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Discussion Starter · #1 ·
I have been working on my car for a while and using this forum as one of my primary references. I thought it was about time that I posted my progress and documented my build.

Donor car: 1990 BMW 325i
Voltage: 156V
Batteries: 13 12V AGM Lead Acid
Range Target: 30+ miles
Top Speed: 70+mph

I bought the car in February, but didn't really get into the build until September. I spent the time from February to September finding parts and designing some of the adapters, couplers, etc.

I am going to be attaching quite a few pictures. Below is a pic of the car as I got it, without the engine. I cleaned up the engine bay and removed the sound deadening material.
 

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Discussion Starter · #2 ·
Motor Adapter Plate

I bought some recycled 1/2" aluminum plate off Dr. Bill that had vulcanized rubber on one side to use for my motor adapter plate. I did some calculations and 1/2" aluminum is plenty thick for the stresses it will be seeing. I am also going to be using a couple pieces of 3/4" thick aluminum as a spacer to complete my adapter and put the motor where it needs to be with respect to the transmission.

I attached the drawings I made for the plate and the assembly.
 

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Discussion Starter · #3 ·
I am going to be keeping my clutch. I would like to autocross this car just to raise some eyebrows so I want to be able to make quick shifts if needed. I had the flywheel lightened & ring gear removed by a machine shop. I wish I had weighed it before I took it in, but too late now.

I wanted to maintain the pilot bearing that the end of the transmission shaft slides into to ensure the transmission and motor are aligned properly. The problem is the pilot diameter in the Warp 9 motor is not the same as the pilot on the BMW crankshaft. I found a bearing with an OD the same as the Warp pilot diameter, but it didn't have the same ID as the transmission shaft. I found a some tubing that had the same ID as the transmission shaft and an OD that would fit in the bearing. In the end it all fit very tight and there was no slop.

I had my motor coupler machined out of 4130 at a local machine shop. The 1/4" keyway should be sufficient with a 1/4-20 set screw to hold it all together. I also made a spacer to position the coupler the correct distance from the bearing on the electric motor. I found that a coupler for 1" copper pipe has a 1.125" ID which matches the motor shaft. This setup allows the clutch force (only ~400lb) to be transferred to the drive end bearing instead of the shaft. The clutch will hold the coupler in position from the other side, so all the set screw does is keeps the keyway from sliding out.
 

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Discussion Starter · #4 ·
Motor Bracket

I decided I wanted to keep the existing motor mount points and mounts that BMW used. To do this I made a bracket that bolts onto the front of the motor at one end and bolts to the motor x transmission adapter plate at the other end. This ended up being a more complex project than I anticipated, but it should work out well. I did not want my motor to be rigidly mounted to the frame of the car. By keeping the motor mounts it is somewhat isolated, just like the ICE was. I also took this route because I don't completely trust the band clamps that others use to hold the motor in place.
 

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Discussion Starter · #5 ·
Motor Fitment

One issue I ran into is the placement of the motor. My goal was to have the motor positioned so that the transmission was in the same place and at the same angle as with the ICE. When in this position the Warp9 blows right through the power steering rack and the subframe/crossmember. The interference is ~80mm (3"). The power steering rack sat higher than the crossmember so I decided to drop it down ~.5" to put it at the same height. This would allow me to position the motor closer to where I wanted it, but it would still be at a slight angle. After test fitting the motor I do not think the angle difference is going to be an issue with the u-joints on either side of the driveshaft. To drop the power steering rack i cut up the brackets, bent them down and then welded filler plates back in. I don't even think it will affect my alignment, but I'll check before I get the car on the road.
 

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Discussion Starter · #6 ·
Controller & other parts

I decided to go with the Logisystems 156V 1000a controller (refurbished). I hope it works when I get around to hooking it up.

The motor I am using is the Warp9.

I also attached some pics of some misc electrical parts I got in the other day. Westach voltmeter and ammeter, cheap vacuum pump from Surplus Center (http://www.surpluscenter.com/item.asp?UID=2008111217250165&catname=&qty=1&item=4-1801), shunt, 500A fuse, relays.

The vacuum pump is for the power brake booster. I'm not sure if this pump will be sufficient, but it was 10x cheaper than other pumps out there and thought it would be worth experimenting with. I may run 2 if it can't keep vacuum built up for the brakes.
 

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Discussion Starter · #7 ·
Batteries

Right now I am waiting on some parts and trying to figure out what batteries I am going to use. I wanted to use LiFePO4 but they are not going to fit into the budget right now so AGM will need to work. I did not want to worry about adding water to flooded batteries, and need to mount a few on their side. I also don't want to worry about high discharge rates of 5C+ for short periods.

I plan on putting 4 batteries under the car where the gas tank was, 5 or 6 in the trunk and 3 or 4 in the engine bay.

Here are the options I am looking at right now:

Exide MC31
Deka 8A31DTM
Deka 9A31
Trojan 31AGM
Optima SC31DS

All the batteries are group 31. All of them have a capacity @ 20 hr of ~100AH, except the Optima (75AH)

I'm also still working on choosing a charger.
 

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great job
continue posting pictures ^^
 

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Nice work.

I like your solution on the input shaft bearing. Do you have details on the part#'s used? I'm using a bushing and a bearing would be better but ran into the same issues you did.
 

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Discussion Starter · #10 ·
Nice work.

I like your solution on the input shaft bearing. Do you have details on the part#'s used? I'm using a bushing and a bearing would be better but ran into the same issues you did.
Here are the parts I used, they were from Mcmaster-carr:

5905K23 Needle Roller Bearing, 1/2" shaft, 11/16" OD
8859K33 Brass Tube, 1/2" OD

I have a few pieces 1' long pieces of the tube left. If you want one PM me.

I would recommend using a bearing for transmission pilot. I don't think a bushing is going to cut it.
 

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Here are the parts I used, they were from Mcmaster-carr:

5905K23 Needle Roller Bearing, 1/2" shaft, 11/16" OD
8859K33 Brass Tube, 1/2" OD

I have a few pieces 1' long pieces of the tube left. If you want one PM me.

I would recommend using a bearing for transmission pilot. I don't think a bushing is going to cut it.
Thank you. I like the bearing concept. I'll research the part#'s you gave and ensure that my input shaft is the same dia. I think it will be.

A bushing should be fine. Many of the cars I have owned in the past has pilot bushing from the factory and not pilot bearings ('83 GMC s-15 being one of them). Being electric it'll use the pilot bearing even less due to there not being a need to idle with the clutch in.

Maybe if we all keep doing these swaps we can come up with a best practice for these things :D
 

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Discussion Starter · #14 ·
No progress in 3 months due to buying a house, moving, work, travel, cold etc. Finally getting started again. I still have not purchased batteries, but found a report that concerned me about the Deka Intimidators:

http://civic-ev.blogspot.com/2008/07/visiting-synkromotive-and-learning.html

The concerns are with cycle life. From an initial purchase cost standpoint these are the best choice I have found considering my budget for this project. It looks like the issue with these batteries is when they are highly stressed repeatedly. In my application the daily DOD will probably only be 40-50%.

Conclusion: I think I am sticking with the Deka Intimidators.
 

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Discussion Starter · #15 ·
I bought the batteries, so now I have started designing the battery trays. I plan on putting 4 batteries in the engine bay, 4 under the car where the gas tank was and 5 behind the RR seat in the trunk. That should give me decent weight distribution. After I finish I will put the car on some scales and see if any batteries should be moved. I have preliminary designs for the trunk and gas tank trays as shown in the pictures. I will probably build them this weekend out of 1x1 steel angle. Aluminum would be better, but I wanted to weld everything together and I am not setup for Al.
 

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I bought the batteries, so now I have started designing the battery trays. I plan on putting 4 batteries in the engine bay, 4 under the car where the gas tank was and 5 behind the RR seat in the trunk. That should give me decent weight distribution. After I finish I will put the car on some scales and see if any batteries should be moved. I have preliminary designs for the trunk and gas tank trays as shown in the pictures. I will probably build them this weekend out of 1x1 steel angle. Aluminum would be better, but I wanted to weld everything together and I am not setup for Al.
I'm surprised only 4 in the engine bay. What made you decide to go with only 4?
 

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Discussion Starter · #17 ·
I'm surprised only 4 in the engine bay. What made you decide to go with only 4?
My primary reason is weight distribution. I want to achieve a 50/50 balance and keep as many batteries as possible within the wheelbase. After I get all the batteries mounted I am going to weigh the car on some 4 wheel scales and see how well the car is balanced. At that time I may shift more batteries to the front and the battery racks will be designed to accommodate this.
 

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My primary reason is weight distribution. I want to achieve a 50/50 balance and keep as many batteries as possible within the wheelbase. After I get all the batteries mounted I am going to weigh the car on some 4 wheel scales and see how well the car is balanced. At that time I may shift more batteries to the front and the battery racks will be designed to accommodate this.
I'm interested to see how the weight distribution turns out. I've put 7 up front on mine and it does not seem overly nose heavy (I don't have the back bateries installed yet). I was wondering if I should have put 8 up front. I guess I should finish installing and then weigh the thing. If it weren't so cold outside I'd be more motivated :mad:

Keep us updated on your progress.
 

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junk yard jesse,

i am bored at work and need some updates on you car hahaha!!!
we were talking about you the other day because we had to dig up the bike pkg studies in Togo from way back in the day.
your cube is still empty but I think lou tericic is going to take your place.
i also stole your "this cubicle is so f'n small" sticker.
 

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A guy local to me hated his Dekas, he had very poor range, and asked for help. We found he had some batteries at 12 Volts and some at 17 Volts! All the front batteries were 17 Volts, and all the rear ones 12 Volts, maybe it was a temperature thing. Amazingly, the batteries survived. We had him charge up the low batteries individually, he got some regulators put on, and life was good after that. So the moral of the story is use regulators! Checking the battery voltages individually once is a while would have been a good idea, too.
I have decided to go with the Deka 9A31 batteries. I found a local source that will sell them for $170 each.

DEKA 9A31
 
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