Main Traction Battery Upgrade i-MiEV

[piev]

Good point, we know from commercial solutions that they are able to limit the CHAdeMon power after NMC cell upgrades. I gather that they’re applying an official Mitsu ‘update’, does anyone have further details?

Pretty sure you can do this with the CAN bridge. I know the OBDZero app can monitor the charge profile so the data has to be on the bus. Does it go from the battery to the ECU or through the BMS. Pretty sure it goes through the BMS in which case you could change the current being requested. I do know that the charging has a different current sensor than the pack but I don't know details. I believe that Kiev figured this out. I could be wrong. Maybe I'll spend some time snooping around now that I have a MiEV again.

 

[hat]

Good point, we know from commercial solutions that they are able to limit the CHAdeMon power after NMC cell upgrades. I gather that they’re applying an official Mitsu ‘update’, does anyone have further details?

Thank you.
It is possible that a software "update" could limit the upper limit of the fast charging current. However, this forum has not yet discussed "updates."

 

[hat]

Pretty sure you can do this with the CAN bridge. I know the OBDZero app can monitor the charge profile so the data has to be on the bus. Does it go from the battery to the ECU or through the BMS. Pretty sure it goes through the BMS in which case you could change the current being requested. I do know that the charging has a different current sensor than the pack but I don't know details. I believe that Kiev figured this out. I could be wrong. Maybe I'll spend some time snooping around now that I have a MiEV again.

This is a way to convert current data using a CAN bridge without "updating" the software.

 

[MickeyS70]

Pretty sure you can do this with the CAN bridge. I know the OBDZero app can monitor the charge profile so the data has to be on the bus. Does it go from the battery to the ECU or through the BMS. Pretty sure it goes through the BMS in which case you could change the current being requested. I do know that the charging has a different current sensor than the pack but I don't know details. I believe that Kiev figured this out. I could be wrong. Maybe I'll spend some time snooping around now that I have a MiEV again.

Yes, I hope so. While the CAN communication between the EV-ECU and CHAdeMon EVSE is separate and charging limits are probably set on that level, the BMU seems ultimately in control as it’s monitoring the HV battery.

I gather it sends a ‘target current request’ to the EV-ECU which is then forwarded to the EVSE. If that’s the case, it should be easy enough to limit this value with a bridge if we only knew it’s PID?

@kiev has recently added some interesting info:
https://myimiev.com/threads/whats-all-this-chademo-can-buss-stuff-anyway.5727/

 

[hat]

Thank you.
I understand the information about CAN communication.
I can adjust the maximum current value to the NMC.

 

[Negue]

I know at Leaf that Can bridge can limit charging (30+kwh)

 

[MickeyS70]

I know at Leaf that Can bridge can limit charging (30+kwh)

Yes, that is where I found the information about the ‘target current request’, assuming this to be similar on a triplet…

 

[iso14000]

Hello,

I came across this cell which looks a lot like a LEV50, including the CMU tabs:

https://www.alibaba.com/product-detail/OEM-ODM-Customized-Pack-New-Prismatic_1601105521478.html?fromPlat=buyer_ops&mt=mail&crm_mtn_tracelog_log_id=82694070612&crm_mtn_tracelog_task_id=push-task_66592&crm_mtn_tracelog_template=2000114762&crm_mtn_tracelog_creative_id=33598&as_token=4HMr+liSzzceD5KyMXhVVAs7dvfs7dvf&[email protected]&[email protected]

I didn't immediately see dimensions so it may not be a match. For those who would just like to rebuild their pack without increasing capacity, this could be a good choice. The price seems right. I'll leave it up to others to research this cell, since I am pleased with my upgrade.

Mike

HI

I've just make an inquiry to them, especially about dimensions, they fit a LEV40 not a LEV50 .
the LEV40 is finer and heigher than LEV50.
nothing to do with that....

I'm joining in the lev50 to CATL93 swap ... gonna order cells to start to rebuilt a spare module of 8 , don't know really how to set the "8mm option", but I dig ofr it.
happy new years for all....

 

[Jonny]

I apologize for the possibly stupid question.
Can I replace only some of the batteries with CATL93, e.g. 20 out of 88?
Or it is impossible to mix batteries...

 

[MickeyS70]

I apologize for the possibly stupid question.
Can I replace only some of the batteries with CATL93, e.g. 20 out of 88?
Or it is impossible to mix batteries...

It's not impossible to mix battery chemistry, but it's not recommended. The packs capacity and performance will always be defined by the weakest cell, therefore replacing 20 bad LEV50 cells with CATL93 is unlikely going to make a difference in the long run.

Picking the 20 worst cells isn't straight forward either, most likely you will miss a few and these will need to be replaced shortly afterwards.

Balancing a mixed capacity cell HV pack is (almost) impossible.

Last but not least, CHAdeMon (rapid DC charging) could exceed the maximum current rating of CATL93 cells.

 

[Jonny]

Thanks for the answer
There are no problems with charging, I use 10 amps of AC in 100% of cases
The question is more about investments, to replace dead cells with brand new ones of the same type, or to do a gradual upgrade

 

[MickeyS70]

The question is more about investments, to replace dead cells with brand new ones of the same type, or to do a gradual upgrade

It's highly unlikely that you will find 88 new LEV50N cells.

Not sure if you have ever removed the HV battery on triplet, without a car lift, this can be a very time consuming operation.

Worst case, you could end up with a mixed capacity pack if your peace meal style approach is taking a long time.

 

[Wenny Yuan]

Except CATL93,what other batteries are suitable for Mitsubishi imiev & outlander?
We have solution without changing the original bracket!

 

[hat]

Except CATL93,what other batteries are suitable for Mitsubishi imiev & outlander?
We have solution without changing the original bracket!

This is an interesting product. It would be nice if you could sell not only battery cells, but also bus bars and spacers to fill the gaps.

 

[Wenny Yuan]

This is an interesting product. It would be nice if you could sell not only battery cells, but also bus bars and spacers to fill the gaps.

Haha, we customized studs and provide busbars ,spacer also available ：）

 

[MickeyS70]

Haha, we customized studs and provide busbars ,spacer also available ：）

Doesn't look like these cells will fit across the CMU boards I'm afraid...

LEV50: 171mm x 44mm x 98mm
CATL93: 172mm x 42mm x 90mm
SVOLT90: 148 mm x 39mm x 102mm (short and high)

[edit] actually the CMUs are only 65mm wide, but the excess height is going to be a (mission impossible??) challenge..

 

[stoatwblr]

I apologize for the possibly stupid question.
Can I replace only some of the batteries with CATL93, e.g. 20 out of 88?
Or it is impossible to mix batteries...

Given the differing battery chemistry (and therefore discharge voltage curve), it would be a spectacularly bad idea to mix cell types

 

[stoatwblr]

It's worth noting that both the CATL and SVOLT cells are limited to 1C charge/3C discharge whilst the original LEV50s are 2.5C charge/6C discharge

That puts the allowable currents at _about_ the same for discharge, but charging will need to be limited a little (not that I've ever seen Chademo exceed 65A even with 150kW chargers, so the existing programmed limits may be fine)

One of the things that I've been wondering about would be shoehorning LiFePO4 cells into the packs. I know that would require serious reprogramming and potentially mean a 20% reduction in peak power, however they tend to have vastly greater tolerance of charge/discharge currents as long as the low-end thermal requirements are met (ie: no charging below freezing and a pack heater probably needed) and they have longer cycle lifetimes than NMC

There's a bigger problem eyeing most of us in cold(ish) climates where road salt is used: Chassis corrosion. These are repurposed JDM cars and have fairly poor rust protection. It may not be worthwhile investing several thousand dollars in a new battery pack if the car ends up failing annual safety inspections due to rotted-out suspension mounts

What are people finding under the skirts when the battery pack is dropped out?