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Re: Replacement Battery with low cell Voltages

Posted: Mon Jan 09, 2017 12:28 pm
by arnis
It just seems that way. From 3V to 2.6V there is hardly a percent of capacity difference.
It translates to 0,01V difference at top end. Aka same capacity difference (a percent).

If any cellpair drops below 2.5V it kills the contactor. Even during acceleration. This is why
power bubbles disappear a mile before dead.

Re: Replacement Battery with low cell Voltages

Posted: Fri Jan 20, 2017 2:58 pm
by Marktm
Update - new battery has about 1200 miles on it and about 1-1/2 months. AH has dropped from 66.14 to 63. SOH dropped to 98%. Temp bars always mid-range, one QC, one "VLBW". At this rate, a I'll be back to my old batteries final reading of 43 AH in a little over a year.

I'd guess that as the pack balances better this will level off - but no sign yet.

Re: Replacement Battery with low cell Voltages

Posted: Thu Apr 20, 2017 5:45 pm
by Cor
Marktm wrote:Update - new battery has about 1200 miles on it and about 1-1/2 months. AH has dropped from 66.14 to 63. SOH dropped to 98%. Temp bars always mid-range, one QC, one "VLBW". At this rate, a I'll be back to my old batteries final reading of 43 AH in a little over a year.
I'd guess that as the pack balances better this will level off - but no sign yet.

Mark,
Please note that the fabled 66.14Ah is just a magic number, not actual capacity of the battery, but rather something that gets programmed into the BMS as a starting point. Initial change can be fast, due to BMS learning the *real* capacity of the pack. Once that is found, degradation follows its normal course.
Cor.

Re: Replacement Battery with low cell Voltages

Posted: Thu Apr 20, 2017 8:35 pm
by Marktm
Yes, I've found that the AHrs and SOH has varied quite a bit since the new battery in place - went through a period of rapid drops and then would recover. I have a section of (10) cells that are about consistently 20 mv (after a full charge) below all the other cells. The lowest mv range I've seen is 24. I don't know if that is common, but makes me wonder if the original cells were not well selected or it just takes more time to "balance" properly.

Re: Replacement Battery with low cell Voltages

Posted: Thu Apr 20, 2017 10:02 pm
by GerryAZ
Try changing the shunt order to 8421 in Leaf Spy settings and see if it then shows the higher cells being shunted instead of the lower ones. I had 160 mV difference deep into VLBW last night and 16 mV difference at full charge this morning on my 2015 so I'm not too concerned to see 112 mV difference in your first screenshot. I suggest you drive and charge as you need and see if the cells balance better after more cycles.

Re: Replacement Battery with low cell Voltages

Posted: Fri Apr 21, 2017 1:19 am
by SageBrush
@marktm,
You may find a thread from a few months ago informative that described a manufacturing defect in a new 2017 car. A couple cells were defective from the get go and IIRC voltage deltas over 200 mv easily logged. I don't think a MIL was ever set.

I agree with an earlier poster that Nissan is not going to care. You can keep logging for your own interest and ours, or just drive the car and hope for the best. My fingers are crossed that this sorts itself out, and that it is not a harbinger of what to expect in future replacement packs but Nissan's history leaves me antsy on your behalf.

Re: Replacement Battery with low cell Voltages

Posted: Sat May 06, 2017 11:16 am
by Marktm
Update on 11/3/16 battery replacement:
5/3/17:
64.76 ahrs
100.00 SOH
97.15 HX
386.07 VDC
222 GIDS
32539 miles (~2800 miles on new battery)

Appears things have settled down and "Lizard" is alive and well.