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1986 CRX EV conversion (Nissan Leaf Donor) - Now Running and Misc upgrades

56554 Views 625 Replies 23 Participants Last post by  dddrewski
I'm new and am planning to convert my 1986 Honda CRX into an EV. I have a 2015 Fiat 500e for parts but from what I know so far, the Fiat is sensitive and difficult to use for parts. I believe it uses the Bosch 180/120 based on my Google fu. I've sourced the wiring diagram for the vehicle and confirmed it is indeed a 3 phase AC motor, one for each phase, 2 wires to sense temperature, and another 6 for the resolve (excitor, sin, cos). The biggest challenge is that Fiat uses canbus and the controller, inverter, battery, and more likely will not operate without all the parts. The car almost disabled itself when I changed the radio to android auto makes a good example. I am studying how canbus works in order to see if I can either ignore errors or maybe even hack the system to work.

As back up if I have to build from scratch, I have a separate thread pending approval where I'm asking about the compatibility of the Bosch SMG 180/120 with the Scott drive 250 AC controller.

Also I'm reading I might need an inverter? And what else? I'm still digging through the site trying to figure out what are all the parts needed to run an EV with an AC motor, which seems to be more complex and less popular than running DC. So guides or hints are welcome as I learn the anatomy of an EV.
Edit (2021-12-06):
Current project is now to convert the 1986 Honda CRX using a 2013 Nissan Leaf as a donor car in combination with the Resolve-EV Controller.
Edit (2021-12-23):
Project has begun; Battery Dropped; still need a machine shop to make parts.
Edit (2022-07-14):
Car has been running since June 2022. Car has been inspected by the California Referee Station and certified as an EV. DMV has issued registration though they're still trying to figure out internally how to actually label my car as an EV.

My latest work on this build has been to upgrade the battery from 24kwh to 40kwh. Batteries are installed but I still am working out the BMS issues as a bruteforce upgrade doesn't accurately recognize the battery capacity differences.

The to-do list is on-going and always evolving so although the car is running, I'm likely to be doing some new upgrade or change all the time.
Edit (2022-10-23):
Started building a battery box which is the "final battery" box. Still in the planning state but measure many times and cut once.
Edit (2022-12-27):
Battery Box is built and now revising the bus bars and BMS connections to the latest design.
Edit 2023-01-10
Got it running on 2022-12-30. And got it back on the ground and took it on a road test 2022-12-31

Been cleaning up and doing misc upgrades since.
501 - 520 of 626 Posts

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #502 ·
Any updates on your Leaf shifter idea? id like to use the setup on my resolve ev controller as well.
All these posts below reference the shifter:

The short is the Resolve EV is looking for a normal switch so the Leaf Shifter doesn't work. I ended up hacking it apart and adding reed switches inside

At that point, you might as well put in your own circuit board with reed switches and it requires a lot of trial and error to figure out where the reeds switches should go. Also note that the magnet in the shifter is "L" shaped so you'll actually have to remove some of it and rearrange it.

My shifter works but if I was to redo it, I'd probably make a better circuit board and do more research into how game controller shifters work. Also note that the Resolve EV controller requires momentary switches.

Tagged @DaveEV since you're exploring the shifter as well.

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #503 ·
Alright, so I got out to the garage and got work done.

First I cut the battery and welded it together. Its ugly but its solid.
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Welded both sides and grinded it down.

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Test fit the modules
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And that was when I realized that the terminals are the same position no matter how many flips I do.

Stacked it up anyways and realized I didn't have long enough bolts or rods to bolt them down...

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At the very least I got a measurement of the vertical dimensions of the pack. Looks promising. It'll be less than 11.25" compressed
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Width dimensions. Probably max of 27.25" width
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For those who remember, I originally was going to vertically stack some modules upfront under the hood so I had bought some 250mm M5 rods to bolt down the modules.

It turns out I need about 285mm M5 rods in order to bolt down 4 Gen4 modules.
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For the sake of testing, I cut and welded these rods to the original bolts
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Here you can see them installed. It works okay but I don't like the fact I welded the rod and bolt together and also it reaches a bit too far below so I'm going to get some proper threaded rods to compress the modules.

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to be continued...

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #504 ·
Next up I lined up the plate and started planning out where I'd cut.

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Since I welded those ugly bolt/rods I used them to get a sense of the height.

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Here I put the tray under the car and it clears the bottom easily.

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Plenty of space.

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Plenty of space front and back
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I'm still thinking about how I'm going to bolt to this frame....
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A part of me wonders.. if I should just drill and weld a nut to the side... or maybe make a bracket that bolts to the existing holes.

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Definitely going to use those old holes that were used to hold up the fuel tank.

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Front side has some triangles that were used to hook the fuel tank to but I don't plan to use them.

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To be continued....

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #505 ·
Battery cables are in the way. So I took them apart. I usually design and plan my build so I can dissemble it which pays off whenever I change my build...
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Now I'm ready to cut the rear

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Drew some new lines... in yellow so we can't see it in photos apparently
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Cut the lines
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I was considering if I should try to bend the steel up to make a straight angle but that was too much work so I just cut it and did a test fit. The hole is too small but I'm probably going to trim the battery tray a bit.

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Probably going to trim the back since there isn't anything back there...
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The front definitely needs more room.
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I had a lot of room still to cut.
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I put on the module and a connector and we can see the front can't be trimmed.
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The back is quite clear though
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· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #506 ·
More pictures lol

The flintstone car is ready
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I trimmed it a bit more and now the tray drops in nicely
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Another angle
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I'm thinking about what kind of brackets do I want to add to so I can lift and drop these batteries...
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Next I'm going to build the subframe
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There was more room to the rear frame than I had originally thought.
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Also will need to grind down the back of the battery plate tomorrow.
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I probably don't have enough metal so likely tomorrow will mostly be planning, measuring. Maybe I'll make some brackets at most but I won't be able to build the subframe until I buy some steel. I should start with cardboard templates...

· Registered
2014 Tesla Model S 85
80 Posts
Tagged @DaveEV since you're exploring the shifter as well.
Thanks, that was very helpful. I'm struggling through the idea behind you. It sounds like each switch just added 50 ohms resistance? And always at least two switches closed. I'll have to check that out. I find it odd that the shifter doesn't work with the Resolve-EV controller.

In the end, the OpenInverter board is looking for momentary or locked (programmable) 12v(?) for Fwd and Reverse. It sounds like if I really want to use the Leaf shifter I'll have to build my own circuits with reed switches (or other). I'll see what I come up with!

· Registered
5,367 Posts
Use the holes that are already in the subframe if you can.

Not sure anyone makes the 285-300mm bolt in an M5. You can also use plain carbon steel rod (maybe powder coated) and use a threading die to put threads on each end. Stainless allthread is another option, of course.

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #510 ·
Your new battery mount looks awesome. Really stoked to see how it turns out. Have you had a chance to test the new cells at all? Even just measure the voltage? Seems like Alibaba might be a win.
The new cells from AliExpress haven't arrived yet. They're still at sea. These are the old 40kwh modules and I'm just using them to test fit things and plan. I'll have more updates when they arrive.

Use the holes that are already in the subframe if you can.

Not sure anyone makes the 285-300mm bolt in an M5. You can also use plain carbon steel rod (maybe powder coated) and use a threading die to put threads on each end. Stainless allthread is another option, of course.
I found 1 meter M5 threaded rods on Amazon. Going to cut them to size.

If I couldn't find it then I would likely have threaded my own like you suggested.

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #513 ·
Take a look at using Rivnuts...
Rivnuts looks quite promising.

Did some measurements for that purpose.

The large hole on the side beams:
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Small hole on the same beam:
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Rear holes on the rear beam above the sway bar:
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Also... PSA if you're cutting metal, cover your windows.

The sparks burned into my windows. Not sure if theres any way to clean them off other than to replace the glass...
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Otherwise, I need to buy some square steel tubes this week. Maybe order rivnuts too.

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #514 ·
Had a productive day.

Picked up some steel tubes a few days ago.
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Cut it down to fit.
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One for front, one for back
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Also picked up some threaded rods to use for the horizontal battery stacks. Turns out the bolts are actually M6x1.0 and not M5x0.8... so I had to return these rods and make a new order. The rods are about 1 meter in length so I can cut it down to size.

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Starting with the rear bar that will mount against the rear beam over the rear axle, I marked the 3 bolt locations for drilling

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gave it a good hammer with a punch to start the drilling
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These little things look so simple and seem so simple in my head but it still takes forever... The steel is quite thick so even drilling 3 holes takes awhile... wish I had room for a real drill press.

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Test fit!
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I'm happy to say the holes line up 😅

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Drilled all the way through but I'll need at least a 4 in bolt... which I don't have, to secure the beam.

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Also I'm planning to drill down from the top and secure the beam top down as well.

to be continued....

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #515 ·
I drew out a design but at this point, I looked to the side and wondered... do I go out or do I go up?
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The top still needs support and even after going up, I can still afterwards go outward... so I went up. Probably should've gotten a bigger beam but... oh well its done.
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Probably about an hour or two later, I cut and lined up the top beam of the subframe I'm building...
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Ready to spot weld. then unbolt, drop, and fully weld outside.
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Its ugly but its welded and solid. I'll grind it down and make it look better later.
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Bolted in. I expect to bolt something at the top so these long bolts will be useful later. Also I put in the front beam. I'll need another piece to drop down...
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And here they are..
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And its already dark. All the above somehow took all day. Cutting, drilling, welding. Unbolt and rebolt. In and out of the car.

Missed a few photos but I welded it together
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And its installed.
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Tomorrow, I'll need to make some beam/brackets to attach to the frame on the side. Hopefully that isn't too complicated.

If I can finish this subframe this weekend, next weekend I should hopefully be able to built the battery box that I'll drop in. And then I could actually test drop in the actual lower horizontal stack battery.

Based on the plan, I should be able to finish the entire battery box before end of year.

In other news, I got shipping notice for the batteries I ordered from Aliexpress. They're expected to be on a boat by 11/25. So hopefully arrive at port sometime in December. At that point it'll ship to home by mid December hopefully. In time for me to install it hopefully.

· Registered
892 Posts
I was just thinking, when/if you have to drill holes in steel "by hand" it makes it much easier to start off with a "pilot hole" (usually ~1/8")
...then, drill it out "in steps" a "little bigger" bit each time, until you get to the size you need
...& it's "easier" on the drill bits too (doesn't "dull them out" so fast) especially them "big" expensive ones ;)

· Registered
1986 Honda CRX (EM57 2013 Leaf Motor)
433 Posts
Discussion Starter · #518 ·
Less pictures today but finished adding the side beams.

Added a rivnut on one side since there wasn't anything to bolt to. The opposite side I was able to use existing bolt holes.

Here I had just finished welding and did a bit of grinding to soften the edges.
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Sanded down and ready to prime and paint
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One coat of paint done. I'll need to throw on another coat tomorrow.

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With this, the subframe is pretty much done and I'll now need to build the battery frame next.

· Registered
697 Posts
Looks awesome. Just make sure you have lots and lots of fasteners to spread the load from your new subframe to the cars body, these cars are like tin cans. Very thin and soft metal. On my '86 I bent and partially pulled off the panhard mount by accidentally bumping a curb in a parking lot with my rear tire at only a couple MPH.

Otherwise it looks really good! Should have a nice and low center of gravity too.

CRC drill and tap oil is really amazing stuff for that.

· Registered
8,516 Posts
I'm not familiar with CRX, but maybe there are hardpoints on suspension to support the bottom box? I'm sandwiching between subframe and frame.
The CRX has no rear subframe, and you've seen all of the suspension mounting points in the photos: one forward mount for each control arm, one bracket on the left side for the fixed end of the lateral location (Panhard) bar, and the spring and shock mounts.
501 - 520 of 626 Posts