Cell Balancing issue

[aneesh84]

I recently purchased a high milage 40 Kwh Nissan leaf. The battery had been repaired and all modules changed by the previous owner about 7 months ago. After driving I sometimes notice upto 31 mV cell difference although after a while the cells balance to 14-17 mV. The car otherwise drives well and has full range. Should it be a cause for concern?

https://i.ibb.co/sKn2Dj3/photo-2023-05-31-22-25-36.jpg[/img]

[aneesh84]

Charged up a bit over the night and now Cell Voltages look like this (14-20mV):



Seems to balance out sometimes, but after a drive reaches 30-35 mV

Am i paranoid or this is signs of some impending problem?

[LeftieBiker]

Welcome. The good news is that you're paranoid. A 31mv difference is nothing at all to worry about. When they get to 100mv or more, then you worry. Those ominous red lines on the histogram are just cells that are balancing, which is perfectly normal. Stop worrying and enjoy your new-to-you Leaf.

[aneesh84]

Thank you so much!!!! A big relief.

Its such a lovely car, and my first 2 weeks into the EV experience. Still learning a lot thanks to this forum and the amazing support I find here.

[aneesh84]

Any idea why leafspy does not show odo reading? Seems it has been disabled in the BMS!

[LeftieBiker]

When I had that issue it required an app update to fix it. I'm not sure if that's still the case, or if a menu item just has to be changed. Someone will help with that shortly, I'm sure.

[Stanton]

I suspect that section of lower cell voltages represent the replacement module(s). However, the delta at higher SOC is very reasonable (wish mine was that low). You should be good for the duration!

[goldbrick]

Any idea why leafspy does not show odo reading?

Was the car ready to drive when you took the LeafSpy screen shot?

I've found that different parameters disappear if the car is not 'ready', at least on 2017 and older Leaf's.

[aneesh84]

Any idea why leafspy does not show odo reading?

Was the car ready to drive when you took the LeafSpy screen shot?

I've found that different parameters disappear if the car is not 'ready', at least on 2017 and older Leaf's.

No, the odo readings have never shown up in my leafspy since i bought the car. Actually i was not able to download leafspy from playstore since i had the newest version of android. so i found an apk file somewhere on the net and installed it. maybe its an incompatible version.

Today the cells seem to have balanced out at an even lower SOC of 52% and i measured it after a drive. I believe all the modules were replaced maybe from different battery packs. Because this car is from 2018 and has done 220,000 kms and the modules were replaced in october 2022, and with the current SOH of 96.6 I dont think there is any original module, since the degradation would have been much more.