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
• Access to MUT3 diagnostic tool or equivalent (Lexia/Diagbox)
  • MUT3 can be found here
  • openport 2.0
  • purchase driver here
• Arduino Due or CANFDuino for CAN spoofing
• Proper tools and workspace

Materials Needed:​

Battery Cells:

• 88x 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
• 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
  • Add 120Ω termination resistor on BMU side
  • Power from switched 12V

Battery Reset

• Use MUT3 to reset battery capacity to 45Ah
• Clear any DTCs

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 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