[Solved] 48v LL Battery cluster overloading charge amps modbus register

SomeJ · 2024-10-22T20:38:32Z

I have 36x 48v LL batteries clustered with closed loop communications to a Schneider Insight Facility device. There is a mix of v1, v2, and S versions in the cluster. Currently a v2 unit is acting as the cluster master and handles the communications with the Insight Facility device. What I am seeing is when the charge amps into the cluster goes above ~328amps the modbus register overloads and loops around to a negative number. I found some old modbus docs and the info there supports what I am seeing. How this is presenting its self to the Insight/Conext system is when the register rolls over to negative the system then thinks the battery cluster is now discharging instead of charging. While this is not a problem in general functionality, it does create issues with proper energy charge/discharge/use tracking/stats. An example of what I am seeing. Say the battery cluster is charging at 350amps. The cluster master then reports to Insight Facility that it is actually discharging at -305.35amps. How did we get to this number... 350amps - 327.67amps + -327.67amps = -305.35amps Layman terms.... (Actual charge amps) - (register max pos value) = (rolled over amps). (rolled over amps) + (register max neg value) = (amps displayed by master BMS) I suspect this same issue would happen if the combined discharge amps went below -327.67amps, the reported amp "draw" would wrap around into a pos number and the Insight Facility would then report the batteries as charging instead of discharging (I don't have enough inverters installed to be able to test that theory though) . I do not know what the current firmware version is that I am running on the batteries, but I do know they all have the same version on them. I added some LL-s units to the cluster earlier this year and had to downgrade their firmware to get them to talk properly with the rest of the cluster. I could try using a LL-s unit as the master, but the problem will still be there if the modbus register is still a 16bit signed integer. Same with upgrading firmware, I can give it a try, but unless an engineer verifies the modbus register size has been increased, then the issue will persist. So I guess the question is... Has anyone found a real way around this issue while maintaining full closed loop coms with the battery cluster and Insight Facility? And is EG4 aware of this issue? This probably was not as big of an issue with the old 16 battery limit, but now that they support up to 64 batteries in a cluster, logically it would take more amps to fully charge the cluster if it is being exercised daily. Thanks! J

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SomeJ

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November 19, 2025 7:47 pm

(@somej)

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And confirming my monitoring script is pulling in info properly without having to "compensate" for the register overflow.

Updating the thread to "solved".

Thanks again!

Jason

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[Solved] 48v LL Battery cluster overloading charge amps modbus register

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