2x24v versus 4x12v when building 48v system.

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gem asked Oct 27, '23

2x24v versus 4x12v when building 48v system.

I am about to have an electrical installer replace my existing 12v Victron system with a 48v system, which is needed for an Integrel high output alternator.

I have heard concerns about using four 12v batteries in series due to cell balancing problems.

So it has been recommended to me to use two 24v batteries in series instead.

However I notice that the Victron 12v330ah batteries have a higher energy density than the 24v batteries.

Is it recommended to use 4x12v batteries or 2x24v batteries to build a 48v system?

Is the use of battery balancers recommended for lithium batteries in series like this?

Lithium Battery 48v battery Battery Balancer

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Answer 1 · 2023-10-27T07:50:51Z

iammotorhomeless answered · Oct 27, 2023 at 07:50 AM

@gem My smaller system, I run 4 Epoch 12V 100Ah batteries as a 48V system. I was having the problem, that one of the cells in one of the batteries would hit a state of high voltage, and it's BMS would turn the charge Mosfet OFF.
once one battery stops charging they all stop charging.

I found an Eco-Worthy battery balancer on Amazons https://amzn.to/3MiBAzN for £50
I have only been running it a few days, but within an hour of wireing it in, the batteries finally went from bulk at zero amps to Absorbtion mode and then fully charged

the one problem I see witht the Eco-Worthy battery balancer is the low voltage disconnect. It runs all the time.
I have ordered a 0 to 60 volts low cut off switch, and some 10amp relays to manually/ physically disconnect the balancer when the voltage gets under 54 volts.

there maybe better solutions out there, but this is the only one I found

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gem commented · Oct 27, 2023 at 12:20 PM

Why don’t you just use the Victron battery balancer? They have a diagram in the manual for using it to balance a 48v bank.

Is the Victron battery balancer not for lithium batteries?

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iammotorhomeless gem commented · Oct 27, 2023 at 12:34 PM

@gem I thought the Victron battery balancer was only 24V.... so you need 3 of them for a 48V pack
at £60 each that's a lot more than I wanted to spend

edit, and reading the spec, the Victron battery balancer is only 0.7A
that's not a lot, when you are balancing 4 cells (12V) at a time

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