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kuban-invertor avatar image
kuban-invertor asked

Battery balancer for Gel Batteries.

Hi experts! I need your advice. I have lead-acid batteries. Type GEL.

Amount - 72pcs. And three Quattro inverters (10kW).

How much do I need a Battary Balancer to equalize the charge?

According to which scheme is it optimal to connect?

It will be an ESS system with Fronius Symo. Thanks!

Battery Balancer
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kuban-invertor avatar image kuban-invertor commented ·


forgot to add - 48 volt system

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3 Answers
porcini avatar image
porcini answered ·

Holy cow! ... 72 Pcs of single 12V(?) gel batteries in a 48V system? I promise that won't last that long, no matter if balancers are used or not.

Looks like a very big system to me with 3 10kVA Quattros in it. Who told you to use that many small batteries? You better should use 2V cells for a system that big.

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kuban-invertor avatar image kuban-invertor commented ·
Initially, the project was supposed to be 20 batteries. But in the end it turned oгt that way. Now my task is to make the system as balanced as possible. Do you think this is impossible?)
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Matthias Lange - DE avatar image Matthias Lange - DE ♦ kuban-invertor commented ·

Take a look at the datasheet.

https://www.victronenergy.com/upload/documents/Datasheet-Battery-Balancer-EN.pdf

For a 48V system you need at least 3 balancer. But with such a big system you will need a "few" more.

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kuban-invertor avatar image
kuban-invertor answered ·


Thanks for the help! very useful information! What is the best way to connect the midpoints of all batteries?

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porcini avatar image porcini commented ·

You can't. Each series has its own midpoint.

I would really recommend you to sell all these batteries and go for 2V cells instead .. otherwise you won't get happy.

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kuban-invertor avatar image kuban-invertor porcini commented ·
Why do you think that you do not need to combine the midpoints of all batteries? This is not logical (in my opinion). After all, then you get something like islands. And each island will have its own tension. I think it can be balanced. Need more info.
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porcini answered ·

Due to tolerances every battery has its own values, so litte deviations are quite normal (apart from cell drifts). When you force a battery to a voltage level which is different from its natural one it is harmful in the long run. That is why I avoid using many batterys in parallel and don't recommend using balancers in a lead battery system. I also don't recommend 12V blocks for a 48V system. 2V cells are the way to go. They are more similar (less tolerances) and balancing is done by a careful overcharge. Cell drifts are more rare. That is why I recommend for the 3rd time to go for 2V cells as long as you won't want to buy new batteries after 5 years. But as I see you want to have your own experience ...

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kuban-invertor avatar image kuban-invertor commented ·
thanks for the info. 5 years is a sufficient period for the system. What do you think about the fuses for each string. Photo as an attachment. Connect a battery balancer with midpoints. How will it work?
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