Hi,
I'm working on an automation project that's going to be powered by 12v batteries. This is going to have 48 of the largest odyssey batteries. These will be connected in parallel connected groups of 4 batteries, 16 groups total. The question is how to switch between groups. Do both + and - terminals need to be switched with relays, or can one side all be connected to a common buss, and only switch one leg?
I believe both legs needs to be switched, otherwise the charge will equalize between groups at a different potential (among other problems). But I'm getting some persistent arguments against me, and if we only switched one leg it would use half as many relays.
Any thoughts?

mk

Are you saying the load will be run with each parallel group of 4 batteries.  That is the load is only 12V?

If so then you only need to tie all the negatives together and to the load and then switch between your groups of batteries.

Weird setup you're planning.

Keith Cress
kcress - http://www.flaminsystems.com

Do not make the mistake of packing the batteries tightly against each other.  They need ventilation.

Mike Halloran
Pembroke Pines, FL, USA

What are you building? Those Odyssey batteries aren't all that big - maybe there's a better way of doing it.

There are almost certainly single cells with sufficient capacity to avoid having to parallel strings, which will simplify the scheme somewhat. Example manufacturers would be Hoppecke, SAFT, Alcad, Enersys to name a few.
  

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