i have an ac500 with a single B300S battery,
this was working fine and was sat indicating 28% on the bluetti app, via bluetooth.the solar panel was connected to the AC500 but indicated no input wattage to the unit as it was dark.
both the green power lights were illuminated on solid green
I decided i would charge the battery by plugging into mains voltage, on doing this the power button on the AC500 went out ( im not sure what the power button on the B300S did)
On attempting to re start the AC500 I noted that the power button does not illuminate at all and the power button on the B300S illuminates solid for aproxx 4secs then flashes 12 times the goes out, this carries on happening each time the set up is trying to start. the AC500 screen is blank and bluetooth can no longer see it.
I have tried the interconnecting cable in different ports with no effect.
If the B300S is disconnected from the AC500 then when pressing the start button the battery appears to stay on and the dc output can be switched on.
I then charged the Battery upto 100% and it is still the same.