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Introducing our 1987 Porsche 924S EV Conversion

15531 Views 88 Replies 17 Participants Last post by  lordmundi
I've been lurking on the threads for quite a while but want to introduce our father-son EV conversion project on our 1987 Porsche 924S (which my son has affectionately named "Perl"). We are super excited to make steady progress toward our 80's inspired EV conversion.
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I am not a Porsche guy, so I have been surprised by just how much I've enjoyed learning about the Porsche 924 and 944 and their history, not to mention the community around them and just how much people love them, warts and all.

We searched for a car for a while - our criteria being something aerodynamic, light weight, manual transmission, interior and exterior in decent shape but a blown or missing engine. Luckily, we found one in Perl!

What we have done so far - removed the engine, removed the exhaust, cleaned up the engine bay, got all of the lights working and mostly converted to LED, started rebuilding the brakes, and removed the transaxle (so that we can remove the fuel tank). It's been so much fun learning about each piece. We also 3d printed a cover for our torque tube and 3d printed a model of a hyper9 motor to assess how it might fit in the front.
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Where we are and questions we have - so we are about to invest in a motor/inverter and batteries. While I was initially thinking a Hyper9, I've recently become much more interested in the Nissan Leaf motor (I think it will fit better in the engine bay and will be much more affordable). If we do go with the hyper9, i think we would need to shorten the drive shaft to let the motor fit behind the front cross-member of the car, which isn't a huge deal but not super fun either. But in terms of the Nissan Leaf motor, I've been researching and trying to understand options like the openinverter project, and the thunderstruct VCU etc. My issue is every time I search for things on the leaf motor I see tons of threads and videos and I'm not sure what the more recent advice is. I know that so much development has been done in the last few years I guess I'm not sure on what the most current experiences are in dealing with a leaf motor, and what batteries and controllers are being used. Maybe my google-fu is just poor to find the most recent stuff.

Along with trying to find that information (mainly to just give me confidence to go make some purchases), I'm also a little curious about people using batteries with the leaf motor. The specs I'm reading say that motor normally runs with high voltages - something like 350 - 400V from the leaf batteries. How are people generating voltages that high? Are you forced to use the leaf batteries so that the voltage is that high? Or is there some way to use tesla battery modules and not require an insane amount of them in series? I guess I'm just looking for any experiences people know about in terms of what battery packs for an leaf motor EV conversion look like.

Other problems I haven't sorted out in my head yet - how can I at least get enough heater capability such that you can defrost the windshield (which is a safety issue)? Also, if I put a large amount of weight in the rear of the car (more than the weight of a full gas tank), can I just buy stiffer or adjustable shocks?

If anyone has any advice or insight we would love to hear it. We are really looking forward to learning and making memories with this project and hopefully sharing it with everyone else.
  • Our automotive skill level: moderate (I know my way around cars a bit, but haven't ever restored a car from top to bottom)
  • Electricity skills: I have a background in electrical engineering, although I know just enough to be dangerous.
  • Range goal: just something reasonable for driving around Houston. I think if we can get 100 mile range that would be great
  • Performance: nothing insane. Just something fun to drive.
  • Money: whatever it reasonably takes to get something working and make memories with my son.
  • Parts we are considering: Nissan Leaf motor. Not sure on batteries.
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When you say "I just learned", please cite your source. The context and credibility of such expensive remarks by a third party need to be assessed.

I think it would be good to have a written summary with each posting that provokes watching the video.
I'm not sure how wise it is to run it at high speed, unloaded...why do it at all beyond a few dozen RPM?
That's a live, open HV battery pack.

Nitrile gloves can have pinholes and wearing shorts and shortsleeve shirts (I assume your clothing is 100% cotton - if not, it will melt and stick to your skin, transferring latent heat to a burn) in the event of an arcflash, is a bad idea.

You got away with it, but if the next person who watched your video doesn't, the lawyers could come knocking.

That pack can still be deadly with the contactors off, so make sure younger kids or your son's friends can't get near it. Surprising they didn't ship with the cover over the battery, as it risks shipping handlers.

Also get yourself a clipon meter lead - very very bad idea to bridge your arms across a high voltage you're measuring. Only one hand should ever touch a live circuit or power source, NEVER both. You're again demonstrating this to anyone that views your video....people with no technical clue want shortcuts to not paying $5/gallon for fuel and that means copying what they see in Youtube videos.

Sorry to be a nanny in all this, but it seems like you don't know this stuff.
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Congrats on First Spin.

Safety tip - do not touch (or bring any metal tool near) any live high voltage cable or connector that you think is insulated with your bare hands like you did near the end of the video -- it shows you are too comfortable around the setup to where talking with gestures is not overridden and that's a ***** (c h i n k is the new of two censored words that I've discovered on this site) in the armor when a fatal accident can happen.

That (clever) HV lawnmower battery stack will still kill you as dead as powering it off mama's clothes dryer outlet.

Good luck with shadowing the bench setup.
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