Acceptable midpoint deviaton value?

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heinzie asked May 22, '21

Acceptable midpoint deviaton value?

Goodmorning

I have 2 x 2 victron agm 220 ah in series-parallel for 24 volt 440ah.

My midpoint deviation measured by smart shunt is around 0 to 0,3 % maximum.

This is up to 0,0 to 0,07 Volts difference.

When batteries are charging and in absorption stage the deviation is up to 0,7-0,8%

After charging is finished, deviation slowly goes back to 0 - 0,2

What is an acceptable value for this?

My alarm is setup around 2 percent by deviation (standard)

All is connected by busbars and equal cable lengths.

Setup is protected by battery ballancer.

Batteries are 2 weeks old and setup is as wel.

Can i expert higher or lower values?

Best regards and thanks in advance!

MPPT Controllers battery charging BMV Battery Monitor

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markus answered · May 24, 2021 at 08:29 AM

Hi Heinzie,

did you fully charge your batteries before you put them in a serial connection?

When you buy new batteries, they are most likely not on the exact same SOC, so it's always a good idea to charge them to 100% SOC BEFORE you use them in a serial string.

BR

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Answer 1 · 2021-05-24T15:02:52Z

heinzie answered · May 24, 2021 at 03:02 PM

Hallo Markus

Yes i did indeed

I notice the deviation is getting lessen now, around 0-0,1 percent but wh3n charging still up to 0,8 max

Thank you for your answer

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