AC500 takes (a bit of power) from grid even when turned off

Why does the AC500 sometimes take some power from grid even when Charge From Grid is turned off?

Hi @digait, Could you please confirm if the serial number of your AC500 is AC5002308000976556?

We have already pushed the new IOT firmware version v9041.10 for you, and we hope it will help.

I have the same problem.
Can you give me an update too?


Yes, my serial number - and latest IOT installed.

Sorry, but the inverter shows the same behaviour:
from time to time it loads a bit from the grid.

I noticed a few days ago mine too will momentarily draw Grid power when I turn on a heavy load, like my Microwave. It lasts maybe 5 seconds then goes back to Zero. Is this some kind of power use surge protection?

Interesting to know if there is such “power use surge protection”
because I also have some heavy consumers (about 2200 Watt)
and now I have plugged the AC cable from the grid.

Hi @digait, We believe this issue might be related to your UPS settings. Could you show us the interface you have set up?

Additionally, is it possible that the solar charging is not performing well, resulting in occasional loss of input and switching to grid charging?

These are the settings:

I think it has nothing to do with solar charging because there is AC charging even when there is night time:

The Bluetti team does not know why it happens?

Today I have seen that - though charging from grid was turned off -
for a moment (a second, or less) energy was taken from grid when a
consumer switched on:

There was

  • charging from solar panel (ca. 600 W)
  • a continuous consumer (hotplate ca. 1100 W)
  • a second continous consumer (freezer ca. 70 W)
    and a
  • little oven (ca. 1500 W) regularly turning on (and off, controlled by a thermometer)
    which caused a short input of ca. 230 W from grid.

Then I turned off the hotplate and now, when the oven turned on the input from grid was ca. 320 W.

It also pulls some Grid Power for a heavy load surge, such as when I turn on an air conditioner or microwave.

I’ve since unplugged it from the wall outlet because the output voltage is higher than the Grid voltage, especially in the Summer.

Hi @digait, We would like to know how you have disabled grid charging.
Did you do it through the UPS settings or the smart switch?
If you want to completely disable grid charging, the best option is to unplug the charging cable.
@St8kout’s answer is very helpful.

Hi @digait, We have consulted with our engineers regarding this matter. Even if the grid charging function is turned off, the AC500 may still briefly draw power from the grid when the load starts up. This is typically done to ensure the load starts smoothly and to prevent system instability due to excessive instantaneous power draw.