AC300 Customized UPS mode setting fails to cut off power output at SOC low setting

Although it should, according to the manual. I set the setting at 95% Battery SOC High and at 5% Battery SOC Low. The former one works well - the unit stops charging once it reaches 95% SOC. It fails to turn off AC output on its own though - I had to switch it off manually at 2% SOC tonight. What am I doing wrong? Thanks

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It’s probably a bug. Other people have the same problem.

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@Oleksiy When the high value of SOC is reached, the output will not be cut off. But the machine will turn off the utility input and the remaining power can only be filled by PV charging.

@BLUETTI Yes, and this is very good - I’m interested in AC output to be on once the SOC high value is reached, this part works well. I was referring to the operation of SOC low setting instead - it’s not enforced properly. It’s crucial to protect the AC300 from draining the battery and down to the level when the unit is unable to load and charge it anymore. I don’t have any way to charge my B300 directly yet.

@TheQuickFox Thank you, it’s good to know I’m not alone. It’s not good that the feature won’t work though. Hope there are plans to address this in the next firmware release.

I have a AC300+B300 and have the same problem with the low SOC. It is not stable at the low end. So I set my low SOC to 19% and It works fine. Sometimes it drops below 19% but never below 15%. I think the hardware has a problem keeping it at 19% but the workaround is doing great on my AC300.

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@hey Thank you, this may be a great workaround, will try it today.

To update, I managed to check the low SOC AC turn off setting today. Set it to 11%, it failed to disconnect AC output power until 1% SOC when I had to do this myself. The feature does not work, apparently. @BLUETTI , please assist with this, if possible.

@Oleksiy I’m very sorry for the late reply due to the Lunar New Year holiday.
A low SOC value will not cut off the AC output.
But at 11% depends on the load and input power, if the load power is greater than the input power, the battery power level will still continue to drop

@BLUETTI Ok, thank you. I thought the meaning of SOC Low setting was to cut off AC power at this level of SOC, as the instruction manual and screen instructions suggest. If this is not the case, such a setting would be very useful - please consider introducing it in the firmware update. It should not be more difficult than stopping charging at SOC High, which works well now.

@hey This won’t work for me for some reason. The AC output won’t shut off even at 1% SOC under SOC Low setting at 20%.

You are correct, the AC output does not turn off. I use my Acc300 as a UPS system and one requirement is that the AC300 stays on until the battery hits 0%. The SOC stops charging the battery when the AC300 hit the low SOC so that is why I set my low SOC at 19% and it is working fine. Never have the AC300 die, yet.
Harlan

Hi - According to the manual and the LCD screen: “Battery SOC Low: When power level drops to this SOC, the combo stops powering loads automatically.” this is the problem everyone is referring to and appears to still be an issue. AC500 has the same issue. AC Load or AC Output does not get cut off when the Battery SOC Low is reached. Unfortunate your response is contradictory as it states the “A low SOC will not cut off the AC output” but then you state if “the load is greater then the input power…” meaning it doesn’t cut off input power either. Based on your response; what is the purpose of setting the Battery SOC Low? What is that setting supposed to do?

@Bizz009
The previous description of the display screen and user manual was incorrect. The load will not be disconnected unless the battery level is below this value. Due to load priority, when the battery level is below this value, the device will try to avoid using battery power to carry the load.
The purpose of setting a low SOC value is to “Preset the battery minimum SOC value to ensure the power station has enough quantity when the grid fails."

I’m not quite following you as you state it was incorrect but then your description is the same as what it states.

“The load will not be disconnected unless the battery level is below this value.” - this is precisely the issue. The load is not disconnected when going below this value. This is what the reports have been. View this link to get further clear information of this issue.

If this is not want you meant then please do provide more info to help me understand what was meant.

Then further;
“Due to load priority, when the battery level is below this value, the device will try to avoid using battery power to carry the load.
The purpose of setting a low SOC value is to “Preset the battery minimum SOC value to ensure the power station has enough quantity when the grid fails.” - yes correct - this is what the documentation states and is therefore the expectation but it doesn’t appear to work. To add to this it should allow one to guard against discharging the battery completely by setting a minimum that cuts off the load to prevent full discharge to zero.

Hi, I’m a new AC300 owner and have been experimenting with this feature. Below is how the feature works as best as I can tell (which does not match the Bluetti menu description, and the Bluetti Admin confirmed above that the menu description is incorrect). The low SOC value takes effect only if there is sufficient grid input power to cover the output load. But because the unit is acting as a UPS, the unit attempts to power the output load for as long as possible. If there isn’t sufficient input power to power the output load, then the unit will drain the battery as needed (even below the low SOC value) to keep the output load on.

The purpose of the low SOC value seems to be intended for using the unit with grid power input and using the charge/discharge time period settings. When discharging the battery during peak-rate hours, greater cost saving can be achieved by letting the battery discharge to lower SOC. But if the grid power then fails while the battery is at low SOC, there would be less available battery power to fulfill the UPS purpose. The low SOC value allows the user to decide how to make this tradeoff.

In the YouTube video above, grid power did not seem to be connected (the “Grid” input isn’t highlighted as enabled). I think this is why the low SOC value had no effect.

I suspect the unit cannot reliably discern whether it’s being used as a grid-connected UPS or as an off-grid battery (grid input power failure looks the same to the unit as grid input not connected). If off-grid situations require the ability to cut off the power output based on SOC level, I think Bluetti needs to create another setting (or another mode that is not a UPS mode).

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