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Capacity Detection After Battery Replacement

newbat
(@newbat)
New Member

Before the battery refresh, there were 4400mah batteries. Refurbished with 5200mah batteries. Reset was done and 5000 was entered as FCC value. The value obtained in the calibration and capacity test is 2850mah. What is the reason? It also charged the new batteries up to 4 volts from the charging tab. I was wondering why.

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Topic starter Posted : 22/07/2021 8:59 am
DjiBattWorkshop
(@djibattworkshop)
Member Moderator

- Paste screenshot from the first page with battery parameters

- Paste picture or model of genuine old cells

- Paste picture or model of new cells

 

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Posted : 22/07/2021 9:30 am
batFix
(@batfix)
Estimable Member

and don't forget a method of capturing SW pages:

ALT+PrtScrn -> c&p into MSPaint-> save as JPG-> attach the JPG to your message (Edit your message many times as many additional snapshots made)

Lets Make NLBA Great ! Together.

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Posted : 22/07/2021 9:44 am
newbat
(@newbat)
New Member

I re-discharged. The result is like this.

 diss
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Topic starter Posted : 22/07/2021 10:48 am
DjiBattWorkshop
(@djibattworkshop)
Member Moderator
Posted by: @djibattworkshop

- Paste screenshot from the first page with battery parameters

- Paste picture or model of genuine old cells

- Paste picture or model of new cells

?

 

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Posted : 22/07/2021 11:22 am
batFix
(@batfix)
Estimable Member

at least we can see cell3 voltage is 300 mV less than cells #1/#2... I would adjust it manually

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Posted : 22/07/2021 1:51 pm
batFix
(@batfix)
Estimable Member
Posted by: @djibattworkshop

?

also, please check/post internal resistance of the cells

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Posted : 22/07/2021 1:56 pm
batFix
(@batfix)
Estimable Member

Oh, this test found its capacity as 3800+ mAh

Lets Make NLBA Great ! Together.

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Posted : 22/07/2021 1:58 pm
torture
(@torture)
Member Moderator
Posted by: @batfix

at least we can see cell3 voltage is 300 mV less than cells #1/#2... I would adjust it manually

Such a deviation is normal since the cells are discharged below 3v. Ingnore SOC button utilizes the firmware safety discharge cut off voltage from fets. If there is such a deviation in the higher voltage range then it would be an issue. But we can't see that since the user doesn't post the needed screenshots. During normal operation the firmware will not allow cells discharge below 3.2-3.1v where the delta will become unstable. 

Example in the screeshot below. This is a battery that i worked on today and at 0% SOC the cells voltages are in the 3.26-3.3v range. 

If i continue the discharge with ignore SOC the imbalance will get bigger since no 2 cells are the same regarding IR. Even good quality ones.

If the chip is reprogrammed properly you don't even need to use the ignore SOC option, since all the calculations are done by the firmware.

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Posted : 22/07/2021 6:17 pm
batFix
(@batfix)
Estimable Member

TS plot does show Vcells right before and after cut off of discharge, plus cover relaxing period. All the time we still see the 300 mV difference, while during relax time the  internal resistance is not a factor here.

Follow Nicuror's posts we should see the deviation no more than 100 mV, perhaps plotting all three Vcell during charge time would reveal full individual cell's curves...

Lets Make NLBA Great ! Together.

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Posted : 23/07/2021 5:39 am
DjiBattWorkshop
(@djibattworkshop)
Member Moderator
Posted by: @newbat

It also charged the new batteries up to 4 volts from the charging tab. I was wondering why

to know why it would be useful to have same cells voltages plots at the end of charge, to check cells deviation there, may be one of the cells has higher impedance and so reach upper cut off voltage earlier so charging is stopped while another cells is not fully charged

 

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Posted : 23/07/2021 9:28 am
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