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

57275 Views 636 Replies 23 Participants Last post by  remy_martian
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.
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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.
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Edit (2021-12-23):
Project has begun; Battery Dropped; still need a machine shop to make parts.
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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.
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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.
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Edit (2022-12-27):
Battery Box is built and now revising the bus bars and BMS connections to the latest design.
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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.
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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #561 ·
Did some grinding and test fit.

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Since these modules will have bars going horizontally, these brackets I ironically needed in the past are now in the way. They don't come off easily and I don't have alternatives so I cut them off
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To cut them I disassembled each module that had the bolt brackets.

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And chop chop
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And now nothing is in the way and it's all clamped down.

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Welded the top brackets yesterday as well.

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Clearance is good
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Now I'm going to start working on the bus bars, BMS wires to connect the terminals and all. Goal is to do a power test after I get it all hooked up and verify this car still runs lol. And test these modules as well.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #562 ·
Started off with numbering the BMS connections again

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Then constructed the terminals for the new stack

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Went ahead and put the connections onto the other stack as well.

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Might or might not keep the heaters. I'll think about it.

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This is going to take awhile to transfer them all

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Going and going

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And I'm "done.

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I need to figure out how to cover/insulate the right side. I'll figure that out tomorrow since it's now past midnight just doing this.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #564 ·
Modified the covers a bit and covered the terminals

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A little electrical tape to secure it. Some of it clips to existing clipping points.

Put the door/cover on
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It's a bit... Close for my comfort.

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So I added a few layers of electric tape for insulation.

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Put on sealant
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And screwed in the door
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Now I'm cleaning the inside of the car and prepping it to drop in the battery and run the electrical and junction box. Might get it running tonight. 😯
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #566 ·
Threw some paint on the box cover because I hadn't painted it yet.

And then I tried to drop it in the car but ran into issues...
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The height of the box + the cherry picker didn't have enough clearance to get the battery in far enough to drop

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When it high enough to clear the bottom, it hits the top of the car.
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So I did a ton of prying and shoving to angle the box enough to get it into the frame.

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After awhile, I finally got it in

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Bottom looks good

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To be continued...
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #567 · (Edited)
Before putting in the top stack, I needed to attach the wiring for BMS, conduits, service disconnect, junction box, etc. This ended up taking the rest of the evening.

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First the junction box and connector is quite long and difficult to disconnect/connect if it takes up the entire width of the back. So I disassembled it.

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And did so again (in case anyone is wondering, today I learned this black box was a ferrite block supposedly for reducing EMI). I'll run conduits through the ferrite block instead which will allow me to change the angle from junction to connector.

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And then got distracted by the service disconnect and worked on that and laid out the rest of the parts.

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At this point it's 1am and I can't do anymore cutting or grinding (I tried to hand saw some steel quietly lol) so calling it a night and hopefully it'll be ready to test tomorrow night.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #569 ·
Started the day by mounting the plug, junction box, entry points for the conduit, and the ferrite filter. Minor detail, there are spacers under the junction box to lift it up about an inch. Just in case.

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Then I ran in the conduit.

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Mounted the conduit so there's no chance it'll be affected by the suspension. Exhaust pipe used to pass this way.

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trimmed it shorter. wrapped it and cleaned everything up.

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I used to have a thick cover that went over the spare though it was a bit long so I cut it short and dropped it in. makes it easier to connect the conduits to the battery and not worry about stepping on any parts or stuff.

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Time for the next battery!
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This one was also a tight fit but it was easier.
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A little prying and I was able to get it into the frame

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Wired up the BMS and it turns out some wires weren't long enough so I had to cut some electrical tape.
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to be continued.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #570 ·
With everything wired up.... I did a power test and it worked.


BMS Leafspy output
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The delta isn't too bad. I'll need to balance it further.
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Then I cleaned up the wiring.
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Plug it in for slow charge to balance it.
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Charging at 1kw
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So far it's charging decently.
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I'll keep monitoring and will clean up the garage tomorrow.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #572 ·
Current battery balance.

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I need to do research on what's "normal balance" levels for a Leaf. I now get uncomfortable when I see cells that are lower than the others.
 

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Discussion Starter · #573 ·
Cleaned the garage a bit. And since I added so much metal to the car... I wanted to know how much it weighs now.

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Note that no one is sitting in the car this time. New weight with box/subframe (12/30/2022)
For reference, old weight 6/3/2022 (no driver):
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That is a 148lb weight gain from all the steel I put in.

Nissan Leaf 40kwh curb weight is 3483 lbs. I'm still ahead by 989lbs. 😯

Took it for a test run. It started raining.

Rain washed off most of the metal dust that was covering the car.
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BMS after the drive:
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Car feels different. It hugs the road now since the weight is more centered. Since its metal mounts instead of wood, everything feels super solid. All the bumps don't seem to phase the car at all and it doesn't feel like the car might break from a bump in the road like it did before. Overall, feels and drives very solid now.
 

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Inspect your axle welds for cracks after loading them like that at high speed, assuming you still have the home-welded ones. You'll do a lot of damage if they let go...your next big spend should be having a set made.

Congrats on getting her back on the road again.
 

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Discussion Starter · #575 ·
Inspect your axle welds for cracks after loading them like that at high speed, assuming you still have the home-welded ones. You'll do a lot of damage if they let go...your next big spend should be having a set made.

Congrats on getting her back on the road again.
I have 2 sets of axles and still need to get a machine shop to machine me some. The welds are still solid even after flooring it a few times. I inspect them pretty often out of fear and concern.
 

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Discussion Starter · #576 ·
Made a cover today for the battery.

The "inspiration" for this cover actually came from the Nissan Leaf. While I was taking apart all the parts, I discovered that they used plastic corrugated boards with carpeting on it for the rear. And I thought wow thats much simpler than using wooden sheets.

A separate inspiration was some random youtube video where someone used PVC piping, to make a clip/holder for the PVC pipe itself.

So armed with these two ideas, I made some covers for the rear.

Here you can see that the PVC pipe adds structural integrity to the board, while also it becomes a clamp/screw point.

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A bit rough but the idea is there.

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The black carpet is sold cheap at walmart. I had some from my original covers I built for my CRX. Also had some left over 3M spray on adhesive which I used to attach the carpet/fabric to the boards.

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Spray it on. Wrap it around the sides, and it'll just stick.

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Two pieces to cover the battery. One above and one in the cargo area.

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The front board was what I built originally using wood. I just attached it back there again.

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I attached it in a "clamp" style with a screw to lock it in.
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to be continued...
 

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Discussion Starter · #577 ·
This cover goes over the actual cargo area but the LEDs weren't working anymore due to bad/cheap plugs I had used. I took the chance to repair and upgrade it.

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Some cheap LEDs I soldered back when I was in college all held on with hot glue.

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These connectors needed to be replaced. I picked these from rusty broken cars over a decade ago (most likely from the brake cylinder level sensor) back when I couldn't afford proper wire connectors.

Once fixed, I put it back in.

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I swear the lights are white but it shows up blue in the pictures.

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Also here is how the cover works

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I like the cover. Gives it a nice-n-clean look :)

IMO some thin metal should have been incorporated into the cover, to provide a bit more protection
..."if" (Heaven forbid) a thermal runaway situation ever occurs
...& give you a little bit more time to "abandon ship"

Sorry, not trying to be negative (-)
...but, while reading thru the post, that "red flag" popped up in my head
 

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You may not know this, but PVC gives off chlorine gas when it burns, and urethane gives off cyanide, iirc ("smoke inhalation" is how fire deaths are described when it more likely is gas poisoning)....not a great choice in a passenger compartment to cover something that does catch fire on occasion. You need time to stop the car and get out. I went on a rant a few months ago on a guy who was trying to sell plastic battery boxes here (because they're "easy to fab") for use inside VW Beetles.

A battery box should be enclosed in metal....yours has no top to it so far....
 
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