Re the ESS manual: "If the target state of charge is reached, and it is still within the period of time set, the battery will stop charging but will not discharge (unless there is grid outage)."
This works fine for me if SOC target isn't set, i.e. if I'm charging to 100%. I have Economy 7, the Pylontech batteries charge up after a couple of hours or so, then go into 'Idle' state. However, if I set an SOC target to say 85% (given I'm now getting usable PV) the batteries reach the SOC but don't go into Idle. The fluctuate between idle and discharge. In a stack of 4 Pylon batteries, it varies which battery goes Idle and which discharges. Sometimes all 4 are discharging. End result is that by the end of the E7 cheap rate period the batteries are at around 83%, not the target 85%.
Eventually, if I can find reliable PV yield forecasting data, I'll be controlling charge/discharge/SOC via modbus but wondered if what I'm seeing is 'normal'? Pic below of 'scheduled charge'/no grid outage/discharging.