AC300 AC output reading 0

G’day all,
I have had my AC300/B300 combo set up for a week now (finally got it, YAY!)
I have 6 devices plugged into a power board (router, modem, smart hub, camera base station, and a Hue lighting hub) and that power board is connected to one AC outlet on the AC300.
I can see in the Bluetti app that the devices are sucking power by the dot moving from the B300 to the AC outlet icons but the Watt meter just reads 0. It use 20% battery in 12 hours so I know it’s working.
Do I not have a setting turned on or tweaked somewhere? If I plug a larger device, such as an iron in, it shows 1200-ish watts. This happens for all 6 outlets.

What is the minimum wattage the AC300 will register on the app/AC300 screen?

Cheers in advance

Your Bluetti will consume power by being powered on. It will consume more power when the AC inverter is turned on as well even if you are not powering any devices. The larger the inverter, the more power it consumes while being turned on. The AC300 has a large inverter. Think of this like leaving your car running in your driveway overnight with a full tank of fuel and when you come out in the morning, the fuel gauge reads lower but the vehicle did not move.

@Scott-Benson thanks for the analogy, I’m a mechanic by trade so I understand. My question however, is why does the watt meter read zero when I have something plugged into one of the 120v outlets and switched on? Should it not tell me how much power is being consumed? It would be like driving the car mentioned above but the odometer not reading the miles traveled.


@Aussie_In_AZ Ive found that the meter wont show an output if the wattage is low draw. (such as the parasitic/overhead draws that Scott mentioned above) With such a large beast of a unit, I would recommend a smaller unit for your small devices/loads. (loads that are pulling less then say 50-60watts?) Congrats on your AC300/B300 setup tho man! I’m saving to get a larger home backup system like the one you’ve got! :metal: Those units are killer!

what specifically are you plugging in and operating on an AC outlet? I don’t personally have an AC300 but if I understand correctly, you need a minimum AC draw before the load will be displayed.

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I bought the AC300 setup mainly for my RV but when not in use I have it in the house as a UPS. Running off it at the moment are all my cloud connected hubs (cable modem, wifi router, Hue Hub, Smartthings Hub, Security camera base station and a Google Home speaker).
I know that each does not pull a lot of power but combined I thought they would pull enough to register on the Bluetti touch screen.
As mentioned above, when I plug something in that uses more power, it registers fine. I was just wondering what the minimum draw from the AC outlets can be before it actually gives you a reading.
From a quick Google search, I have a draw of between 25 and 50 watts from devices being on standby or in use.
Again, I was just wondering what the minimum wattage draw that will will be registered on the screen. Just curious, I don’t think there is anything wrong with my AC300.


Dont know what the minimum draw actually is before being displayed as a load, but the easiest way is to plug in several low draw items unit you get a reading and add all the wattage loads from the individual pieces.

I did the test you mentioned with a watt meter and I do get readings above 60w.
Just in case you were interested, I contacted Bluetti about this and this was their response .

"Thank you for contacting us.

For the AC output port, if your device is less than 50w, it may not show the wattage on the screen. But this is not absolute. It is normal that the screen does not display the wattage between 50-100w"


I’ve got the same problem.
Combination of AC300 + B300 in an off-grid-setup and use it to run a dehumidifier (~ 400 W) and a small ventilation (~ 20 W). I am using a smart AC connector strip to switch the devices on and off remotely and by plan. I am using the DC output of the B300 to power a mobile router.

Sometimes when I do not get enough power from the sun, I run the ventilation only. That drains the battery slowly without showing up on the AC300 dashboard - I just see the SOC slowly decreasing. All good so far.

I have noticed lately, that the battery drains from 100% to below 20% over night, Which should not occur - 20 Watts x 10 hours = 200 Wh, that’s not even 10% of the 3 kWh. When the sun comes up again, SOC starts increasing fast, but it suddenly jumps from around 25% to 100% and claims to be full, which I cannot believe.

My thought is: if the AC300 is not able to detect the correct AC output wattage, it might miscalculate the SOC. Is this the reason why Bluetti recommends to run a complete charge / discharge cycle around once a month?

To do so, I have to transport the whole thing to a location, where I can connect it to the grid and run the cycle to calibrate the BMS again. Any ideas how it solve this problem? I have the idea to add one additional ventilation to raise the consumption above the 50 Watt limit. This would still be sufficient to avoid running dry over night, but it will keep the SOC calculation stable. Haven’t tried this yet, wanted to ask the community first.

Best greetings from Vienna/Austria. Looking forward to your thoughts.

@fra_mono May I know where did you see this notice?

In your case, you can try to do a complete charge and discharge cycle to correct the SOC normally or upgrade the BMS firmware, but a complete charge and discharge cycle is still required after the firmware upgrade.

Thank you for the response.

I must confess that I am not sure anymore if I read it in the official documentation or in a forum. A quick search in my browser history turns up discussions that I have read and that I might quote here, e.g.

I know that the discharge voltage curve is pretty flat with LFP batteries, so you cannot derive the SOC from the battery voltage. Only sure thing is the sudden drop of voltage when it is below 20%. I assume that the firmware tries to keep track about what’s going in and out of the battery to keep the SOC up to date.

The real light load of my use case seems to thoroughly deplete the battery. What do you think about my idea of increasing the load above the detection limit? Might this help the firmware keeping track of the SOC?

What I want to avoid is a regular calibration cycle, as it is unnecessary transport of weight to get the battery near the grid.

Moved the whole system (AC300 + B300) back to a place where I have access to the mains. The battery was completely drained, the system would not restart. Had to kickstart the battery first with a Bluetti T500 adapter. When the AC300 came back to life, I switched to standard mains charging. The SOC indicator started from zero, gained around 1% per minute. It jumped from under 20% to 99%, but charging continued. I waited until charging stopped and the SOC was at 100%.

Now I unplugged the system and plugged in a 1kW electric cooking device. The SOC slowly went down from 100 to 83, then suddenly dropped to 0% and turned off the AC. I ran another cycle, the system reacted almost identical. I assume the battery is already heavily damaged, right?

How can I avoid this? I guess I have to think of a smart solution to handle this use case. For an off-grid system, I need to control the load from the SOC somehow. I manage to collect the power necessary to run the internet GSM router and the inverter via the PV system even in the depths of winter, but when the sun isn’t shining, I need to be able to switch off the payload automatically.

If I see it correctly, Bluetti doesn’t offer any way to access the charge level via an API or to automate switching processes with IFTTT or a similar service. Have I missed something?