[Tahoe Tim]

I thought it would be a good time to start my build thread since I am well into my build. It is a SMALL twin motor setup in a very light car to eliminate the need for a shifter. Electrically operated two speed with electric reverse. This elaborate setup is more to satisfy my curiosity with electric cars and not meant to be an economical build. I felt that I can put a twist on the drag car dual motor setups to make a clutchless and shiftless electric car that anyone can jump in and drive. We will see...

Stats:
Wombat fiberglass body on a VW frame
Projected weight = 1800 pounds

Motor and Controller = Twin 7 inch Warp motors with Warp Drive controller

Contactors = (1) pos, (1) neg, (3) series/parallel, (4) forward/reverse, all EV200 with aux contacts.

Batteries = 48 CALB 100AH lithium

Charger = ?

BMS and car controls = MOCOSO car pc with touch screen interface to a fusion brain and aux boards. Digital outputs controlling headlights, flashers, running lights. 13 analog inputs to monitor 12volt groups (4 cells) of the pack and one channel for chassis 12 volt battery.

I want to thank everyone on this forum for helping me, especially a couple of you that helped me privately.

 

[Tahoe Tim]

A little history to start it off:

VW with body removed

Restored frame ready for body

We are building a kit car AND an electric car at the same time. Some of our guys are thrashing on the car doing brake lines, chassis wiring, door hinges, etc., while others are working on the electric car systems.

A shot of the rear of the car with the first motor plate bolted up to the VW. The plate looks huge but scroll down and you will see that the plate was filled up pretty quick.

This is the bare front motor plate mounted to the VW transaxle. The lower motor drives directly to the trans and the upper motor will belt drive to the lower motor using a Gates carbon fiber cog belt. I have designed in a limp home mode if the belt breaks. Only lower motor is powered. (If the belt fails, the upper motor will over rev and be toast anyway but I still need to limp home on the unhurt lower motor). Hey, with 9 contactors I can close any combination I want, some of which will do bad things. Hence the EV200's with aux contacts to prevent any bad contact combination.

The complete adapter assembly all made up with contactors mounted on the plate. Motors and controller doing final 2/0 wiring. (I initially wired the whole think up with 18 ga wire and tried my contactor logic with a 12 volt charger to prove it out before cutting up the 2/0 cable). I'm using marine battery cable that is tinned. It is VERY flexible. This compact design took hours of thought but I ended up with a tight package and only 10 feet of 2/0 for all of the connections.

The CALB batteries came in this week!

 

[Woodsmith]

Very nice looking layout.

Any photos of the front ends of the motors?


You mentioned about the top motor being toast if the belt breaks, have you any 'ballistic' protection for shrapnel when the comm lets go? Not sure that body would stop much.
I need to think about it for mine too as the motor is sideways behind my back.

 

[Tahoe Tim]

I am installing a Netgain rpm sensor on the top motor to shut down the controller if it overspeeds in the case of a belt breakage. From what I've read here even a short overspeed will fry the motor.

I will be able to electrically disconnect the top motor from the dash and limp home on the lower motor.

 

[tomofreno]

Wow, that's quite an effort! Lot of new interesting things too. Looking forward to learning more as it progresses. How does the electrically operated two speed work?

 

[corbin]

Hey Tim -- that thing is going to be awesome!

I have a question -- what front shocks are you using? I need to drop some new ones on my bug, as they are now bottomed out with all the additional weight

corbin

 

[EVfun]

Very cool! I like VW kit cars. This one is a small light build. Especially if the Optima where replaced with Lithium.

 

[peggus]

Awesome.

One observation, the EV-200 contactors are only rated for 200A continous with 1/0 cable or 500A continuous with 400MCM cable, the cable provides the heat-sinking.
It looks like you may be using them in the motor loop with a 1000A+ controller and 2/0 cable. I'm a bit concerned you'll be melting those contactors (been there, done that).

 

[Tahoe Tim]

tom, I can't wait for our club meetings to start up again. I want to drag it in and show it off.

corbin, I bought new coil overs at www.cip1.com Read the applications carefully. I originally ordered the wrong front shocks and the wrong rear disc brake kits. I'm disc brakes all around too. They have a great return policy, answer the phone, and ship quickly. It's a little expensive coming from Canada but I like them for all my VW parts.

peggus,
I wasn't too concerned about using 2/0 because the spec sheet talks about the wire size as for heat dissipation. I seriously doubt that I'll be over 200a continuous but I will evaluate this once I get it running. I am going to use 4/0 for the controller and battery connections. Today we replace the six jumpers between the contactors (hard to see the small jumpers) with 1/4 x 1 1/2 copper bus. It looks awesome. Pics to follow...

 

[tomofreno]

tom, I can't wait for our club meetings to start up again. I want to drag it in and show it off.

Yeah! Would be great if you could get it to the one at the National Auto Museum on 2/27/11.

I seriously doubt that I'll be over 200a continuous but I will evaluate this once I get it running.

Don't know where you plan to drive it, but I pull over 200A a good part of the way up to MT. Rose summit from the east side going about 45 mph.

 

[rwaudio]

tom, I can't wait for our club meetings to start up again. I want to drag it in and show it off.

corbin, I bought new coil overs at www.cip1.com Read the applications carefully. I originally ordered the wrong front shocks and the wrong rear disc brake kits. I'm disc brakes all around too. They have a great return policy, answer the phone, and ship quickly. It's a little expensive coming from Canada but I like them for all my VW parts.

peggus,
I wasn't too concerned about using 2/0 because the spec sheet talks about the wire size as for heat dissipation. I seriously doubt that I'll be over 200a continuous but I will evaluate this once I get it running. I am going to use 4/0 for the controller and battery connections. Today we replace the six jumpers between the contactors (hard to see the small jumpers) with 1/4 x 1 1/2 copper bus. It looks awesome. Pics to follow...

Motor current is always higher (or equal to) the battery current, unless you have long battery runs I would suggest putting the 4/0 on the motor side, or both.

 

[peggus]

The other option would be to put some copper plates on the contactors and bolt two runs of 2/0 to the copper plates. That way you get good heat-sinking and you can use your existing cable and lugs.