Voltage sag on 3KW EG4 inverter - lights flickering, UPS beeps

[Micah123456]

I have this issue where in the middle of the night the lights start flickering, ups starts beeping as the inverter starts seeing voltage sags. Running eg4 3kw inverter with one 5kwh egyll battery right now. See image, right around 4:33 i switched back to grid because my office UPS kept beeping sensing problem with the AC. The voltage sages down to 115, 114 volts. Note that for the 3kw inverter the load is not high, inverter 1 in both cases sags but is only seeing 600 watts on it. the battery would be at 55% or something at that point, so not low really. Wondering why its having trouble keeping the ac output steady. I don't think i have any big loads that its just not showing, ie big spikes. Any ideas or experience? Does a bigger battery bank help here to even out sags or is there a response time to loads the inverter has to catch up with?

 

[Brucey]

So there's two inverters on the single battery? What is the other one?

Was it working fine and this started recently? Check everything tight, no loose connections?

 

[DIYrich]

Are you off-grid (grid disconnected) or grid tied in self supply mode (you said switched back to gird)? If the latter, the inverter is following grid voltage, and is supposed to stay grid connected down to 87% of 120v, or 104.4v. The UPS is not bound by UL1741, and can have a tighter voltage range.

 

[Micah123456]

So there's two inverters on the single battery? What is the other one?

Was it working fine and this started recently? Check everything tight, no loose connections?

2 3kw inverters on the same battery yes, but the second isn't doing anything per the images. So its not like a large load is pulling down the system. Wondering if its an erratic draw that pulls it down for a split second but that isn't charted. Everything is tight as far as I know

 

[Micah123456]

Are you off-grid (grid disconnected) or grid tied in self supply mode (you said switched back to gird)? If the latter, the inverter is following grid voltage, and is supposed to stay grid connected down to 87% of 120v, or 104.4v. The UPS is not bound by UL1741, and can have a tighter voltage range.

Off grid but there is incoming grid power when the battery gets low. i have it on solar/battery/utility mode. So I don't believe its trying to follow grid voltage there. During the day it doesn't happen, I wonder if its the cushion of even a bit of solar power that prevents the ac frequency dipping . Could just be my single battery just sags sometimes I guess on particular loads causing this. But ya, seems to only happen at night when i'm sleeping.. i work all day long beside my ups and it rarely has issues

 

[DIYrich]

Off grid but there is incoming grid power when the battery gets low. i have it on solar/battery/utility mode. So I don't believe its trying to follow grid voltage there. During the day it doesn't happen, I wonder if its the cushion of even a bit of solar power that prevents the ac frequency dipping . Could just be my single battery just sags sometimes I guess on particular loads causing this. But ya, seems to only happen at night when i'm sleeping.. i work all day long beside my ups and it rarely has issues

If your system automatically switches to grid when battery is low or grid charges, then you are likely grid tied. If you manually connect and disconnect from grid, then you could be off-grid.

Try this: disconnect from grid. If voltage is rock stable, then you are probably following the grid. The EG4 3k has an "acceptable ac input voltage range" down to 85 or 90v depending upon setting 3.

 

[ojames600]

I am having the same issue with my eg4 6500, the low voltage is causing my UPS to trip, NEVER had this issue with my growatt, I measure the voltage from the eg4 and its only 119v. Can anyone change setting 10 on their EG4 inverter ? It will not let me change to 127v.