Using AC300 24/7

I have an AC300 and 2 B300 batteries. I have 1600watts of solar out back on a ground mount. I had an electrician wire in a 10 circuit Reliance Pro/Tran2 transfer switch last week. The plug to feed the transfer switch is in a utility closet indoors because I did not want my Bluetti left out in the garage (Florida heat & humidity). I am not too worried about grid charging, I’ve read all about people having issues. I do not have any GFCI breakers in the transfer switch however, so as far as I am concerned, it wouldn’t affect me anyways. My concern is building up the confidence to leave this thing running 24/7 even while I’m not home. I have seen the youtube videos of people doing exactly what I would like to do. But I don’t know if those people use the AC300 FULL TIME to run their loads in the transfer switch. I am only running 120V circuits in the switch, I’m not doing split phase nor am I worried about it in the future. I don’t need my 240V stuff running on the Bluetti. My other concern is leaving the PV charging cables plugged in 24/7. Anyone else doing this? I am going to run the PV wires in conduit into the closet to feed the bluetti and the bluetti plugged into the transfer switch to power the house. Again, I want to use this full time to offset some of my power bill and mainly to gain the confidence that I can trust this setup to power my house for as long as I need it to. Thoughts? Anything I need to be on the lookout for or worried about? I do not want to screw up my AC300 because I have seen how long it takes support to help with anything, so I’m trying to do this as safely as possible so I don’t run into issues.

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following… same questions.

The best idea to help build your confidence is to ask you insurance guy if you are covered if the Bluetti catches fire.

There is quite an idle power loss with the AC300. I bought one as UPS and, while it works, I ended up using my AC300 mostly as offline backup instead of having it on 24/7.

The AC300 (And other Bluetti devices) have a limitation that the internal electronics always run off battery power. Even when utility power is fine. This causes the unit to permanently go into small charge/discharge cycles which will, in the long run, cause wear on the battery.

I’m not worried about the unit catching fire when used 24/7. I think Bluetti has built a lot of safeguards in their units. The chance of having a unit failing into an off/error state is greatly higher than the unit blowing up or burning out. But having said that, no electronic device is 100% safe. A TV can catch fire as well.

What are your thoughts if I never use AC wall charging and only have PV coming in to charge it? I know just being on, it will use some kind of battery power. But once the sun goes down, the batteries will be powering the loads and the idle power loss you speak of, but will then get charged back up next day when the sun comes up. So I get during PV charging, it is still wasting energy on some internal components, but do you think it’s still jeopardizing the life of the battery as much as a 24/7 UPS function would? I’m not really using it for UPS. I’m legit trying to use it to just run everything 24/7 and charge with only solar.

I think this is where the AC300 is designed for in the first place. LiFePO4 batteries can take a ton of charge/discharge cycles and you will be saving a lot of money by using off-grid solar power this way. Just make sure the sun is powerful enough to keep your AC300 charged up during day time.

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I have an AC300 plus 2 B300 batteries that I use 24/7 to power most of the kitchen (fridge, gas range, bread maker, wheat mill, toaster, water kettle, and occasional other loads). Sometimes I have to switch to the grid if we have two or more rainy/snowy/total-cloud days in a row. I don’t know if I would leave it for multiple days unattended. If I was going out of town for a few days I would probably put those loads back on the grid. My concern is not fire related. My concern is if there wasn’t enough sun to maintain the batteries.

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AC300 running full time since last May. Recharge via solar and 30a generator output.


My AC300 & 4 Batteries have been powering 2 refrigerators, a freezer, and all my computer “stuff” since last fall. It is on 24/7. The purpose for buying it was to insure that our food stays safe if/when the power fails, not to sit it in a closet.

I put it in “Standard UPS” mode at night and cloudy days. I put it in “PV Priority” on sunny days. I am hoping the slightly cheaper power bills will help offset some of the cost of the AC300 system over time.

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I wouldn’t worry about the batteries. LiFePo chemistry batteries are extremely durable with charge cycles numbering in the thousands. You could discharge and charge those batteries every day for 10 years and still have 80% of the original capacity remaining.

As for keeping the PV system plugged in all the time that shouldn’t be a problem either. Most people don’t shut down their solar systems except when doing work on the equipment. I certainly don’t. My AC200Max is plugged into 800W of solar panels 24/7.

The only thing I’d watch out for is to keep the load on the inverter at least a bit under the rated maximum of the inverter. If an inverter were rated for, oh, 3,000W, I wouldn’t push it higher than 2,500W or so for more than a short time.

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I have a question. Have you used this and it’s working fine, is that correct?
The reason I am asking is Bluetti has told us over and over they will not allow their “neutral” to be bonded to the house neutral. When your electrician installed this, he would have connected the “only neutral” coming from the pro/tran2 to your house panel. This would “bond” the neutral from the Bluetti to the house, exactly what they said could not be done.
Can you confirm you have no issues with the Bluetti, Thank You

how is the AC300 connected to your loads? Separate panel and transfer switch?

Manual 10 circuit transfer switch.

I haven’t any issues running the loads via transfer switch. I think the issues come for people who are grid charging at the same time as feeding a transfer switch. I’m not relying on grid charging, just solar.

No transfer switch, just straight to the AC300.

The AC300 has a genius setting to take care of that automatically. I was pleasantly surprised to find that option, and now my AC500 runs 24/7 like that.

Set the UPS to “PV Priority” and whatever % you will allow the batteries to be drained to. Default is 30%. Plug the AC300 into your wall outlet. It will run off PV/batteries until they fall to say, 30%. Then it will automatically switch to grid power until the sun comes up and recharges them above the 30%, then automatically goes back to PV/batteries.
To me, that should be a featured selling point. Your Fridge, etc will NEVER lose power.
I’ve got mine balanced out to where the sun comes up just before it would switch to grid power. I’m about to add ten 100 watt panels to my system so I can plug in more gadgets. Eventually I’ll need to get a transfer switch so I can use the house wiring.

I’m afraid to use any AC charging with my transfer switch simultaneously. Sucks because I would like to have a UPS mode work, but I’ve read too many horror stories about people frying their ac300 by wall charging and feeding a transfer switch at the same time. I’m hoping to rely on solar and battery full time. I will unplug it completely if I need to wall charge. Rather be safe than sorry seeing how terrible the support seems to be when an issue arises.

I have been running dual EP500P (very similar internals to AC300) Split Phase enabled on Bluetti Smart Home Panel with solar and grid charging for several months powering my critical circuits.

I don’t run on batteries overnight (custom ups mode), but automated turn off grid charging during a few hours of the day to run on solar. By the end of the day, I have it such that solar charges EP back up to about 95%. I’m relying on it for emergency backup for grid failures but also using time controls and HA automation to make the best use of solar power.

There had been a few issues initially which were resolved with safety upgrade module for Smart Home Panel and new EP device. I still have issues running high inductive load (vacuum) on the critical circuits (I just use it on other circuits now). Other than that everything works. While I’m more comfortable with it now running 24/7, I still do have reservations about leaving it operating while out of town on vacation, I plan to shut it down and run from grid (spring break).

It would be interesting to see if anyone in similar situation has worked up the confidence to leave it for long vacations.

My dual AC300 Split-Phase system ran my house 24/7 for 9 months. The AC300 in split-phase works great as long as you don’t use the “grid” to charge your AC300, meaning solar/battery only. If you do grid ac-charging your system may experience unexpected outages from surge loads.

Now, my system is different than yours, because I have a transfer switch that isolates the neutral, meaning that the neutral wire is switched when I’m running on “generator” power, aka Bluetti power. Your Pro/Tran2 switch does not split the neutral wire, which means that your sharing the neutral system from your main breaker panel. Now this isn’t an issue if your strictly using your Bluetti for emergency backup power… however, if you’re running your Bluetti in parallel with an active grid then your risking increased voltage, alternative paths back to source (if you grid-charge your AC300) and other random issues with your grid side GFCI/AFCI outlets.

Now you’re going to get the comments from others that “My Pro Tran works fine for me, so it should work for you too”… but two things 1) each environment is different and is used differently 2) it doesn’t mean that they won’t experience an issue, or worse, a fire in the future…

Now with this all said, depending on the age of your AC300, the newer ones have a fix for the “AC grid charging” issue… if yours was bought before June/July of 2022, then I would suspect you have an older first generator one.

If you have an older one, the issue with grid charging, is that you create an “alternative path” back to source and the higher amperage that left your AC300, to service your loads, returns on the AC Grid charging cable, caused by grid pass-through. Again, my older AC300 did not experience this because I have transfer switch that breaks the neutral and there is no alternative path back to source created. Your transfer switch does not break the neutral, and if you have an older AC300, then you have a high chance of frying your AC300.

I am now running a dual AC500 system, 24/7 for 70% of my home. If anyone is considering the AC300, because they don’t need the power from the AC500… still go with the AC500. It’s vastly improved over the AC300 and more stable.


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@EZGeneratorSwitch - You’re correct. The first edition AC300 did not support sharing the neutral with the MAIN. They made a physical hardware change to newer AC300’s that allows for it… thus why you see them now selling the Pro/Tran transfer switches with their units.