Adding new server rack lifepo4 battery to older server rack lifepo4.. drift issues

[Jamsolar876]

I've been using my older 24v Eg4 (GYLL) battery for about a year and a half now and decided to get a second. Of course the newer EG4 lifepower4 version doesn't communicate with the older GYLL. So I'm having issues with different rates of SOC on both the charge and discharge cycle.
I know that this is expected. However, what is the acceptable variance between the 2 in terms of SOC? I have them at the same voltage already but there's a 10-15% variance between the two SOCs...

 

[sunshine_eggo]

There's no one to establish an acceptable variance. All the "authorities" say:
Same brand, same model, same chemistry, same capacity, same age.

You're already violating at least two of the official rules: 1) same brand and 2) same age.

If you have connected them with best practices, all batteries are operating within their rated limits, and you aren't experiencing any disruptions due to any of the batteries cutting out at the top end or the bottom end, 10-15% sounds fantastic to me.

I would encourage regular charging to at least 3.45V/cell and dwelling there for a few hours per day to ensure the cells are top balanced.

 

[Jamsolar876]

There's no one to establish an acceptable variance. All the "authorities" say:
Same brand, same model, same chemistry, same capacity, same age.

You're already violating at least two of the official rules: 1) same brand and 2) same age.

If you have connected them with best practices, all batteries are operating within their rated limits, and you aren't experiencing any disruptions due to any of the batteries cutting out at the top end or the bottom end, 10-15% sounds fantastic to me.

I would encourage regular charging to at least 3.45V/cell and dwelling there for a few hours per day to ensure the cells are top balanced.

Ok , they get fully charged each day and only brought down to about 30% DOD each day.. Connected via bus bars and not daisy chained

 

[Zapper77]

Ok , they get fully charged each day and only brought down to about 30% DOD each day.. Connected via bus bars and not daisy chained

The length of time allowed to top balance is important...especially for new batteries.