bms help please

[Whiterabbit]

Hi,

I have an existing 48volt off grid installation using banks of sealed lead acid batteries. they are taking up heaps of room and i would like to change them to banks of recently acquired lipo 18650 batteries.

question is rather than use a 13s bms, 1 big array of batteries, can i use 4 x 3s bms's in series and put the chargers 55v across the lot?

Cheers
Ian

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[Hedges]

Only some BMS can handle being connected in series. The FETs would be subjected to a higher voltage when they turn off as part of a series connected set.
Whatever balancing is provided by the BMS will only occur within the cells of that BMS.
Seems to me if you can get one BMS for the entire series set of cells, that would be better.

Did you mean to write 13s? 3s? Both sound like unusual numbers.

Make sure what you build can handle the highest current the system will draw.
Look into a precharge resistor circuit; lithium can drive a much higher current surge when charging capacitors in an inverter.
If your location gets cold, make sure the BMS has low-temperature cutout.