1971 Corvette EV Conversion

[adamj12b]

OK, We have finally started this project. We have been planing on doing this for months, but haven't had time to start. On Saturday we use the truck to pull the car from down back where it was parked. We pulled it up near the garage where we spent almost an hour cleaning off all the mold and sap from the car. We removed some of the carpeting that was moldy. We had to use the pressure washer to remove all the junk. With the car clean and free from all critter nests, we proceeded to push it into the garage. we had to turn it 90 degrees CCW to be able to back it into the garage. It took out about 10 minutes to the the car in the garage as it was very hard to push because the brakes were dragging a bit. Once it was in the garage, We began the deconstruction process. We started with the simple stuff under the hood. We removed what was left of the AC dryer and its connecting hose's, then we removed the extra vacuum lines that went to the headlights, those will not be lifted with the vacuum like they use to be, so that stuff went into the box too. Next we started draining the antifreeze. Most seemed to have leaked out from sitting for so long, Only got about 1.75 gallons out. Thats all we got done on saturday.

On sunday we had a little more time to work on the car. We wanted to try and start the engine and get a little video of it so that we could sell it. We put a fresh battery in the car and about a gallon of gas in the tank. We ended up needing to add a new wire to the + side of the coil because there was something wrong with the built in one. Once we added the wire, it started right up.

After that, We finished removing the Fan and shroud as well as the radiator, alternator, belts and some other small things.

Video #1:

http://www.youtube.com/watch?v=rH1yQpbYHhM

Video #2:

http://www.youtube.com/watch?v=i-tsHDy89lw

Video #3:

http://www.youtube.com/watch?v=yB2V5py_rIs

Video #4:

http://www.youtube.com/watch?v=rsU2yw-mnFs

I also had some more time last night to get some more work done. I was able to remove both the seats, and the A/C controls in the cab. I finished removing the remnant carpet pieces that somebody used for the floor carpets. All the extra parts are cleaned out of the cargo area as well.

For the car our goals are to be able to bake the tires, as well as be able to drive it further then across town. We are aiming for around 60-80 miles per charge, but will be sacrificing range for performance. Since its a Vette, it has to be fast.

So far we have been thinking of going with 22-26 optima yellow top batteries, the D31T ones. These will be wired in series and parallel to give 150A/H and 144V. We have also been looking at lithium batteries, but we need to find them at the right price.

For a controller, I plan on building a modified version of P&S 144V open source controller. I almost have all the details worked out about it so it will be up to see soon.

For a motor we are stuck between 2 different options. Our first choice is a Warp11 motor. This will be mounted in the traditional way, with the clutch still in tact. Our second choice is 2 Warp9 motors stacked vertically, mounted into a custom made housing, coupled by 3 inch supercharger pulleys and belt. on the lower motor would be a special adaptor for mounting the pulley as well a bearing mount to support the torque of the top motor. On the other side of the bearing would be the clutch mount, and you know the rest. The 2 motors would look very nice and still leave alot of room in front of them for batteries. If we do 2 motors we could put them inline instead. As I said, were not sure what were going to do.

I believe the 2 motor setup would be a better choice, producing above 60 HP between the 2 motors. This, I believe, Would increase the top speed of the car greatly, While providing incredible amounts of torque in the low end. But, I do realize that it would have poor effects on the range of the car.

I also plan on building a BMS system from scratch. This will include modules for each batteries, as well as a central computer to monitor the packs and alert if there are problems.

Well I think thats it for now. I would love to hear your comments.

-Adam

Picture #1: Rick washing car
Picture #2: Engine bay
Picture #3: Interior before being stripped
Picture #4: Engine bay after Radiator, Fan, Shroud and Alternator removed
Picture #5: Interior stripped

P.S. I promise that following posts wont be this long.

[stevey_frac]

I was thinking about a project like this the other day!

Very interested to see it evolve. I agree as a 'vette it HAS to be fast.

Subscribed!

[robchalmers]

Great looking project I can't wait for more pics!

[AmpEater]

Originally Posted by adamj12b

I believe the 2 motor setup would be a better choice, producing above 60 HP between the 2 motors. This, I believe, Would increase the top speed of the car greatly, While providing incredible amounts of torque in the low end. But, I do realize that it would have poor effects on the range of the car.

I also plan on building a BMS system from scratch. This will include modules for each batteries, as well as a central computer to monitor the packs and alert if there are problems.

Well I think thats it for now. I would love to hear your comments.

-Adam

From a purely performance standpoint 2 motors would definitely be superior, but only if you are already exceeding the power handling of a single motor. Its more about "motivation" than how much motor you have. Twin motors won't perform any better than 1 if you're driving it all with a 500a Curtis. With the added weight probably even worse. Even a single 9" would likely handle all the peak power you're going to be able to push into it unless you're going >1000a or >200v

2 does increases your sustained output by a factor of 2, but only as long as the batteries can keep up, which isn't long enough generally to warrant it.

In terms of range I don't think 2 would effect things as much as you suspect. Most people think this way because we are so used to dealing with engines.....big V8s get worse mileage than 4 cylinders even driven at the same speed. But in EVs its all about wh/mile and 2 motors operating at 90% efficiency doesn't use any more power than 1 motor operating at 90% efficiency, unless you're pushing things so hard that the 1 motor is overheating.... The added weight is more of a concern.

If this is your first conversion I would recommend a single motor from a headache / simplicity standpoint. I really, really wanted twin motors but in the end I was glad I went with just 1, there was plenty of other stuff to keep me busy instead.

Looks like an awesome project.....keep that momentum going!

[TheSGC]

Nice Vette!

I liked the videos fast pace and also seeing the sun go done.

I think a single Warp11 is just fine. Gobs of torque and with the transmission you should have no problem showing off.

Though, you will be hard pressed to get 60-80 with Lead Acid batteries. 60 miles of range is usually the limit and that usually needs 144 volts and 240 Ah golf cart batteries, about 1500 lbs of lead.

With 144 volt 150 Ah your range will be closer to 32 miles. A Honda Civic driving Econo style will get 40 miles using 144 volts and 170 ah of batteries, so 60-80 miles using lead acid in a Vette will be hard pressed, if not impossible.

And yes, jack rabbit acceleration has HUGE effect on range, and so do these stupid MA hills!

Make sure that you controller can produce 250 AMPs continuously too. I just spent the past few days figuring out the power required for a lot of these hills, and my Kelly doesn't hold up at all, and a Curtis probably wouldn't either because of the rather high Current needed for climbing at anything above 5 MPH, (Been there, and doing that....putt putt putt up those hills...)

[Frank]

Three words: lithium, lithium, lithium.

I have 1320# of PbA in my pickup ('94 Toyota i.e. it's small) and it's a pig going up hills. I figure I could get better performance with about 400# of Thunderskys. Lead's gone up in price and lithium has come down. $1.10/AH is the best price I know of now (http://www.evcomponents.com/SearchResults.asp?Cat=28).

Imagine taking 900# out of any vehicle...

Great project BTW. Here's a couple of links that may be helpful.

Russ Reiss' 1974 Chevrolet Corvete
Michael Shoop's 1987 Chevrolet Corvette

[adamj12b]

Thanks guys for all the kind comments and advice! Its people loving my projects that gives me motivation to work hard on something to show off.

@ AmpEater: Dont worry about the controller. While Im not ready to let the details out yet, I will say its Very Capable. About the motors, Im not worried about the difficulty with mounting or wiring 2. We both are electricians as well and I have a deep background in electronics engineering. For the actual mounting part...Well I have 2 CNC milling machines and a manual lathe, as well as tig, mig, and oxy/actl welding outfits. I plan on manufacturing everything myself, From the adaptor plate and coupler down to the new digital instrument cluster.

@ TheSGC and Frank: Im hoping to use lithium even if it is a small pack, I can fit 1 string of 45 LFP160 TS's weighing in at 555lbs. Thats 3 times less then 24 optimas...and a bit more capacity. Its just shy of 8k bucks though. So I dont know yet.

@ Frank: I have seen the Volt Vette before, but did not know about the other one. Im going to be emailing him as he only lives about 1 hour away from me!! The 74 vette is also a C3 so the 2 cars are alot alike. I will see if he has ran into anything I should know about.

@ stevey_frac and robchalmers: You can check out the website @ Welcome to EVVette.com for more pictures.

-Adam

[TheSGC]

I just realized that your Engine compartment is HUGE! That will be great for adding all those parts and having room to work in.

Having you own CNC machines and milling tools will help A LOT, and same with the welding. I had to buy a new drill press for my latest adapter plate design and use a 4" hole saw to cut 3/4" and 1/2" aluminum and it was scary.

I found in my conversion, that the adapter plates and the coupling was the easiest, only second to removing the engine. The hardest part was waiting for the parts and wiring up all the little electronics, finding out that you need a few trips to Radio Shack for relays and connectors, then wiring up more.

About battery prices, 24 Optima's is about $5.1K and the same amount of lithium to get the same power as those Optima's is about$ 5.9K, so why even go with lead? You get about Half the useful power from lead acid batteries, and with lithium you get most of the power. So, in theory, 144v 120 Ah LiFePO4 is better than 144v 200 ah lead sled, due to the difference in Puekert's Effect and the difference in weight.

[adamj12b]

Originally Posted by TheSGC

About battery prices, 24 Optima's is about $5.1K and the same amount of lithium to get the same power as those Optima's is about$ 5.9K, so why even go with lead? You get about Half the useful power from lead acid batteries, and with lithium you get most of the power. So, in theory, 144v 120 Ah LiFePO4 is better than 144v 200 ah lead sled, due to the difference in Puekert's Effect and the difference in weight.

What are you looking at for 120Ah LiFePO4 batteries? Thinder sky's go 40, 60, 90, 100, 150, 160...

I would probably use the 160's. In the spec sheet there rated to 3C so thats 480A continuous, and 1600A peak. I dont think the high current pulls in the 1000A range would cause much damage to them.

-Adam

[TheSGC]

Originally Posted by adamj12b

What are you looking at for 120Ah LiFePO4 batteries? Thinder sky's go 40, 60, 90, 100, 150, 160...

I would probably use the 160's. In the spec sheet there rated to 3C so thats 480A continuous, and 1600A peak. I dont think the high current pulls in the 1000A range would cause much damage to them.

-Adam

Sky Energy (EV Components have them) and they are supposedly better than TS and somewhat cheaper, with a 4C continuous rate.