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damien-walker avatar image
damien-walker asked

Midpoint voltage management - intervene or trust the system?

Hi all


My installation includes a battery bank consisting of 6 x 12V lead acid batteries connected in 24V series-parallel with a SmartShunt and Victron battery balancer.


Each morning the midpoint variation typically jumps to around 1% before quickly stabilizing. It has recently been climbing closer to 2%, a couple of times over 2%, before settling back to normal.


The battery balancer is clearly doing its job so my question is this: providing the midpoint voltage doesn't climb far over 2% (but how far?) and providing the balancer continues to quickly stabilise the voltage, do I need to be concerned about the recent rises in midpoint voltage or can I leave the system to do its thing, knowing the balancer will keep the batteries safe?

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kevgermany avatar image
kevgermany answered ·

Check your wiring. Is the positive on one bank and the negative on the second?

Some discrepancy can be expected, but this, to my mind, is too high.

You might have batteries on the way out. I know @Alexandra regularly swaps her batteries around to even out loads. Well worth considering. If you label the batteries and check individual voltages you may get a better idea of each battery's condition.

Also check absorption voltage/time.

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Alexandra avatar image Alexandra ♦ commented ·

@Damien Walker

Internal resistance changes in individual batteries in a battery bank. It is worth rotating batteries. Sometimes using a 12v charger and taking it out the bank and giving it a good individual charge

Current sharing is a thing in banks like yours. (So wiring set up is pretty important). The balancer is doing its job though. But consider every 3 to 6 minths depending in cycling some rotation.

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