System mode limit flip-flops battery between charge and discharge states when grid charge is enabled
Hi, has anybody else observed their SunSync flip-flop between charge and discharge states when you enable grid charge for a time slot in system mode?
E.g. my system mode has a limit set to 80% in the afternoon (15h00 to 18h00), and grid charge is enabled. I noticed it will keep discharging past 80% to 79% (battery supplies load), then recharge back up to 80% using grid, and then discharge again to 79%... and so the cycle repeats itself, putting the battery through 2 or 3kWh charge and discharge cycles all the time.
The solarman sampling rate is too low to show this well, but on a cloudy day with little solar, the problem still shows up and I also noticed it happens at night if I enable grid charge at night. E.g I exported device data and highlighted it.
If the above is not convincing, then a rough video I did showcases this issue in real time where the battery is, in very quick succession, switched between supplying load, and then getting charged by grid, and then back and forth.
This is not good and unexpected:
Puts unnecessary load on the battery.
Inefficient given charging a battery and discharging end-to-end into the battery is only ~90% efficient compared to just powering the load directly from the grid once the limit (e.g. 80%) is reached.
What I'd expect:
The inverter should block both discharge and charge from the grid once 80% is reached.
The inverter should still allow charge from PV, if PV is in excess of load (I had "Priority Load" enabled).
The inverter should probably only allow discharge once 82% or a bit more is reached and apply "Hysteresis." logic.
E.g. behave like a thermostat and avoid this flip-flop behaviour. See: https://en.wikipedia.org/wiki/Hysteresis#Control_systems
Related:
I've raised this question before, but it still remains largely unanswered and the video above shows it's not just natural battery discharge over time: https://www.sunsynk.org/forum/techical-support/why-does-the-battery-get-drained-beyond-limit-by-1
There's also sub-optimal or lacking Hysteresis control logic at 100% SoC to avoid small clipping charges and discharges: https://www.sunsynk.org/forum/techical-support/charge-start-stop-feature-request-for-better-lithium-longevity
Keith you are my only hope as I asked for my software to be upgraded also. I really only had bad luck so for with my setup, Flygen Consulting upgraded my software because my generator did not work on the inverter and from there on I only have bad luck as nothing worked like it use to work. I've taken the inverter back to factory settings but now my geaserwize system don't draw no power from the battery's anymore.
Please assist
Quintin