battery capacity size setting

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Robert Slackware

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Apr 27, 2021, 11:25:08 PMApr 27
to electrodacus
What is the range for amp hours you can set for battery capacity?
The SBMS0 manual doesn't mention it.
I understand it is just to calculate the battery percentage display, but I am curious.
30kw may be enough for my project,  but can't hurt to make use of it as I grow to what I need without constantly needing to upgrade base components.  I'm building my vacuum table to start assembling panels now.

Dacian Todea

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Apr 28, 2021, 3:16:18 AMApr 28
to electrodacus
Robert,

The range is 0Ah to 9999Ah but above 3000Ah will just not be practical or economical.
I assume you will have a 24V 30kWh battery so around 1200A and absolutely no problem.

GLASHINC Developments

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May 9, 2021, 1:10:14 PM (9 days ago) May 9
to electrodacus
Hi Dacian,

If I can get 500Ah LiFePO cells would it still be impractical to build a battery with a capacity over 3,000Ah?

If so what is the reasoning for it being impractical?

Dacian Todea

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May 9, 2021, 1:46:31 PM (9 days ago) May 9
to electrodacus
The cell size has nothing to do with being impractical.
The SBMS0 can measure max 750A that means around 20kW for load or charge.
Then a 3000Ah x 26V = 78kWh so at max charge or discharge current posible limited by that 750A max current measurement you are at about 0.25C max charge and discharge rate.
So the reason is that with the max 20kW of charge current from max PV array you can install (you can install 30kW PV array in dual PV array setup but mac charge will still be limited to 20kW) then it will make no sense to have a larger battery than 3000Ah because it will not be useful to spend extra money on battery.

GLASHINC Developments

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May 9, 2021, 5:34:28 PM (9 days ago) May 9
to electrodacus
Thank you Dacian.  I had missed the 750A limit.

Understand perfectly!

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