Thanks Erik. I checked, and had misunderstood the email, and Bluetti will indeed provide a shipping label.
Happened to me just now as well. Ac200p located in a dry room in my house.
Connector fused like Daimler & Benz
I have to say my thoughts of your product and reliability as a company as a whole are deeply distributed.
Looking at the images from others, the choice of cable gauge and connector type + power board just makes me shiver. It is very obvious that this was bound to happen.
My room was rather cold for a summer evening (28 degrees °). I do not want to imagine what happens if you dare to charge the device in a heated camping van or, God forbid, in the sun.
What happens now?
Looks like the plug was not firmly placed in the socket which caused excessive resistance and heat and melted the socket.
The unit was stationary for the last year and the plug firmly in place. I know this because the unit was placed next to a wall with just the power adaptor plug between the unit and wall as I wanted to avoid tripping over.
Anyhow: if you think you’ve identified a possible point of failure I’d ask why you would use such a fault proven connector in the first place.
What really should be there is a connector that only charges, when locked.
It makes no sense to have a xt60/xt90 connector on the inside of the unit and the use a barrel jack connector on the outside. Unless of course the charger you are supplying is a standardized Alibaba charger that came with a barrel jack type connector.
I didn’t use a connector. I purchased units just like you. However I would agree that particular type of connector running a high amperage for an extended period of time does not appear to be a solid connection as some other alternatives. The reason for the heat is resistance which usually is caused by a poor connection.
I think it’s BLuetti’s feedback / learning curve: DC7909 connector with probably loosening over time… and creating a risk of overheating, unreliable touchscreen over time…
and if you look closely, on the new models we no longer have a touchscreen but a standard screen and sturdier mechanical buttons… and less if not more DC7909 connector.
PS I have 2 AC200max, I am aware of this problem and I check from time to time with a (cheap) thermal camera the DC7909 connector under load via the T500.
What happened to you frightens me a little and I’m sorry for you.
At the same time I’m reassured a little because the plastic melted but didn’t burn (even if unsatisfactory)
Hm it certainly is a welcome twist, that the unit did not burn to the ground. I wonder though, what the actual safety mechanisms are here.
There obviously is no temperature sensor in the loading side of things which I find highly problematic.
Is there knowledge of an RMA process for the affected units?
Will Bluetti offer replacement units?
I have no proof of purchase since the unit was a gift.
From my point of view I ran the unit in optimal conditions, stationary, no movements, etc in a place where no human interaction took place. Simply constant charges during the day and discharges during the night. Unit always on.
If the connector is not up to the task there should have been a warning on the unit.
Besides that all: do you guys think the charger itself and unit is still ok/salvageable?
For your last question: I think the t500 adapter should still work. If you can unplug it from your ac200max, you can test the charger, to see if it turns on and you can measure the output voltage with a voltmeter. For the ac200max, in the worst case the charging circuit is damaged (what is certain is that the dc7909 connectors are damaged), I think that the rest of your ac200max should still work.
You are right, it will be a plus to measure the temperature/to have security on the charging circuit… However, Bluetti has put at least three temperature sensors in other places (we see the measurements in the hidden menu)… If the cells were too hot, I think a safety/alarm would have been triggered.
You can try turning on the ac200max and looking at the fault log to see if your ac200max has an issue.
Important point: you can charge the ac200max via the ac200max solar input, with an ac dc adapter (your t500 if it still works). You just need adapters like DC7909 female-MC4. Pay attention to the polarity of the solar input (Check or replace the dc7909 male connector of the t500 before).
For other maintenance questions… I advise you to report the problem via e-mail with the Bluetti’s After sales service of your country. They respond to you fairly quickly, and there is a Tracking Ticket.
Thanks for the detailed response! 
That’s an excellent suggestion. I wonder about efficiency, though. Am I right in the assumtion, that with the charger connected to its “regular” port, no voltage conversion takes place inside the unit?
The Solar input lists 35-150V input, so there has to be some step-up step-down conversion be in play.
I can measure this energy efficiency for you! I actually have the DC7909 female-MC4 cable which allows me to recharge an AC200 max with 2 T500 adapters (one via the solar input and one via the DC7909 input). I have already measured energy efficiency with the DC7909 input of the AC200 max + T500 of around 89%. I will do a quick measurement when I power the AC200max via the solar input.
Wow, thanks. Highly appreciated!!!
With the same t500 and ac200max adapter:
-energy efficiency via dc7909 input: 89.7%.
-via solar input : 90.4%, so it’s a bit better! (remember in settings to set the solar input to “other” and not “PV” (to disable the mppt). Pay attention to polarity.