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EASun 5KW inverter draining battery in hybrid mode

Fixvid

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Apr 12, 2021
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Hi, i am testing EASun Igrid VEII 5.5kw inverter with 5KWh of li-ion storage.

The problem is that when inverter is in hybrid mode and it's supposed to suck energy from grid without getting the battery involved, it slowly discharges the battery overnight.



Sometimes there is a small reading of 1A on battery discharge current in hybrid mode. The voltage drops almost 2v after 15h.

The inverter seems to work ok in "battery mode" and discharges the battery accordingly, but i have a feeling that the battery is discharging faster than it should.

Did someone encounter any 'parasitic' discharge current on the inverter ?
 
The inverter uses the battery as power source if battery is available.

My BMS, In AC mode , reads 0.77A all night. This is how this inverter works. it seams that idle consumption will came from battery and maybe a part also from the grid.
 
The inverter uses the battery as power source if battery is available.

My BMS, In AC mode , reads 0.77A all night. This is how this inverter works. it seams that idle consumption will came from battery and maybe a part also from the grid.
Yes, I observe the same. According to the tracing of internal hardware, I found that priority to power inverter hardware itself is the following (from top to bottom):
- PV
- battery
- grid

In order to minimize power consumption of the whole system while there is no PV and my batteries are at the low SoC limit (I keep some reserve for the case of grid failure and also to prolong my LiFePO4 cycle life I usually not going under 15% Soc), my system switches the inverter to bypass mode, disables charging MOSFETs in BMSes and starts the external efficient switching power supply providing 52V to battery bus bars. In this case I was able to reduce the stand-by power consumption of the whole system to 20 Watt only. This stand-by consumption come fully from grid only. Batteries rest at defined 15% SoC limit. Once there is PV present again, the sequence is reverse: turn-off external power supply, enable charging MOSFETs in BMSes. After the system detects that there is enough PV power to keep charging of the batteries with sufficient charging power, it switches mode from bypass to battery mode again.
 
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