Around the start of 2021, I decided to build a "fun, capable 4WD for commuting and adventuring in with my partner, while trying to reduce CO2 emissions". My partner and I fell in love with a 2001 Jimny, so it has been selected as the donor vehicle. I started a thread to discuss the possibility. After a fair bit of throwing ideas around with the wonderful AEVA community, I reached a preliminary design: a direct drive conversion using a Nissan Leaf motor/inverter. Here is a rough breakdown of the decisions made so far and some reasoning:
- 2001 Suzuki Jimny: light, 4WD, reasonably low (for a 4WD) coefficient of drag of 0.28 according to this 1998 article, not too much difficult electronics to mess around with, and my partner and I love it
- Direct drive: Easy regenerative braking, less powertrain weight/volume without the gearbox and clutch, lower part count, can get enough gearing from transfer case (modifiable up to 1.63 in high) and differential (can swap for a 4.3) to get a decent performance curve with a final gearing ratio of 7.01, quite close to the factory 8.1 of the Nissan Leaf (credit to @francisco.shi, @jonescg, @T1 Terry, and @seth2012 for talking me gently through this)
- Nissan Leaf motor/inverter: OEM part = higher quality than a souped up forklift motor, liquid cooled rather than air cooled for more rugged design, comes with a pretty nice liquid cooled inverter (credit to @francisco.shi for the suggestion)
- Dilithium Leaf VCU: controls the inverter, saves a fair bit of implementation time (yes, the CAN has been cracked on the inverter, but this little box does quite a lot of work on top of talking to the inverter), improves reliability over my own possibly dubious embedded systems skills
Next Actions
- Wait for the Leaf motor and the VCU to arrive
- Perform a bench test with a home made power supply