Today we had a short grid outage. Actual SOC was 20% and ESS minimum was set to15%. However ESS did not switch to island mode. Later I tried switching the grid off manually when battery was 90% and island mode worked well as expected.
ESS setting is optimized without battery life.
The ESS has been working well for about 5 months now without any problems but also without Grid outages.
Can somebody explain?
The ESS and the battery level of 20% SOC have nothing to do with ‘island mode’. The system would always attempt to continue supplying power via AC Out 1. If your SOC then drops too low, the system will naturally cut off the power supply. So it seems that one of the settings in VE Configure is incorrect… as your system ‘thinks’ the voltage is already too low… it could be, for example, that the sustain voltage is set too high. If your system falls below this level, it will try to charge the battery instead of discharging it… which, of course, isn’t possible because you’re not connected to the mains.
Thanks for your reply Steffen. I checked the VE configuration and all settings are according to battery manual. I tested net outage this morning with a low SOC (17%) and now the system worked as expected and I got Island mode. So very strange…
ESS also has dynamic cut off settings, something will be configured incorrectly or the instructions are wrong.
Not sure why you refer to it as “island mode”, essentially without grid the system will just continue inverting, unless you exceed the ratings or the various cutoff values, or, the BMS in the battery kicks into protect the battery from discharge.
You would need to carefully check all the relevant charts to see what voltages are doing, what ESS status codes are triggered, any alarms logged and ideally check the BMS logs.