I have an AC coupled Off grid system with Multi 48/5000/70-50 , 12x Enphase IQ7A micro’s and 14kWhr Lithium (LifePO4) battery storage. The micro’s and household are all connected to AC out 1, AC Out 2 is not used.
Following are main config settings relevant to the question below :
Absorption voltage 56.8V
Absorption time 1 hr
Float voltage 53.6V
PV inverter assistant
- freq (start reducing output power) = 50.25 Hz
- freq (min output power) = 52.0Hz
- freq (disconnect) = 53.0 Hz
It is a day with full sun (say 4kW solar PV production) , very limited loads i.e. 100-200W
When the battery is getting full and the voltage rises, the frequency slowly shifts towards 52.00 Hz, the Multi Absorption light comes on, no more power from the micro’s, but then …???
My question : What is supposed to happen over the next hour assuming sunshine & loads stay the same. Obviously, the voltage will slowly drop. Should the Multi Absorption light stay on, will it ever reach the Float state ? When will the frequency be shifted back to 50 Hz (what are the conditions) ?
I am seeing some behavior that I did not expect, but that could be my mis-expectation. Hence the question to clarify.
Thanks for your help