Main Traction Battery Upgrade i-MiEV

[Jiminy]

Better than pictures though is the parts themselves. Height differences are hard to discern from pictures alone. I received a full module and CMU boards (minus the cells) from an eBay seller in Canada. From this, I was able to figure out what was required to make spacer washers and bus bars for the unique cells Piev is currently working with. Also, I drew up and printed out a simple 3d printed "taco" for the bottom of his cells to center those cells in the stock plastic cell holders. All with his help, of course. He has ordered a small amount of metal parts to test fit and I sent him several tacos today to test as well. If everything fits then he will order the balance of metal parts.



Jim

 

[Jiminy]

I found out that once you shave off all of the extra plastic around the seven weld points of the top web you can use M3x10 countersunk screws to reattach the top web to the cell holder. There is a cavity there and a countersunk recess just meant for those screws. Makes for a very secure hold on that part.

 

[tomhanman]

Hello,

My son has completed the "Pack Removal" section of the documentation.



https://5by9.net/prune_batteries/module_rebuild.html

Hello,

My son has completed the "Pack Removal" section of the documentation. It may be found at:

https://5by9.net/prune_batteries/pack_removal.html

Thanks,
Michael

Clearly we're all very impressed and grateful for you and your son's work (as well as the pioneers of this thread), so i was wondering if maybe your son has a name? So that he may bath in the glory rather than being forever referred to as the prodigal son.

 

[mradtke]

Clearly we're all very impressed and grateful for you and your son's work (as well as the pioneers of this thread), so i was wondering if maybe your son has a name? So that he may bath in the glory rather than being forever referred to as the prodigal son.

Yes, his name is Nicholas.

He's not looking for fame, he just wants to share.

 

[tomhanman]

Well, there's nothing wrong with sharing fame

Thank you Nicholas.

 

[program5628]

I went through this thread and made a guide. I still haven't pulled the trigger on batteries but I'm asking a few vendors if they could manufacture the jumpers too
Step-by-step guide for upgrading the Mitsubishi i-MiEV battery:

Prerequisites:​

• High-voltage safety knowledge and equipment
• Basic mechanical and electrical skills
• Arduino Due or CANFDuino for CAN spoofing found here
• Proper tools and workspace ( i'd love to expand on this )

Materials Needed:​

Battery Cells:

• 88x (or 80x for post-2012 iOn/C-Zero) NMC 93Ah cells with M8 terminals recommended
• Available from vendors on Alibaba like:
  • https://www.alibaba.com/product-detail/Starmax-High-Power-Catl-3-7V_1600752172388.html
  • https://www.alibaba.com/product-detail/Brand-New-CATL-Ternary-Lithium-Ion_1600494889608.html
  • https://www.xihobattery.com/products/catl-93ah-37v-nmc-prismatic-rechargeable-lithium-ion-battery
  • https://www.alibaba.com/product-detail/subject_1600869468591.html

Hardware:

• Cork/felt/corrogated plastic spacers for cell height adjustment (check this for details)
• Bus bars and jumper materials
  • machined (3.2mm thick 6061 aluminum without tapped holes from SendCutSend)
    • 76 x https://www.printables.com/model/1036239-l-shape-bus-bar-for-1233mm-ctc-battery-cell
    • 24 x https://www.printables.com/model/1036252-i-shape-bus-bar-for-1233mm-ctc-battery-cell-for-mi
  • diy (follow 5by8.net guide)
    • https://www.amazon.com/gp/product/B0BBDTQVYP/
• Arduino Due or CANFDuino with CAN shields
• Wiring and connectors for CAN bridge

Step-by-Step Process:​

Battery Pack Removal

• Follow detailed guide at: https://5by9.net/prune_batteries/pack_removal.html

Module Rebuilding

• Follow detailed guide at: https://5by9.net/prune_batteries/module_rebuild.html
• Key steps include:
  • Disassembling modules
  • Modifying plastic cell holders
  • Installing new cells with proper spacing
  • Making/installing bus bars and jumpers
  • Reconnecting CMU boards

CAN Bridge Setup

• Install Arduino Due or CANFDuino
• Download latest code from (github?)
• Connect to vehicle:
  • CAN0 to BMU pins 6 & 7
  • CAN1 to ECU
  • Power from switched 12V

Testing & Validation

• Check all connections and voltages
• Verify CAN communication
• Test drive and monitor performance

Important Notes:

• Always follow proper high voltage safety procedures
• Take time to properly balance cells before installation if there are any that have varying voltages connect in parallel for a few days.
• Document original wiring and connections
• The CAN bridge code is still being refined and improved
• Consider weather conditions as NMC cells are sensitive to charging/driving in freezing temperatures

 

[MickeyS70]

Nice summary, some clarifications:

- no need to reset the battery capacity to 45Ah (value is ‘overwritten’ by the CAN bridge)

- no CAN termination required as bridge ‘sits’ between nodes (unless your CAN shield provides galvanic isolation)

- some clones (post 2012 IOn/CZero) run on 80 cells only

- driving with a ‘frozen’ NMC battery pack isn’t recommended as high regen currents can damage the cells permanently

 

[program5628]

Thanks for the feedback. I've updated the instructions.

I'm looking for more details on tools required and the CAN Bridge setup.

If there is a repo I can link to for the code that would also be great.

 

[MickeyS70]

…the CAN Bridge setup.

Part 3 ‘Man in the middle’ (coming soon)
https://5by9.net/prune_batteries/mitm.html

If there is a repo I can link to for the code that would also be great.

File in post #197 seems to be the latest version so far…

 

[program5628]

If I make a github repo for this would you all want to contribute?
I can make it under an organization that you all could have control over.
The folder structure and version control might make this process easier to iterate on.
Up to you though because it's all your work.
You can even host your 9by5 instructions for free using github pages

 

[VoironIon]

If I make a github repo for this would you all want to contribute?
I can make it under an organization that you all could have control over.
The folder structure and version control might make this process easier to iterate on.
Up to you though because it's all your work.
You can even host your 9by5 instructions for free using github pages

With pleasure to help, clarify or contribute.

Sharing this knowledge for our IMiev, C0 or Ion is really useful.

Hope this helps

 

[martinwinlow]

If I make a github repo for this would you all want to contribute?
I can make it under an organization that you all could have control over.
The folder structure and version control might make this process easier to iterate on.
Up to you though because it's all your work.
You can even host your 9by5 instructions for free using github pages

Yes - within reason!

 

[program5628]

Ok I've made it and added a readme to the repo.

https://github.com/imiev-battery-upgrade/imiev-battery-upgrade

I imagine code and 3d print files and detailed instructions could be stored here.

If you want to be invited to the organization so you can make changes to the repo please dm me.

I've added a permissive license (MIT) for now but I'm happy to change that if it encourages contribution.

also made a nice little logo for it.

 

[toecheese]

I am _really_ happy to see the systematic documentation progress! Thank you so much to every contributor, however small!

 

[datom]

Ok I've made it and added a readme to the repo.

https://github.com/imiev-battery-upgrade/imiev-battery-upgrade

I imagine code and 3d print files and detailed instructions could be stored here.

If you want to be invited to the organization so you can make changes to the repo please dm me.

I've added a permissive license (MIT) for now but I'm happy to change that if it encourages contribution.

also made a nice little logo for it.

Great!
Small hint: First link to batteries on Ali does not work.

 

[Jiminy]

Need to find a seller with many reviews that has something to lose over a hit to reputation.

 

[program5628]

I feel like we need a bigger warning about freezing temps until we figure out a solution for that.

 

[program5628]

Better than pictures though is the parts themselves. Height differences are hard to discern from pictures alone. I received a full module and CMU boards (minus the cells) from an eBay seller in Canada. From this, I was able to figure out what was required to make spacer washers and bus bars for the unique cells Piev is currently working with. Also, I drew up and printed out a simple 3d printed "taco" for the bottom of his cells to center those cells in the stock plastic cell holders. All with his help, of course. He has ordered a small amount of metal parts to test fit and I sent him several tacos today to test as well. If everything fits then he will order the balance of metal parts.

View attachment 1354

Jim

would you be willing to contribute these files to the repo? https://github.com/imiev-battery-upgrade/imiev-battery-upgrade

 

[MickeyS70]

I feel like we need a bigger warning about freezing temps until we figure out a solution for that.

Regen is disabled at high SoC, therefore a quick fix (agreed, not pretty but effective) would be to set SoC to 100% while lowest reported cell temperature is below 5C?

Driving a bit (some testing required) should warm the cells sufficiently to use correct values again.


Unfortunately that trick won’t prevent the car charging below 0C, but then going around the block a few times (and/or turn on heater, AC, blower full blast) before you plug in should do work.

If you charge at home exclusively, modifying your EVSE to only activate your pilot signal above freezing might be the answer.

 

[program5628]

The dual cell bus bar above won't work with the stock plastic covers because the bus bar is mounted on top of the plastic cover. The cover has ridges or separators if you will that keep the original Yuasa cells from moving around, this feature prevents the cover from closing because these ridges hit the bus bar. In addition, the board will no longer connect to the CMU board because it is lower than the bus bar (even if you cut out the battery divider ridges. Looks like for this to work a new lid would need to be designed. The single CMU board connectors above look like they will work. Then just use stock bus bars to connect cells.

I'm compiling instructions here

I've added a recommendation of fabricating these bus bars and I'm wondering if that was premature given this comment.