Balancing battery banks in series

[erik.calco]

It sounds simple, but is one area that is incomplete in our FAQ, though there is some good stuff there today. Let's discuss this in detail then try to summarize for this OP and our FAQ. Here are questions to kick it off:

1. How do you balance before putting in series?
2. How do you monitor a live bank?
3. How do you maintain it?
4. Impacts of chemistry over time (e.g., LiFePO4 vs LA).
5. Things that impact rate batteries go out of balance.
6. What if a "cell" (12V or 6V battery in bank) dies?
7. Over charging/over discharging risks and ways to manage?
8. How does resistance of batteries and cables play a role?
9. How do variations in battery age and capacity impact it if they are initially balanced?
10. Top vs bottom balancing?

Valid side-topics:

A. Parallel when it impacts in-series balancing.
B. Charge and discharge rates.
C. Measuring SoC.
D. Who has more beer in his home, @svetz or @Bob142 ?
E. Is @CheezWiz a bot?

Products
Victron Battery Balancer (Amazon $66)

References
Tapping A Battery For Different Voltages, Non-Standard Batteries (JeepHammer) - This helps to answer #2 and #3, how to monitor and maintain it.

GO!

I'll update this OP with links to answers.

 

[DIYportablegenerator]

24V victron battery balancer for batterys in series $94AUD

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[DIYportablegenerator]

heres how to connect balancer

 

[erik.calco]

Recommending products to balance batteries is great. I'll update the OP with a list of them. Yet, one goal in this thread is to build a FAQ to help people understand the theory so they can follow best practices in building their banks with a better understanding of balancing.

 

[erik.calco]

heres how to connect balancer

It is ironic because he is almost trying to talk you out of it by saying it almost never goes on.

It seems to be top balancing. I'm not sure that makes sense for LFPs, which can be in a very tight voltage range for most of their life cycle. I remember @Will Prowse had videos on the importance of bottom balancing, but that was for cells, not batteries in a live bank.

 

[erik.calco]

Poor man's battery balancing. ?

 

[Bob B]

Amazon reviews not real terrific for the Victron ..... https://www.amazon.com/Victron-BBA0...alancer&qid=1574731317&sr=8-3#customerReviews