DIY Electric Car Forums banner
1 - 9 of 9 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 · (Edited)
Hi and greetings from Finland!

I've started my 1974 BMW 3.0 CS project couple months back. Goal is to have about 250km range and all the power that you can get :)

I don't have any background on building cars nor mechanical expertise. But I have 20 years of experience in coding, so that should help with maybe some parts of the project :). So, I'm going to rely my friends shop quite heavily and help of all component sellers and of course this great community.

Bought the car from Germany without seeing it in person. Received 3 weeks later. I had a guy in Germany so he helped to inspect it and to do the deal. Car had not been used since 2001. But it was in quite good condition for a 45 year old rust bucket (as the Karman built cars are known).

Bought a salvage battery pack taken from 2017/12 Model S 75D, and a small drive unit from the same car. The car had 5000km in odometer. Some kind of fire it had. The hood had a hole just in front of the drive. But while shopping, got tempted for P85D large drive unit from the same shop and got that too. It's like 220kW or ~400kW of power .. easy choice :)

We extracted the modules from the pack with a help from my friend and my son. It was interesting to find that the seller had actually painted the "hump" in the front of the battery, because it was burnt. Luckily 75D does not have any modules there. All modules had a good charge, exactly 22,1v per each module.

For controlling the motor, I did ask from all the possible places for controller. HSRMotors does not sell controller separately. EVWest sells, but they require drive unit to be sent to them for patching. Advantics I could not reach. But luckily there was EVBMW (Damien) who sells the open source controller. So I ordered two, one for small drive unit and one for large, even though I don't probably need the small one, it's easier to sell if it has a board that you can actually control.

Couple weeks ago, I also got Tesla gen3 charger. Again, with some help of Damien (a control board for that), we should get this running at some point.

Idea is to somehow fit 10 or maybe even 11 Tesla battery modules. That would give 50 to 60 kWh capacity and maybe 250-300km of range. Problem is, that in Finland the "transformation inspection" guys say that batteries are comparable to gasoline tank, so you cannot fit batteries further than front axle. This creates a big problem.. But let's see how it goes.

As EVBMW board does not have traction control, the usual Tesla open diff solution would not work. So I ordered Quaife limited slip diff and Tesla drive unit stubs from zero-ev.co.uk.

The rest of the stuff I ordered from evshop.eu. I got Orion BMS for 84 cells. DC-DC 200v+. Main contactors, fuses, fuseboxes, etc.

As I got the car, I delivered it my my friends shop who took it a part, and took it sandblasted. Currently the car is stored in garage, while waiting for rust-fix-guy to complete his previous Cadillac project. The work might start this or next week.

After couple rust spots (floors) and roof is fixed, plan is to start mounting the drive unit and the batteries.

Plan is to have this thing running before summer! Wish me luck :)
 

Attachments

·
Registered
Joined
·
6,270 Posts
That's an interesting choice. I assume that you know about jetdexter's project: 1974 bmw cse. They're the same model, and even the same year. You might find some useful discussion and references in his thread.

It should be interesting to see how many battery modules each of these projects fits in... and where. :)
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #3 ·
That's an interesting choice. I assume that you know about jetdexter's project: 1974 bmw cse. They're the same model, and even the same year. You might find some useful discussion and references in his thread.

It should be interesting to see how many battery modules each of these projects fits in... and where. :)
Yes, that is probably the most interesting project to follow in my point of view. Very similar ideas all around and similar background. Tesla batteries and drive train. Also plans to use it daily driver, as do I :)
 

·
Registered
Joined
·
6,270 Posts
Electric Classic Cars in the UK has completed similar conversion too: https://www.facebook.com/1557620734562093/posts/2236261280031365/
I don't know if I could find that issue of that magazine in a store even if I wanted, but here's an online article about the same conversion: Test UK's only electric BMW E9 Coupé. The conversion company doesn't seem to want to share any useful information on their own website.

This conversion is apparently a traditional-layout conversion but using the old Roadster modules (or perhaps Smart modules of the Tesla generation), and a tandem induction motor pair (dual AC34/35) adapted to the original transmission. While the fluff review praises the handling, the masses of battery beyond both axle lines will not be helpful; I hope that the current projects are targeting better dynamics.
 

·
Registered
Joined
·
79 Posts
Hi ManE9,

Great to come across your post today. Yes, we may be able to share a lot of what we are learning. My car just got blasted, and I have some issues to deal with for the next month or so before I can start fabricating.

That is REALLY too bad to hear about no batteries in front of the axle. You can see from my post today how nicely they do fit in if you don't have that limitation. It seems that you will have to forgo the rear seat altogether as you may be able to only get a few of them up front (but behind the axle).

I wound up going with the 057 Technologies control unit. I searched a lot about this, and there are some great choices, but I did not want a touchscreen system- that forces me to use their touchscreen. As a coder I am sure you can appreciate wanting to create a fresh touchscreen that does much more than just talk to the motor. Besides, none of the ones I found seemed to let a graphic designer within a mile of the R+D lab. They look like race car units- which they are I suppose. So they are terrific to control the motor perhaps, but not much to look at as a daily driver. Too bad that the 057 requires it to be sold with the drive unit. I went round and round with them about that too- but I appreciate their reasoning behind it and let it go. But for you that was not an option- too bad.

Anyway, I'll be following your progress and am sure to ask you questions as you may pass me up here shortly since my metalwork issues are setting me back now for some time.

Good luck!

Paul
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #7 · (Edited)
Oh, missed couple of these messages.

Nice to hear from you Paul. I like what you are planning to do with Raspberry PI. The fact of controlling everything in the car using that with can module attached. I think I'll do the same. Coder here too :)

My project is bit stuck now while waiting for rust repairs. The guy who originally was going to do it, couldn't make it after all. Roof is quite bad, and it needs either replacement roof or real pro fixing it. One rust repair pro is coming to check the roof tomorrow.

Tesla modules are sitting in my garage. Quaife LSD waiting in shelf, driveshaft stubs, Tesla pedals, new wheels etc. Fingers itching to start actually building the car..

What else Tesla parts can be used without some serious hacking? Is cooling pump one of those, heater unit, tesla vacuum brake thingy.. Does anyone tested those?
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #8 ·
Small update. Finally found a guy to do the rust repairs. Should be all done next week. He's also taking the rusty old roof off, and putting new on. No pictures of this yet, haven't seen the car for a month now.

Meanwhile, I got the small drive unit running in garage with Tesla accelerator pedal. :cool: https://www.youtube.com/watch?v=AkpBf9Y7B6E
 

·
Registered
Joined
·
79 Posts
That's great news! Put up some photos of the car when you can, can't wait to see it. We have been working full-time on this rust for 5 weeks now and might be halfway done- so I wish I could have found your one-week solution. Perhaps it's a bunch of guys working together, versus my situation.

Keep it up!

Paul
 
1 - 9 of 9 Posts
Top