I lust after the Tesla. Until I win the lottery or someone offers me one for my car, it will only be lust. I look forward to the new vehicles coming to market. The new Leaf and the Aptera and of course the Tesla S are some of them.

What do your friends think of the car ?

Most of my friends are impressed that I was able to complete this project. But most of all impressed that it works and is driven daily.

What has your conversion experience taught you overall ?

Tenancy and perseverance. I had to paint the car twice. The first time I started to color sand I went through to the primer. I did not understand what a “WET COAT” was. I almost sold the project at that point. I took a break and painted it again. It has a lot of paint on it now. Parts are really hard to find. Even with my find with Mr. Ferrall, I have had to source parts from all over the World. And still I have not found all I need.

What was your conversion cost including donor ?

There is a running joke. I have one price when my wife is around and another one if she is not. But really, I have more in this than I had budgeted. Like maybe 4 times more. It is around $42k at this point. I don’t like to tell people that (or my wife) because I don’t want to scare them off from doing a conversion. I did a high end conversion for several reasons. One , is,” if it is worth doing, it is worth overdoing”.

Do you have a favorite story about building or driving your EV ?

I guess the paint story. Having never painted a car before I was somewhat intimated. This was a turning point for the completion of this project.

Are there a few people you’d like to thank ?

I have done this project mostly by myself. I wanted to say when it was done that I had done it myself. My wife is the most of all those that helped me to complete this project. She never ever complained about the time or money I have spent to do this. I have my friend Bob Porter that gave me suggestions on my paint work. My friends Sheryl and Gordy who purchased my first paint bill, for some help I did for them.

Is there anything else you’d like to mention ?

I hope that many more people will either do a project or purchase an Electric Vehicle. It is all about not using fossil fuels. It is easy to do and feels great.

Are there any EVs out there who you’d like to see on EV Gearbox ?

Yes, I have a friend, Dave, that has a really nice Honda that would be great for a article. He is in the process of doing the conversion to Lithium. Should be a fun drive.

While we’re waiting for me to get my act together with a couple of other EV posts, I’ll be laying out descriptions of various components and why I’m choosing which (mostly because I’m cheap).

This first post deals with why I am choosing Lead Acid batteries (because I’m cheap).

Right before I drove it home

Bring on the money pit

I recently bought a used Toyota Truck. A 1986 4spd with 170k, it’s not in terrible condition. $950 got me a truck that needs some TLC, but otherwise it’s pretty solid.

I settled on a truck because it gives me more options for carrying lead acid batteries. A lot of garage conversions use lead acid batteries. They’re cheap compared to lithium, and pretty easy to come by considering industrial uses, solar battery back ups, and of course golf carts.

Lead acid batteries will probably tolerate more abuse than a lithium pack. Lead acids don’t typically require a battery management system, Lithiums most certainly do. (Not only is the chemistry expensive, so is its management system.)

It is recommended, though, that some sort of battery balancing system is implemented (more on that later), usually consisting of a bypass circuit, so certain cells in the pack can be bypassed after they’re charged and others can be “balanced” up to a nominal cell voltage, before the charger thinks the pack is charged and ceases.  It certainly will lengthen the life of the pack.

Weight ratings, vehicle and axle.

So why a truck instead of a car? Put simply, you can get more range using a truck, because it can safely carry the batteries needed to do so.
My truck has a GVWR of 4,400 lbs, 2500 of which is the truck itself (?) That leaves me with about 1,500lbs for a payload, in this case, lead. The calculations I’ve been doing estimate the battery pack needed for my range will weigh around 1,200lbs leaving about 300lbs for payload not to exceed the 4,400 lb GVWR. (The GAWR, gross axle weight rating for the rear is 2,540 and front is 2,050.  I’m still confused as to what the weight of the truck is, but hey, I’m pretty sure it’ll handle 1,200lbs payload)

You can read a bunch more about lead acid batteries here and who makes the best ones:

http://www.electric-cars-are-for-girls.com/6-volt-golf-cart-battery.html

http://www.electric-cars-are-for-girls.com/8-volt-golf-cart-battery.html

Notice what is at the top of the 6v battery list? It’s the Trojan T-105 battery, ubiquitous in golf carts everywhere.

A 63lb hunk of lead and water. Onward to the future!

Also, I might be using abbreviations here so I’ll define them all here:  ah=Amp Hour, battery capacity is rated in ah. V= volts, yeah probably didn’t need that one. Wh = Watt hour and Kwh = Kilowatthour.

Why use 6 volt batteries ?

Well, to understand completely why, you’d probably have to solicit the opinion of a battery tech or someone who has built a couple of EVs.

A really good explanation is here: 2 setups, one with 8v and one with 6v: http://evdl.org/archive/#nabble-td2967658%7Ca2967686

(An 8v/12v pack might be easier to kill, basically, if you don’t limit your controller or driving habits accordingly.)

To move a vehicle with electricity takes differing amounts of voltage and current depending on a lot of factors, but the main one is weight. To move a larger vehicle, it’s a general rule that you will need higher voltage in a DC system, because, although you can get controllers that will pump 2000 amps, the usual range is 400-750amps and that is only for a few seconds usually.

So if Volts x Amps = Wattage (power) then higher voltage will keep our amperage down to a level we can buy a controller for (and that won’t exceed the battery discharge rate, which is usually 3C, Capacity x 3, in a simplistic example this would be 660 amps for the T-105).
For a car the size of a VW Bug, most lead acid conversions will be around 72-96v but that doesn’t mean you can’t go higher, again the only limitations are weight and space.

For something like a 1986 Toyota Truck or Chevy S-10, it is highly recommended that you don’t use less than 120v and most lead conversions go as high as 132 or 144v, some even as high as 180v.

Now what about range ?

How I have been calculating range is estimating the trucks efficiency, which is a stab in the dark, but I know a lot of converted trucks are between 350-450 watt hours per mile (reading amps x volts while driving, not while charging which will produce a figure taking into account power consumption before the battery pack).

Now, a Trojan T-105 battery is 6v and 220 amp hours for a watt-hour rating of 6×220 = 1320wh (This is the battery’s 20 hour rate, meaning if we put a load in it that discharged it at 11 amps, it would last about 20 hours before going dead. (11a x 6v x 20 hours = 1320wh))

KNOW THIS, when we are dabbling with the science of battery chemistries, there are certain physical properties which must be considered;

1. With lead acid batteries, the slower you discharge them, the more capacity you will be able to exploit. This is Peukert’s Law.

2.Fully discharging a battery will shorten its life. You have to assume your range is dependent on *not* fully depleting your battery.

Hence, this 220 amp hour figure is a little misleading, in our application, we will never see a battery’s full potential, for the above 2 reasons.
This is why we consider a batteries DOD or depth of discharge, opposite to its SOC, stage of charge (a battery with 80% DOD has 20% SOC).

For an EV with a fairly expensive set of batteries, you’ll want to build in the fact that you really don’t want to pass 75% DOD.

My pack will look like this: 20 x 6v = 120vdc. 20 batteries in series gives me 120volts, 220ah capacity. So 120v x 220ah = 26.4 kilowatt hours
Now, that 26.4kwh is a completely false number when we think about the 2 rules above.

So, I’m going to fudge a bit of math here to attempt to end up on the safe side of a battery estimate. I assume I’m never going to see more than 180ah of capacity from my pack because of Peukert’s Law in my application.

Then I will take into account that I want to only discharge my pack 75%.

120v x 180ah = 21.6kwh x .75 = 16,200wh

That is a full 10.2kwh lower. Thanks physics.

Ideally you’d want to be closer to a 50% DOD and depending on the real world requirements, efficiency and how fast I drive I might get close to that.

Ok, now we can estimate range.

Assuming a 450wh / mile EV efficiency; 16.2kwh / 450 = 40.5 miles

I actually need 28 miles one way. So far so good. (charge at home, then charge at work for the journey back)

Next post will be about Controllers or Motors/Adaptor plates. Stay tuned.

Netgain Impulse 9, meet B.O.B.

Occupation & Age ?

Business Owner, 52

Location ?

Shasta Lake, California

What got you interested in EVs Richard ?

Being a business owner, I’ve always been focused on efficiency, and electric vehicles are so much more efficient than internal combustion vehicles. (http://www.engravingdragon.com/EV4U)

Ready for restoration and electrification

Is this your first EV ?

This is the first one that I’ve owned personally.

What made you decide to go with the VW ?

We were looking for a marketing/promotional vehicle, and decided on the Bug because few cars have the nostalgic sex appeal that the Bug has.  Plus I was very familiar with the Bug, after years of working on them back in the 70’s and early 80’s.  This is actually the first Bug I’ve owned in 25 years.

What separates B.O.B from other EV Bugs ?

B.O.B. was engineered to be an electric vehicle.  An overall design and testing that few others have done.  Our weight distribution testing, braking, handling, etc. were all done in a very scientific way, to insure that the Bug would out perform its gasoline counterpart.  Our design is simple and reliable, and the proof is that there have been no issues with the car since we turned the key the very first time.

How heavy is B.O.B. ?

The conversion, including suspension and conversion components added 920 pounds to our 1660 pound starting weight.  B.O.B. now weighs 2580 pounds.

Front battery box containing 4 Trojan 30XHS batteries

Tell us about your lead acid pack, roughly how far does that get B.O.B. ?

Due to space and weight limitations, we are using 12, twelve volt batteries.  (At the time B.O.B. was being designed, Lithium Ion added over $12,000 to the cost of conversion.)  We’re using Trojan 30XHS batteries (66 lbs. each) which are 130 Ah at the 20 hour rating, making the pack 18.7 kwh.  The range is 30 to 50 miles.

Was any additional cooling needed on the controller ?

No additional cooling is necessary.  The heat sink used is twice the size recommended by Curtis.  Testing showed it running well within specs.  However, we added two brushless DC fans to add an additional cooling factor that equates to greater longevity for the controller.

What kind of braking system did you use ?

We did extensive testing of the vehicle while it was gasoline powered.  We used bags of concrete to simulate battery weight.  It was determined that front disc brakes were necessary, but we also added rear discs for an added margin of safety.

Preparation is everything

Does the car have a steering assist ?

Not necessary.

How many shows have you taken B.O.B. to ?

B.O.B. was been to shows both before and after restoration.  B.O.B. has made appearances in Hayward, Cupertino, Santa Clara, Fresno, Sacramento, Anderson, Redding and Chico, California, as well as Bend and Portland, Oregon.

What awards has B.O.B. won ?

He has won awards for Best Engineering and for Custom and Prototype classes.

Is the 90mph top speed quoted tested or an estimte ?

All of quoted specs. are actual.  B.O.B. has been to 90 MPH more than once and is routinely driven between 65 and 75 MPH.

Do you have a favorite story about building or driving your EV? I have lots of stories, but we can save those for another time.

What do you think the most critical part of the conversion process was ?

Research!!!  It is important to do your homework, understand the big picture.  This is a must in order to have a clean, safe, reliable conversion.

B.O.B. helping Richard EVangelize

What events have you taken B.O.B. to specifically to promote EVs ?

B.O.B. is driven every day with the sole purpose to promote EV use.  Every time the Bug leaves the garage it is promoting the fact that you can drive a clean efficient car without giving up anything.  I have spent hours at the Post Office, Hardware Store, Auto Parts Store and others locations answering questions and promoting EVs.  Most people have no idea how practical an EV is.

Which EV enthusiast sites do you visit ?

I find the EV Album interesting.  I like seeing what others are doing.  That’s what is nice about the EV Gearbox.

Where did you buy most of the parts ?

We purchased most of the EV components for B.O.B. from Electro Automotive.

Does any of your power come from renewables, either frompurchased offsets, directly, or home generation ?

Not at this time.

Do you have any friends with EVs ?

The EV community is a great group of folks, and I have made many new friends both that were already EVers and those that are now thinking

Look ma, no motor mounts ! :) In the rear of B.O.B. during the build.

about it.

What was the approximate conversion cost of B.O.B. ?

$20,000 to convert to electric and another 10,000 + to restore.

Do you plan to build any more EVs ?

We are, we have a Porsche 914, a Chevy S-10 and another Bug waiting in the wings  and we have been doing  repairs and consulting too.  We also have a 1946 Dodge Pickup and a 2002 Ford Think in our shop.

Who’s EVs would you like to see on EV Gearbox ?

You’ve already done my favorites, I’ll have to get back to you on that.

Thank you so much Richard for letting us interview you.

Much more info (and galleries full of photos) on B.O.B.’s restoration and conversion can be found here: http://www.evalbum.com/2535 and http://www.engravingdragon.com/EVBug.html

Sipping some juice.

The heat here in Phoenix is letting up a bit. Not enough to comfortably drive the car in the middle of the day, but early and mid-mornings have been very nice. Every morning I take the car out for a daily errand, and it’s just fabulous. What a great car to drive!

Back before I had to remove the motor, I was giving a friend a ride around the neighborhood to show him the car. I drove by a neighbor that lives around the corner, he and his daughter were in the street playing catch. As we approached, I was worried they might not know we were coming, but they saw us and moved aside and we all waved as we went by.

When we came back by, I slowed down to be sure we were all safe, and the father called out “Is that an electric car?” I told him it was, and he said that he knew it had to be because it hadn’t made any noise when we first drove by. I stopped for a few minutes to chat. He had a lot of questions about the car, and seemed truly interested. I answered them all as best I could and waved goodbye.

Over the past few days, since I’ve been driving it more, I’ve happened by him a few more times. Each time he eagerly waves and smiles. It’s great to have made a connection with a neighbor, I hope to talk to him more and maybe offer a ride someday. But the best thing is that he’s seeing an electric car driving around the neighborhood on a regular basis, and he has a positive attitude about it. I hope that it’s situations like this that will slowly help to convince more and more people that an electric car IS a viable option for some.

I’m still averaging about 325 Watt/hours per mile, which isn’t horrible, but I’m pretty sure that will get better with the modifications I’ve planned for this fall. New springs in the front, fix the alignment and replace the differential’s fluid are what I have in store as soon as the weather really starts cooling off.

There is one small thing that’s been driving me crazy, and that is a rattle coming from the rear of the car. A rattle whose source, I’ve not been able to locate. It only happens when I’m heading over bumps, so at least it’s not constant. I’ve looked for it repeatedly, driving the car up on the ramps and poking and prodding, but with no luck. It has a real tinny sound, so it’s something small, and I thought I knew exactly what it was. It sounds like one of the clamps used to compress the batteries in the rear battery box is loose. But I’ve checked them all, and they are all nice and tight.

It’s definitely coming from the back end though. The funny thing is, no one else notices it until I point it out. Then they all say something like “It’s not that bad.” They’re right, it isn’t, but it drives me nuts. I’m going to have to drive up the ramps again and really give the back end a thorough inspection. I’m not worried that anything is going to fall off or come undone. I used self locking nuts on all the connections in the car; the kind that can’t spin off on their own. Eventually I’ll find it. I just hope it’s before I go mad.

I’m going out to the Diamondbacks baseball game tonight with a friend. I’d love to drive the car there, but the heat would make that an unpleasant drive. The real sad thing is that the ball park has removed their electric car parking spaces! They had 2 spaces in one of the closest parking structures, right up front, with charging stations and everything. I called to find out if they were still there and what was involved in using them, only to be told that they’d been removed. Sadly, the last time I went there, I found they had indeed been turned into handicapped spaces. *Sigh* I can’t really blame them, they were empty every game, but what lousy timing!

Thanks for letting me post this Tim :) great stories.

Name, Age, Location ?

Thor Johnson, 35, Atlanta, GA

Primary occupation ?

Electrical Engineer / CTO

Its not necessarily just the green aspect you’re interested in with electric cars is it?

Yes, I like the idea of being able to choose the power source for my car (and not be locked into oil from the middle east), but the existing “green” cars were too much to stomach:

1.       NEV – Limited to 30 MPH, and usually only have 30 mile range…. I live in Lawrenceville (NE Atlanta) and  work in Kennesaw (NW Atlanta).  With a NEV, I wouldn’t be able to even make it there, much less make it back.  And limiting the speed to 30 MPH would kill freeway operation so I couldn’t even run downtown to meet my friends in the city!

2.       Prius Gen 1 – Still a gas-eater, and when running in electric mode, anemic.  For much of my driving I’m not even sure it would do as well as a normal gasoline car since the majority of my mileage is highway driving.

Our stated motto is “Purveyors of Proper Electric Vehicles”; this means that the default goal in a conversion is to not change your relationship with your car:

A.    It will have similar or better performance compared to the original car

B.     It will have adequate daily range (our target with the Boxster is 100 miles)

C.     All systems will work (including power steering and air conditioning!)

Is this conversion your first of its kind ?

This is the first Lithium conversion we’ve undertaken. Mac Quillian has done other conversions for the DOD at Warner Robins ALC. From this, we are creating plans for future Boxster conversions as well as finding ways to step-up the quality and performance of the conversions.

The next steps are to find like-minded individuals and propose custom conversions for them, keeping with the ThormacEV motto.

Why did you choose the Boxster as your starting point ?

We chose a Boxster because we deemed it a worthy car, and we loved the idea of a sporty convertible electric vehicle. For the range we desired, the amount spent on the conversion would be close to the same regardless of whether we started with a Corolla or a Boxster, so we chose the sexier, more sporty option.

What where your goals for the project, was range your top priority ? how did you balance this with other concerns or aims ?

The funny thing about range vs performance is that when you get to the amount of energy required to move the car 100 miles, the performance almost comes naturally. With our 400V, 32 KWh battery pack, we can draw 100-300A (40-120 KW) without too much strain on the batteries.

Our other concern is that the car be Proper; ie, the rest of the car works properly. The AC, power steering, convertible top, and spoiler all work on the car. We did not want to be stuck in Atlanta traffic sweating because the air conditioning was a “waste of energy.”

Where did you source the majority of the parts ?

Our components come from several places to get the best performance value that we could muster. As we innovate and design our own parts (for example, the accessory drive/transaxle mount that you see in the picture), we expect to sell our parts to others who want their conversions to “just work.” Our batteries are from EvComponents; they are Thundersky LiFePO4 cells.

During the conversion process how did you anticipate and deal with the possibility of added weight ?

The electric drivetrain adds only 300 lbs to the Boxster. We have made it a point to keep our conversion aligned with the spirit of the Boxster (low polar moment to enable quick handling, etc).