I have an AC180 that I am trying to at least temporarily use it in a way similar to a computer UPS for an always on server that draws around 150 to 175W total. My APC unit failed a few days back and I swapped in the AC180 for this. Anyways I see it’s constantly charging at around 300W with a 175W AC only load and the charging is making negative progress meaning it slowly discharges over days. If I turn off the server removing all but 39W of the load it will switch to charging at around 1KW and this will cause it to charge fully. It’s set to normal mode charging and I have no PV or battery input.
Edit: Interestingly the second the one server shuts down the charging starts at a reasonable rate and > 1KW. I have 2 PCs connected to the AC180. The workstation is off unless I am using it. A few minutes ago I shut the server down with the workstation up and the charging instantly started even though I am currently using over 140W. I will have to do some more testing including starting the server while its charging. It was down to around 48% left and a few minutes later with the server off its over 59%. The server has an EVGA 1000W supply while the workstation has a Seasonic 850W or so.
Edit2: The second I pressed the power on the server the Grid power went from 1.3KW to 400W and the AC output went from 140W to ~290W. The battery was 63% at that point. Also I have tested ECO mode on and off. charging mode from normal or turbo. I have tested power lifting on and off. None of these settings seem to help.
I see maybe 3 possibilities, 1. Grid instability, 2. Interference from the equipment being powered, or, 3. A possible issue with the AC180.
To possibly eliminate 1 or 2 of these I would suggest connecting a different load in UPS mode, perhaps from a different supply, to see if the AC180 is doing the same thing.
I have an AC70 which is connected to my Fibre optic input to the home, the WiFi Router and the home security camera WiFi/recorder. It has been operating like this for over 6 weeks to date.
The load shows 27W Grid input and 27W AC70 output, which = 100% pass through. Battery at 100%. I don’t check it often, but have seen capacity briefly drop to 99% and a very brief charge from the grid of around 275W. This is the approx charge wattage of the AC70 when set to silent mode charging. As I’ve mentioned in other posts this is probably due to the internal smart charger briefly checking the battery’s SOC. I have other chargers that do the same including, but not limited to, Redarc and Victron.
The AC70 is set to Eco mode = Off, Grid Self-Adaption = Off and Silent charge rate.
As an aside, I have 2 fridges in my kitchen, one is a 520lt inverter fridge freezer (main household fridge). The other is an “El Cheapo” 90lt drinks fridge.
I’ve tried both of my AC70s and all 3 of my AC180s on both fridges. The 520lt works perfectly from all 5 power stations in both UPS mode and with grid power turned off. The 90lt starts, stops and stays stopped, on all 5 of the power stations, with or without grid power. It is the only device I possess, that won’t work. So, by process of elimination, you should be able to eliminate 2 of the 3 I noted. In my case it’s the 90lt fridge.
Forgot to mention, the 90lt fridge works perfectly from grid which, every time I check is running at around 241 to 243VAC. My Bluettis all seem to hover around 230 to 232VAC, load dependent, which is still within the range most appliance’s compliance plate. However, just because a compliance plate gives a voltage operating range, doesn’t mean they will. 
Thanks. I expect its #2 or #3 or a combination of both. I probably will do some more testing tomorrow. One easy test I can do is turn the server off and more highly load the workstation. A more difficult test would be to swap power supplies however its a bit of work since they have different modular cable sets.
I suspect it may be at least partially #3 because of when I first got the unit (late November 2023) it made a loud pop sound (like a spark) 2 to 4 times randomly over a period of months but hasn’t to my knowledge done that since. Each time that happened the load was just a high end laptop (230W power supply) and a monitor. I was sitting a few meters away from the unit so it was quite startling. It seemed to work fine with the laptop load and it didn’t appear to do this at all. I have also used it to power a refrigerator when we had a 25+ hour power outage. In that process I took it to a family member (who still had power) 2 times to be recharged so that we could keep the refrigerator going. It worked very well for that.
Did you turn on grid enhancement mode? What is the charging state of your AC180? Constantly charging at around 300W would indicate to me its in “silent” mode. I’ve heard of firmware problems related to the DSP when trying to enable turbo charging. Supposedly there is a software update where you can throttle the charging to I believe 600 or 800 watts. I think there are other factors as well that would prevent turbo charging like battery temp for example. Sometimes the AC180 will throw an alarm for grid oscillation if your power is not stable, henceforth why I recommend ensuring grid enhancement mode is on in advanced settings.
@sealy1986 One thing I have noticed with the AC180 I go camping with. I normally charge only Silent mode, but on one occasion I raised it to Standard charge when at 70% SOC. When I checked the SOC a while later, it was 86% SOC and even though it was set to Standard, the charge had throttled back to around 275W = Silent.
I have long believed that if charge is near zero and set it to Turbo the charge rate won’t necessarily be immediately at that high rate. I think it will slowly increase until at least a certain level of SOC. Then as it fills, again throttle back near 80%. Not knowing what happens with the charge curve at each charge setting intrigues me. So, when I have a little time to spare, I’m going to deplete one of my power stations to almost zero, then recharge it to see what actually happens, and, for each charge setting. That’s gonna take a bit of time, lol.
Edit - At least I know set to Silent it will be a constant 270-280W, so only need to do the 2 higher settings.