Connecting LiPo in parallel to create large bank

boonxiong

Joined Oct 17, 2011
52
I have 2 3s(11.1v) batteries at 5ah each. Can I take apart these two batteries and double each cell so in total I will have 10ah (Assuming that they are very close in voltage)? So essentially.. 1 cell with have two cell in parallel?

Is this recommended and can you do this with lipos?

ian field

Joined Oct 27, 2012
6,536
I have 2 3s(11.1v) batteries at 5ah each. Can I take apart these two batteries and double each cell so in total I will have 10ah (Assuming that they are very close in voltage)? So essentially.. 1 cell with have two cell in parallel?

Is this recommended and can you do this with lipos?
Initially join them together with current limiting resistors to equalise them, then hard parallel them. I've seen up to 3S4P laptop packs.

boonxiong

Joined Oct 17, 2011
52
Why do we need a limiting resistors? I don't see people using it on Lithium Ion cells.

sumeryamaner

Joined May 29, 2017
114
I am connecting LiPo batteries in parallel using their balance connectors. That means I connect the main connectors in parallel using a Y harness and then connect the balance connectors too. This leads to a parallel connection in a cell basis. Before connecting I fully charge and balance the two batteries.
I have designed PCBs for this purpose. The two main connectors of the two batteries and the two balance connectors are connected to the appropriate connectors on the PCB and there is a single main lead and a single balance lead from the PCB to the charger. The two batteries are being fully united with this method.

ian field

Joined Oct 27, 2012
6,536
Why do we need a limiting resistors? I don't see people using it on Lithium Ion cells.
I'm guessing you didn't bother to read what I said.

boonxiong

Joined Oct 17, 2011
52
Hey ian, I was told that if you connect the cells in parallel, they will all naturally try to equalize each other out. Is this not true?

boonxiong

Joined Oct 17, 2011
52
This is what I would like to do. Can I do this without a current limiter? Just wondering because I see a lot of video on youtube where they don't use anything at all.

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ian field

Joined Oct 27, 2012
6,536
Hey ian, I was told that if you connect the cells in parallel, they will all naturally try to equalize each other out. Is this not true?
Just dumping 2 differently charged cells in parallel will result in a large equalisation current flowing that could damage 1 or both cells.

Join them will a current limiting resistor till they're balanced, then parallel properly and use them normally.