62kw battery balancing

[Dave]

Hey, I got my second leaf, first one was a 2013 many years ago that I only had for a year, finally got another one, a 2020 sl plus
Had it about a month, still had leafspy pro from the first leaf.
Apparently the battery in this 2020 leaf had a few cells replaced under warranty 6 months ago before I owned it. I don't have any documentation for this.
Car gets great range, 95% soh, but a large chunk of cells are 70mv different.
Any ideas how to get this balanced?
I've read all the threads, left the car at 100% plugged in all night, no difference.
Thanks, Dave
Leafspy screenshot below....
https://ibb.co/NS4MTmS

[Learjet]

Had a module replaced and mine are set to balance at the lower SOC levels perfectly...my understanding is lower balance is more important to prevent early shutdown from a cell reaching the min. voltage before the rest of the pack...at a full charge my pack looks like this right now:




Click For Full-Size Image.


At lower levels:



Click For Full-Size Image.

[Dave]

Thanks, that makes sense, I haven't checked while it's been low. I'll try that!

[Learjet]

Thanks, that makes sense, I haven't checked while it's been low. I'll try that!

let us know...I'm curious to compare at lower levels

[Dave]

Will do. It will be a few days! I post an update.

[cwerdna]

You mean 62 kWh?

[Dave]

You mean 62 kWh?

Whatever....

[cwerdna]

You mean 62 kWh?

Whatever....

kW and kWh are totally different metrics. See viewtopic.php?p=450508#p450508.

https://www.mynissanleaf.com/viewtopic. ... 43#p564743 is a pointer to a cluster@$%$% that happens when someone doesn't know the difference. Back then, it was rumored the Model 3 would have an <60 kWh pack. And, Tesla was introducing per minute charging in places where they couldn't bill by kWh. They charged one price per minute for <60 kW charging and another one for >60 kW.

Just because a car has an <60 kWh pack doesn't mean it is limited to <60 kW charging but that guy reeler couldn't use the right units and get things straight, making discussion impossible.

Perhaps watching the video at https://electricrevs.com/2018/07/17/wat ... -to-55-kw/ would give you more context. Or maybe skip to 6:38 of https://insideevs.com/news/495913/nissa ... ing-curve/, watching power level (in kW) vs. energy dispensed in the upper right (kWh).

[Stanton]

Had a module replaced and mine are set to balance at the lower SOC levels perfectly...my understanding is lower balance is more important to prevent early shutdown from a cell reaching the min. voltage before the rest of the pack...at a full charge my pack looks like this right now:

Unfortunately, the replacement cells were installed at a lower value than the rest of the pack, so you can "cook" the rest of your pack all you want...but you won't ever get that new module to match. I have similar situation (although only ~80mV difference), but I installed the replacement cells at a higher value; it's been a very slow path to balancing for me.
Having said all that, you still look OK at the bottom end, which will keep you from an unexpected shutdown...but you will probably never be able to get "full capacity" from your pack. At least (in my case), I can live without those extra few miles.

[Dave]

So it makes sense, the cells that have been in the vehicle for 3 years have a lower capacity now than the new cells. If they were all balanced at low voltage the older cells will reach full voltage first. The balancing circuit will never keep up with the difference in capacity, so there will always be an imbalance somewhere....