BMS for 3 parallel banks of LiFePo4

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graeme-w asked Jun 15, '21

BMS for 3 parallel banks of LiFePo4

We are replacing the existing lead acid bank on our barge for Winston LiFePo4 cells. Due to physical space limitation we've chosen to build 3 separate parallel banks of 16 x 300ah cells to create a 900ah 48V system.

The system is charged by a Quattro 15kVA and a MPPT RS 450/200 as shown in the diagram below with connectivity via a GX Colour Control.

We were hoping to use the REC BMS system, with an REC 16S unit (with shunt, precharger and contactor) on each bank, feeding into a Master unit which connects to our CCGX.

Will this work for parallel banks???? Despite several emails and attempts to phone REC we can't get an answer from them.

Or can anyone suggest another BMS that would be suitable for this configuration?

BMS

power-system-claire-version.jpg (110.9 KiB)

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Answer 1 · 2021-06-16T00:18:40Z

Mike Dorsett answered · Jun 16, 2021 at 12:18 AM

I think that the REC master BMS is designed for banks in series, not parallel; so whilst the individual slave units would probably work, the master would report 3 x terminal voltage, which would probably cause over voltage alarms in the CCGX. Main problem here is that the CAN bus protocols are not usually made public. I'm building my own Lithium batteries and BMS systems, and have written code on a PI for monitoring up to 32 banks in series or parallel or combination. However, the code does need to know the configuration. I see no registers in the rec master for this - hence my opinion.

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