LiFePo4 4batteries in parallel

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mswoboda asked Dec 17, '22

LiFePo4 4batteries in parallel

Hi,

I want to use LifePo4 batteries in parallel.
I will use a Chinese model which are able to "talk" to VE.Can bus. I think they are using the Pyontech protocol.

Suppose I will use 5 batteries with 48V and 230Ah and the BMS can handle 200A charge and discharge.
So the question is: What is the maximum Amperage I can charge and discharge with 5 batteries in parallel?

Kirchhoffs law says that the current is reduced in a parallel circuit:
As all batteries will be parallel, theoretical I could use 5x200A = 1000A, but in reality its too much, isn't it?

One company gave me a formula:
n...number of batteries
n x 200A / 2 = Max A

This would be 5 x 200 / 2 = 500A

What is the experience of the community?

I am happy with any answer!

Lithium Battery BMS charge current limit 48v battery

3

2 |3000

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Alexandra ♦ commented · Dec 17, 2022 at 06:18 PM

@mswoboda

Check you can run 5 in parallel. Alot of batteries can't.

But in theory you have "enough" amperage to run a 45kVa load depending on your current share in the set up.

How are you wiring it up? To a bus bar individually or looping them?

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mswoboda Alexandra ♦ commented · Dec 18, 2022 at 01:04 AM

I will use Lynx.

You can use 15 batteries in parallel, thats what the producer confirmed.
The question is: What is the maximum of Ampere I can charge and discharge e.g. with 5 batteries (each battery has a BMS up to 200A).
The load of kW is a different thing. This has also to do with the inverters. But thats a different topic.

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mswoboda Alexandra ♦ commented · Dec 18, 2022 at 01:39 AM

...or did you mean busbars between the batteries?

At the moment I plan to connect each battery with cables.

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Answer 1 · 2022-12-18T04:28:08Z

mswoboda answered · Dec 18, 2022 at 04:28 AM

I think in the meanwhile I know the answer. Its better to build a busbar. Otherwise the batteries outside will be more used as the inner ones.

2 |3000

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