Hey folks, I’d like to get some feedback on my current plan. As I mentioned above I’ve got my Scout up and running and I’m ready to buy a Leaf to cannibalize.
I’m planning to buy a whole salvage Nissan Leaf >2014, preferably with the Plus trim for the 62kWh battery. I’ll use the following components from the Leaf in my build: motor, inverter, battery pack, BMS, contactor/precharge circuit, PDM (slow and fast chargers, DC-DC), with an aftermarket controller.
After some discussion with the folks from Thunderstruck and Resolve-EV I think Resolve is the better option for the controller (though I’m open to input here). Their focus seems to be more on full vehicle swaps rather than just running the motor and inverter. They support comms managing the PDM, and say it should work with the gen3 battery pack with a little additional reverse engineering.
I’ve got a coupler on the way from user Bratitude. After chatting to them I think a clutchless design is going to be the way to go. My desire to retain the clutch was primarily to have a simple mechanical way to disengage the motor in an emergency (I work on software security for a living - I don’t trust software), but Bratitude pointed out that I can just pull the stick into neutral in that case. I’m not too concerned about shifting as I should be able to get close to top speed in 2nd (tho I need to do the accurate math on the gear ratios here), and it’s not expected to be a speed demon anyway. I’m sure I’ll figure out clutchless shifting. Bratitude also suggested an electrical cutoff on the PWM input to the motor controller (similar to Brian’s suggestion upthread). So I think between these I’m pretty satisfied with the non-software safety aspects with a clutchless design.
The motor and transmission will be joined directly by the coupler, with an aluminium adapter plate mating the transmission bellhousing to the motor (I'll likely buy one from user: Electric Land Cruiser over here
once I figure out if that will have enough metal to mate with the bellhousing on the Scout's trans, otherwise I’ll have one fabbed).
The coupler has internal splines for the Leaf output shaft on one side, and blank metal on the other. My options are:
- Find a machine shop that can mill internal splines matching the Scout’s transmission
- Cut down a clutch disc and weld it onto the end (this seems super janky and tough to get right)
- Find some other hub that matches the scout trans spline and attach it somehow?
For my initial proof-of-concept the whole Leaf battery pack will sit in the tray of the Scout, and I’ll figure out where they can go once I get everything going. I’d like to have a rear seat, so there’s a few options for batteries:
- Under the hood
- On top of the long, flat wheel wells that span the entire length of the tray
- Behind the rear seat
- Under the rear seat
Between 2, 3 and maybe 4 I can possibly fit the whole broken down pack without needing multiple BMSes. We’ll see when I get there.
Concerns, challenges and opens:
- Best way to get the Scout trans connected to the coupler
- Unknowns with using the 62kWh battery
- If I get a gen3 Leaf, the Resolve folks haven't had much experience there yet so I might be doing a bit of reverse engineering of the BMS comms. I'm comfortable with that, but it's something that's going to add some time. From chatting with Isak I think I'll probably have some support getting it to work, and I'll gladly feed back information from my own reversing. Alternatively I can focus on getting a gen2 Leaf with low miles, but it’s somewhat dependent on what I can find.
- I believe the Leaf inverter and PDM require liquid cooling
Any feedback? I’m particularly interested in any huge flaws in my reasoning, or big things I might have missed that I need to make a decision on before I commit to this plan, and definitely experienced input on the best way to approach the coupler situation -- bladesmithing experience has not prepared me for designing things involving real torque.
The next steps for me are:
- Buy a leaf and strip it down
- Decide on and buy a controller
- Get the motor/inverter/batteries/basic charging running on the bench with the new controller
- Pull the transmission out of the Scout (the point of no return [not really, but the Scout will sit in the carport until it's drivable from here, unless I buy another transmission or something])
- Get the coupler machined to fit the Scout trans
- Buy or get an adapter plate made
- Get the motor and trans mated on the bench
- Put it all together
Then it's phase 2: polish. Stashing batteries and figuring out whether I need another BMS, getting fast charging working, instrument panel, etc. At some point in there when it makes sense I'm probably gonna have the Scout painted (frame off), clean up and POR-15 the axles, etc. I'm loath to strip it all back down once it's built, but I also don't wanna get sidetracked with general restoration stuff and focus on the EV conversion. I also don't wanna have a nicely painted and restored Scout body that I then have to cut up to fit stuff into, so we'll see. There's some other stuff I wanna do like disc brake conversion, maybe improve the steering, etc. But that can probably come later. Anyway, lmk what you reckon! Thanks, as always for the collective wisdom!