AC300 24v output troubleshooting

I have a Unique 12v/24v fridge hooked up to the 24v output on my AC300. It’s was working great for almost 2 years. Found it one morning with no power. Pulled it out, unplugged it and plugged it back in and it started up again. A few weeks later it went out and wouldn’t come back on.

Since it’s out of warranty, I opened it up and checked the inline 15a fuse. It was fine but I swapped it out anyway. I verified with a multimeter that there was 25.5v at the compressor controller. I ordered a new one and swapped it out with no luck. Same issue, no power (compressor doesn’t turn on and no fridge light. It acts like there’s no power to it.

I have tried bypassing the thermostat with no luck. Just not getting power. It did randomly come on and work again for less than an hour.

I’m fairly certain there is no issue with my AC300 since it ran fine for 18 months but I want to rule it out. Is there a possibility it’s cutting out for a fraction of a second at start up? How would I capture that?

As far as I know no, 24 V output could work or not and in the latter case you will have a warning on the AC300.
Is it possible your fridge has a broken thermostat that prevent the compressor from starting up?

Thought about that too. I made a jumper and bypassed it (common troubleshooting step for these BD series compressors), no go. :(

Second thing I will try it will be to try to power on the compressor by providing power directly to it. Is that directly drived by DC current or from a frequency drive?
Also, if you have access to the motor stator pinout you could check their resistance value with a multimeter to check if you get a certain resistance, or an open or closed circuit.

Since there is no interior fridge light on (separate from the compressor circuit) and you are measuring 25.5 VDC at the fridge controller I would think you have a bad main board. I would also try another source of 12 or 24 (AC charging brick / auto cig socket) as well as another cord to rule that out as well.

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@eveljkov You can test the DC output voltage with a multimeter, or click the DC output icon on the screen to take a look.

I ended up pulling out my backup AC300 and had the same results. I called an appliance repair company and they tested the resistance at the compressor and it was the same across all three pins. He declared the compressor dead.

Less than two year old Secop/danfoss compressor dead. Got an extended warranty on the new fridge I ordered. Unfortunately, Unique still has the most efficient fridge/freezer combos so I went with another one hoping this one was a fluke.

I would appreciate your help in explaining how you connected your Unique refrigerator to the AC300 24 volt plug? Can’t find any suitable connector on Bluetti site. I have a Unique 290L refrigerator. Any pics and suggestions as to parts would be greatly appreciated. I am building out a cargo trailer and will use the Unique 290L and my AC300 + 2 B300’s.