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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.
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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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Perhaps the challenge is the CRX is mostly thin sheet metal with a few folds. It's not a sturdy car so cutting to the "subframe" is pretty much cutting out the entire rear of the car. My plan is to use the subframe along with some of the existing sheet body.
But of course there is no subframe. There are structural rails integrated with the body, consisting of the floor panel with a U-shaped rail welded to the bottom of the floor to form a box... one down each side, and one across at the lateral location bar. When you cut out a large portion of the floor between the structural rails, you need to provide a replacement for the shear panel effect of that floor - that can simply be a flat replacement for the original dropped floor if the entire battery fits under the cargo floor level, and will presumably be the battery box and frame in this project.
 

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Just realized no matter which way I flip the 40kwh gen4 modules, they'll remain the same lol View attachment 133218

The diagram I made only works for 24 kWh so I'll need to replan how I'll run it.

Current plan for reference would only work for 24kwh modules:
View attachment 133219

Thinking about... It'll probably work if I reverse it...
Frustratingly true - flipping single Leaf modules is useful, but flipping a pair that are bonded together in opposite orientations does nothing. Others have built interesting conductor bars to connect modules are required despite unwanted terminal locations.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #524 ·
Was sick for a few weeks so couldn't get back to the car until yesterday.

Batteries from AliExpress arrived... Pretty beaten up.

Instead of shipping a crate, they shipped 2 modules per package, each in a separate box, both taped together with thin insulation. Given each module is about 26 lbs, it got some dented corners around the framing. I complained and they sent me instructions on how to disassemble the box and hammer the shell straight again 🤦‍♂️

So beware. I'm still going through and testing them.

Here's the packaging
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Inside the laughably thin foam
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Dented corners
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The cells appear to be fine so far but I'm still testing.

As usual in order to charge or discharge, we should always ensure the modules are compressed.

So I built out the 12 module horizontal pack.

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Currently charging and discharging to balance the packs and will see how it fares.

Separately, I installed the subframe. Will work on the battery frame next week.

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #525 ·
Misc bad fried battery modules pictures.

So those who have followed along are aware I fried a set of batteries. Well I never did get around to unpacking them, the modules that are bad or fried.

So since I have a new set of modules, I needed space so I started to unpack the bad modules and the entire thing expanded

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They had expanded so much the shells just came off

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Makes me wonder if I can reuse some of these shells for my other pack...
 

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That sucks!
IMO the modules in the 3rd pic are DAMAGED not just dented. (I'd complain more)

Be careful with them swelled cells. IIRC the "gas" that's causing the swelling is flammable &/or explosive.

Yes, if they fit, re-using the old shells is a good idea. ;)

* Can anyone suggest how to, recycle or properly dispose of, those "bad" cells?
 

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Discussion Starter · #528 ·
That sucks!
IMO the modules in the 3rd pic are DAMAGED not just dented. (I'd complain more)

Be careful with them swelled cells. IIRC the "gas" that's causing the swelling is flammable &/or explosive.

Yes, if they fit, re-using the old shells is a good idea. ;)

* Can anyone suggest how to, recycle or properly dispose of, those "bad" cells?
This one?
Wood Gas Composite material Machine Rectangle


The shell was dented from the side and corner in a way that it got pushed up. The cells appear to be fine.
 

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P R E S S R E L E A S E​

December 12, 2022 - DIYelectricCar.com today introduced a new concept in electric vehicle batteries, the ArchBattery. Utilizing Nissan Leaf modules as a prototype of the concept, the researchers in this ad hoc group of ne'er-do-well researchers quickly discovered how easily batteries can be damaged when placed in battery boxes in a rectilinear manner.

Going well beyond Tesla's hype of mounting a seat rail on a battery and calling it "structural", the DIYEC group came up with a novel arch geometry, which has been renowned for its structural strength since ancient Roman times and since whichever came first, the egg or the chicken.

Researcher @windraver, the originator of the concept, quipped, "Not only do we have structural strength in the geometry of the arch, but we have also discovered a self-assembly method, using hydrogen gas to create the arch."

Another researcher in the group, @Electric Land Cruiser, quickly noted the powerful nature of the non-electrical energy that's a byproduct of the Windraver Process, and believes the excess hydrogen can be exploited in a fuel cell, eliminating the need for a 12V battery in an EV.

While additional refinement continues, the ArchBatterytechnology is now available for licensing to electric vehicle OEMs.

Photo:

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Nah, that's not a reason - you just need to stay away from shady suppliers who can't put a shipment on a pallet or in a crate.

That's at issue here, not the battery choice which he didn't seem to have any complaints about - at least until a cell got excessively discharged. That can happen with any pack, though.

My basic rule: kilowatts cost kilograms and kilobucks. Build what you HAVE to have and without going over original vehicle weight if you can help it.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #532 ·
That is a big bummer. I was hoping it would work out for you, as I would probably follow you down this road in several months. Guess I'll put that 30+ kWh pack back to design phase
It still might. In a sense the "box" is damaged but the cells appear fine. I'm going through and balancing all the cells and doing some analysis.... and fixing the shells as I go.

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Discussion Starter · #533 ·
Two video updates since not much changes when I'm doing the cell/module balancing. One video on charging and another on discharging with also a quick walkthrough on the equipment I'm using as well as some connectors I made to make the process quicker/easier.

Also a close up video of the modules and the fried modules I'm going to recycle tomorrow.

Charging - Battery Balancing


Discharging - Battery Balancing; Walkthrough on how, connectors, the other modules and their condition, and the bad modules I'll be recycling

I took a week off from work next week so I'll be putting all my time into finishing this car :)
 

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Discussion Starter · #534 ·
Small update.

Started the vertical stack
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I need to cut the threaded rods still but this is effectively how it should look:
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I also need to add brackets/loops so that I can lift the pack with cherrypicker.

Some of these modules were dented as well and one was bad enough for me to disassemble.
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Just pop out these tension locks
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Theres 4 of em
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And you generally can easily lift it off.
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And then hammer straight whatever you need. and inspect the cells while you're at it.


disassembled view
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Reassembly is just the reverse and its just pops back in
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And now I've started balancing the next stack.
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The shell was dented from the side and corner in a way that it got pushed up. The cells appear to be fine.
Good to see that cells look good, and you're straightening out the boxes containing the cells. It seemed from the earlier post the cells were bent, but maybe I'm not familiar enough with the modules. How do you know the cells are still good even with all the bending on the outside metal?
 

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Discussion Starter · #536 ·
Good to see that cells look good, and you're straightening out the boxes containing the cells. It seemed from the earlier post the cells were bent, but maybe I'm not familiar enough with the modules. How do you know the cells are still good even with all the bending on the outside metal?
You can generally see the cells if you look in the side or if you open them up. Also if the cells had issues they'd leak or smoke.

So sequence I'm doing the poor man's approach of:
  • External visual inspection
  • Open it and internal visual inspection
  • look for leaks or smoke
  • Check voltages when charging and discharging for irregularities or imbalance
 

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Discussion Starter · #537 ·
Continuing charging and a little bit cautious about this particular module since it's a bit more imbalanced than usual. The delta is usually at most 0.01 and given what fried my battery last time was 1 bad cell, I'm highly cautious this time.

Measuring instrument Gas Machine Display device Temperature


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I'll charge and discharge to try and get the cells to match and continue observation even if I install it.
 

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Definitely mark the cells/modules that have an imbalance in case issues crop up in the future. Mis-balance could be a sign of damage. Also, you could measure the internal resistance of the cells to see if they are significantly different. I've read that's a thing you can do on the internet but I'm not sure how it's done.
 

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Also, you could measure the internal resistance of the cells to see if they are significantly different. I've read that's a thing you can do on the internet but I'm not sure how it's done.
The IR measurement should be done with a 4 wire 1khz Ac internal resistance meter. This is what the factory would use. You have two probes with two contacts on each probe. On the meter I use (YR1030+) the contacts are spring loaded place the contacts on the positive and negative posts apply equal pressure and it will give a reading. I believe that you would need to divide by the number of cells in parallel. Since an early Leaf module are 2s2p you would measure each 2p group. If there is a published IR range for the leaf modules compare the reading to the that range.
There is another method dc voltage drop. The Icharger 306b may give you the IR it would most likely be done with the DC method.
Later floyd
 
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