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4P16S LiFePO4 280AH Prismatic Cells by 3

DCK

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Jan 23, 2021
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Australia
I'm wanting to create three batteries with each battery consisting of 4P16S LiFePO4 280AH prismatic cells with its own 16 cell balancer. I'm then wanting to connect the three batteries in parallel. The three batteries will be built at the same time so the batteries will be the same age, stress etc. Is this possible and that simple?

If my calculations are correct a single 4P16S at 280AH, cells will be a 57kWh battery. With three battery banks of 4P16S it should be about 171kWh minus any system inefficiency losses.

Does that also mean that a 4P16S at 280AH prismatic cells; 1C = 1120?

Connecting three 4P16S batteries in parallel 1C = 3360?


At the moment the above is just what I’m wanting/thinking of doing and wanting to know if the batteries can be configured in such a manner. I’m thinking of taking my house in the suburbs off-grid. I estimate a 7 year break even.
 
Is this possible and that simple?
Possible, yes I think so.
Simple, maybe, possibly not as simple as you imagine.

I'm wanting to create three batteries with each battery consisting of 4P16S LiFePO4 280AH prismatic cells with its own 16 cell balancer. I'm then wanting to connect the three batteries in parallel. The three batteries will be built at the same time so the batteries will be the same age, stress etc.

With these large discount large capacity cells, staying balanced can be a struggle for some people, with just simple 1P packs, with 4P you will have to consider internal resistance as well. The cheap cells we are buying are not matched and are not true A grade cells so there is more variation in quality and characteristics.

You mention "each with its own 16 cell balancer", I just want to clarify that you will need a 16S BMS to properly protect each pack. You may need an active balancer per pack as well, this is an area I have limited knowledge.

Does that also mean that a 4P16S at 280AH prismatic cells; 1C = 1120?
Connecting three 4P16S batteries in parallel 1C = 3360?
I'm currently too lazy to do the math, but the gist of it is:
C-rate = Amps / Cell Amp-hours.
Combine cells in parallel and Amp-hours (for the pack) increase.
Combine packs in parallel and the Amp-hours (for the bank) increase.
 
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