Main Traction Battery Upgrade i-MiEV

[frank1]

a guy in Hungary is offering one on a facebook page

 

[frank1]

pic

 

[troy murphy]

Nice work guys
Battery pack looks awesome.

And as for the 'oooooooh don't do that's.....'
Imiev is discontinued
People keeping good cars on the road and keeping EVs on the road and still for there purpose is great by me.

 

[piev]

Finally I found the time to remove my pack and replace the CMU's. Powered up last night and connected the MUT3. No DTC's.

Yeah!

Next upgrade to the code I am going to work on is storing Remembered Ah so there will be less dependence on voltage checks. The code is already ported to a CANDuino board that has an SD card slot. (thanks to Mike Radtke) It also has room to add IC's so I may just add a EEPROM to the card.

 

[Joel_1885]

Thank you for your hard work in this unknown frontear

 

[behaluka]

Wow! I just read through this whole thread like a novel. Super interesting and impressive. Thanks everyone who is involved in this.
Before this forum I was looking for ready made upgraded battery packs and I stumbled over this Australian company who seems to have figured it out. Has anyone ever been in contact with them to ask how they solved the range limit?

 

[MickeyS70]

Wow! I just read through this whole thread like a novel. Super interesting and impressive. Thanks everyone who is involved in this.
Before this forum I was looking for ready made upgraded battery packs and I stumbled over this Australian company who seems to have figured it out. Has anyone ever been in contact with them to ask how they solved the range limit?

It’s actually the other way around, they created a commercial product using some information obtained on this and other forums.

Their ‘black box’ also contains a CAN bridge but has a few more functions (e.g. cruise control/one pedal driving)

 

[spchinch]

Hi everyone,

I am following this thread with A LOT of interest since I also got a quote to replace the i-miev battery in the state of Georgia of $13,000 plus labor.

A quick question: If I wanted to replace all the existing cells how many are there? or how much did you guys pay for replacing the battery from individual cells?
I am very handy and DIY, so putting an Arduino between the car and the battery is OK with me.

Thanks
Chris

 

[mradtke]

Hi Chris,

I paid $3,681 for 93 cells including tax and shipping in April. The car uses 88 cells. The rest were spares.

You need to consider the risk and safety precautions of dealing with high voltages. In addition, the pack rebuild is a lot of work. My son is working on some step by step instructions for the process. I will post a link here when he is satisfied with the content.

Our car is working just fine and I'm pleased with the result.

Mike - Phoenix, AZ

 

[mradtke]

Hello,

Please note that piev is the organizer of the traction battery upgrade effort and has consulted with many folks to get to this point. My son and I are now benefiting from piev's efforts. Our car's upgrade is performing as expected and we are very pleased.

My son is working on some documentation on "Pack Removal, Module Rebuild, and Man in the Middle." The first version of "Module Rebuild" is complete and may be found at:

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

I will post notice of the other sections when they are available.

Our thanks to piev and all the other people who have contributed.

Mike

 

[piev]

Thanks Mike. I look forward to reading it.

Just a note: I didn’t see a step removing the CMU screws from the batteries before removing plastic cover.

Oh, I see it. Step 9. I think there are 9 screws total. 5 on the main CMU and 4 on the daughter CMU.

Ok, I see it step 25. Very nice job Mike.

 

[greenfox]

This documentation is great! I am really considering now doing a battery replacement on my iMiev when the capacity drops too much. Thanks a lot!

 

[martinwinlow]

Hello,

Please note that piev is the organizer of the traction battery upgrade effort and has consulted with many folks to get to this point. My son and I are now benefiting from piev's efforts. Our car's upgrade is performing as expected and we are very pleased.

My son is working on some documentation on "Pack Removal, Module Rebuild, and Man in the Middle." The first version of "Module Rebuild" is complete and may be found at:

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

I will post notice of the other sections when they are available.

Our thanks to piev and all the other people who have contributed.

Mike

Hi,

Just read through your excellent document "Module Rebuild". Forgive me if I make one or 2 observations:

1/ Section 14 - 'Remove ~2mm on each side of the battery cage...'
This shows the full depth of the bottom section of the cage having plastic removed to accommodate the 4mm longer cells. Surely if you have to put 4 x 4mm = 16mm of spacer underneath the cells, you can avoid the need to remove that much plastic? What does that leave to actually remove? 10mm or less? Much less work and the unaltered plastic will mean what remains of the cage will be stronger ...

2/ Section 18: 'Fabricate jumpers to attach the CMU to the batteries'
Rather than reproduce the jumpers tediously from bus bars, would it not be much easier to make them from heavy (to allow heat movement so the CMU PCBs can still sense overheating cell terminals) gauge multi-strand copper wire with a suitably sized eye crimped onto each end? Or use a piece of maybe 0.5mm thick copper flat with suitably sized holes punched in each end and the centre section heatshrink-wrapped for insulation? Punching would be much quicker and neater than drilling... This would be added once the busbars are all connected - and on top of the webbing...? - almost entirely avoiding potential issues of breaking the PCB when tightening the cell terminal nuts. The PCB ends could be attached by first added a suitably long M4 screw and nut through the PCB hole and then the eye of the jumper attached with another nyloc nut. Not using the - quite thick original - jumpers might mean even less plastic removing in section 14.

Sorry if this sounds like ungrateful nit-picking...

Looking forward to the next ones. MW

 

[piev]

Hi,

Just read through your excellent document "Module Rebuild". Forgive me if I make one or 2 observations:

1/ Section 14 - 'Remove ~2mm on each side of the battery cage...'
This shows the full depth of the bottom section of the cage having plastic removed to accommodate the 4mm longer cells. Surely if you have to put 4 x 4mm = 16mm of spacer underneath the cells, you can avoid the need to remove that much plastic? What does that leave to actually remove? 10mm or less? Much less work and the unaltered plastic will mean what remains of the cage will be stronger ...

2/ Section 18: 'Fabricate jumpers to attach the CMU to the batteries'
Rather than reproduce the jumpers tediously from bus bars, would it not be much easier to make them from heavy (to allow heat movement so the CMU PCBs can still sense overheating cell terminals) gauge multi-strand copper wire with a suitably sized eye crimped onto each end? Or use a piece of maybe 0.5mm thick copper flat with suitably sized holes punched in each end and the centre section heatshrink-wrapped for insulation? Punching would be much quicker and neater than drilling... This would be added once the busbars are all connected - and on top of the webbing...? - almost entirely avoiding potential issues of breaking the PCB when tightening the cell terminal nuts. The PCB ends could be attached by first added a suitably long M4 screw and nut through the PCB hole and then the eye of the jumper attached with another nyloc nut. Not using the - quite thick original - jumpers might mean even less plastic removing in section 14.

Sorry if this sounds like ungrateful nit-picking...

Looking forward to the next ones. MW

You are welcome to experiment but I already tried that and this was the best method in my opinion. Mike may have another opinion but it looks as if he chose the same path.

 

[Negue]

Hello,

Please note that piev is the organizer of the traction battery upgrade effort and has consulted with many folks to get to this point. My son and I are now benefiting from piev's efforts. Our car's upgrade is performing as expected and we are very pleased.

My son is working on some documentation on "Pack Removal, Module Rebuild, and Man in the Middle." The first version of "Module Rebuild" is complete and may be found at:

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

I will post notice of the other sections when they are available.

Our thanks to piev and all the other people who have contributed.

Mike

Good job !

 

[MickeyS70]

2/ Section 18: 'Fabricate jumpers to attach the CMU to the batteries'

@phebbler ‘s ‘combined bus bar’ solution


https://myimiev.com/threads/cell-cross-referencing-pid-to-physical-cells.5645/

 

[mradtke]

Thank you for your reactions. I'll pass them along to my son Nicholas
who is the author of the document and co-worker in the upgrade process.

While there is a lot of detail, the document was not so much a recipe,
but a snapshot of what we did. If you follow it, it will work, but
there always will be room for improvement.

One change that we made that deviated from piev's experience is
ordering the M8 terminals to match the OEM cells instead of using
the default M6 terminals. This caused a lot of things to be a bit
different, such as the CMU jumpers as well as the spacers.

martinwinlow made some good points about the two most tedious and
difficult parts of the upgrade.

Section 14 - 'Remove ~2mm on each side of the battery cage...'

My son says:

"The batteries only need to be elevated 4mm, not 4 x 4mm = 16mm. So
while the bottom 4mm of the cage wouldn't need to be shaved, it's hard
to be that accurate when freehand shaving plastic."

"Not sure where the 16mm confusion came from -- maybe from the photo in
section 15C showing 12 spacers, but this is for all four cells in a
submodule, so three spacers per battery. If you can point me to the
source of confusion in the document, I'd be happy to update for
clarity. Thanks, Nicholas"


Section 18: 'Fabricate jumpers to attach the CMU to the batteries'

piev recognized the jumper challenge early on and tried a number of
designs. When it was our turn for the upgrade, my son and I re-visited
piev's work as well as brainstormed additional solutions. Stranded
copper wire, copper braid, and copper tape were considered, but nothing
matched the OEM design in performance as well as the thicker copper
jumpers similar to the ones that piev used. I looked at having the
jumpers fabricated, but it was not worth doing for just one car. We
chose to make them from re-purposed bus bars because that was the
lowest cost and easiest to do with our simple tools. Now that the
design has been proven in our car, it might be worth having a batch of
the jumpers machined if there is enough interest.

We also considered using @phebbler ‘s ‘combined bus bar’ solution, but
with I's and L's (some flipped) instead of I's and U's. The home
workshop fabrication was more difficult and spacers more challenging
since the module interconnect bus bars would be at a different height
than the inter-cell bus bars.

Mike