Trying to understand charge rates
Posted: Sat Apr 18, 2026 9:22 pm
Hi. We have just added an EQ4300w battery stack (12.96kWh) to our existing solar panels, connected through a Fox ESS AC1-5.0-E-G2-WL inverter.
I am using the nathanmarlor modbus integration in Home Assistant. This produces lots of entities, mostly self-explanatory. I have found a really helpful explanation in an old thread on here about the various temperatures that are reported.
However I could do with some help understanding the various charge rates: searching has turned up hints in various threads but not a clear reference. (I see some threads in the AC forum but very out of date).
BMS Charge Rate
- I assume that is the key rate at which the battery gets charged? Ours varies in big steps between 23A, 33A and 50A. What governs this I think is a mix of temp and SOC? I have seen spreadsheets of temperature vs charging current online from different dates, but they do not seem to relate directly to the behaviour we see. Any up to date guidance?
And what are (and does it matter):
Battery Current
Inverter Battery Current
R Current
Max Charge/Discharge Current(s) - ours are both set at 40A.
Thanks.
I am using the nathanmarlor modbus integration in Home Assistant. This produces lots of entities, mostly self-explanatory. I have found a really helpful explanation in an old thread on here about the various temperatures that are reported.
However I could do with some help understanding the various charge rates: searching has turned up hints in various threads but not a clear reference. (I see some threads in the AC forum but very out of date).
BMS Charge Rate
- I assume that is the key rate at which the battery gets charged? Ours varies in big steps between 23A, 33A and 50A. What governs this I think is a mix of temp and SOC? I have seen spreadsheets of temperature vs charging current online from different dates, but they do not seem to relate directly to the behaviour we see. Any up to date guidance?
And what are (and does it matter):
Battery Current
Inverter Battery Current
R Current
Max Charge/Discharge Current(s) - ours are both set at 40A.
Thanks.