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bazil asked

Help needed with battery management system (4 x 200Ah lead acid in parallel)

I would like to expand my current 2 x 12 V / 200Ah lead acid batteries (in parallel) to a total of 4 batteries (also 12 V / 200 Ah).

If I understand correctly, given the different properties of each battery, the internal resistance of each battery means that one battery may 'hog' the input charge.

I believe I need an 'intelligent' battery management solution to address this; could anyone please point my in the correct direction regarding a suitable device and instructions?

Charging is undertaken by Multiplus 12/1600/70 and MPPT 20A

Best regards

battery charginglead-acid
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2 Answers
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snoobler answered ·

Read here for information on various proper ways to wire batteries in parallel https://www.victronenergy.com/upload/documents/The_Wiring_Unlimited_book/43562-Wiring_Unlimited-pdf-en.pdf


Since the batteries are in parallel, they will always be at the same voltage, so there's no device that can manage them individually, i.e., if you connect to battery 1 that's in parallel with battery 2, it is reading the voltage of both battery 1 and battery 2.


Wire your batteries consistent with the methods shown. Use a clamp DC ammeter to verify how the batteries are sharing current under high loads and high charge rates.


If you use the first and simplest methods where you place the main (-) on battery one and the main (+) on battery four, batteries 1 and 4 will tend to experience higher current on the order of 5-10%. The new batteries should be placed in positions 1 and 4 since they are better suited to higher currents with the old batteries in the 2nd and 3rd position.

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bazil answered ·

Really appreciate this!
Thank you so much for your help

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