The problem is only when the battery goes to 100%. (jk-bms CVL 55.2V (bulk) → 100% → CVL 53.6V (float))
In DESS mode the battery is then quickly discharged (P > 20kW) to the grid to get to 53.6V as quickly as possible. This only takes a few minutes (until 53.6V) and then DESS functions normally. (as per the settings)
If I switch off DESS it does go normally (CVL 55.2V → 100% → CVL 53.6V). The battery is then not quickly discharged to the grid to get to 53.6V as quickly as possible.
This is exacly the same problem.
Maybe I’m doing something wrong (I haven’t had my system up and running for very long) or it’s a limitation of the JK BMS, but I find it strange that in ESS operation everything just works as expected, but in DESS operation this effect occurs.
You would expect that if you lower the CVL below the battery voltage the charging will simply stop (this seems to happen without DESS = ok) and not if the CVL is lower than the battery voltage the battery will be discharged (max power) until the CVL is reached. (this apparently happens with DESS on).
Maybe I’m thinking too simple…
I have now turned off float mode in the bms. CVL should then always stay at 55.2V. I will watch it for a few days.