LiFePO4 Battery Choice

[John]

Hello all, I am building a mobile PV generator and wanted to get 200ah @24v and I wanted to use Dacian's SBMS (which would be 8 cells in series). I found these online (https://www.electriccarpartscompany.com/200Ah-CALB-SE-Batteries). Are these a good choice? Seem to be 50% cheaper than a bank produced by Victron or Battleborn. With Battleborn at 12v, I'd be past the 8 cells that SBS0 can handle, so it seems like I'm limited in my choices to use with the SBS0. I've never built something like this before so any help is appreciated.

[Will OBrien]

CALB cells have a decent rep, but if you're willing to order from china, you can get a much better price - around $90 each for 280Ah cells.

[Dacian Todea]

John,

You can not use 12V type batteries (like Battleborn) with the SBMS0 and as Will mentioned there are even better priced batteries if you are willing to import from China

SBMS0 can support any number of Lithium cells as long as they are not more than 8s. So for example you can use 16 cells for a 24V system by having groups of 2 cells in parallel (same as having a single larger capacity cell) and then 8 of those in series for 24V or you can parallel 4 of them and then have 4 of those groups in series for a 12V system. 

[John]

Hi Will, that seems like a good deal. Do you know a reputable vendor? I'm leaning toward the cheaper cells because I'm new and if I make a mistake, it won't hit my wallet too hard. Have you had good experiences with the Chinese made cells? Thanks for helping.

[John]

Hi Dacian, thanks for the reply. If I wanted to start out with an 8S1P config at 24v (because I want the benefit of a higher voltage system) and can I then come back when I want more capacity and 8S2P the system a new set of 8 cells or is that not a good idea? Do all the cells need to be new for this to work? Is there a way to increase capacity down the road as a way to keep my price down now but still build a usable system now?

[Dacian Todea]

John,

Yes sure you can buy another 8 cells of same type later and then connect groups of two cells in parallel and have 8 of those groups in series for 24V.  You will not get more than 1 to 2% degradation in a year so it will make no difference if cell is new or you used it for a year or so and you can parallel one of the new cells with one of the old one to keep the groups of two cells equal as possible. 

[Will OBrien]

My order of cells just arrived, actually.

Info on that order is here: https://diysolarforum.com/threads/ordering-16x-280ah-cells-from-shenzhen-luyuan.13862/

I noted ordering, shipping and delivery times. I insisted on using my CC in case of issues over wires/etc.