Hi Mohhasco and
to the forum.
I think you may have a problem with the controller itself if the power indicator light is continually flashing.
I have a similar problem with two identical Maypole car/motorbike battery chargers which I have had for a similar length of time
(about 7 years).
With my battery chargers, the standby light should come on continually when it's plugged in and turned on, but they both flash continually when first plugged in and the mode selection button has no effect.
If I leave them turned on for at least 10 minutes, the standby light will eventually stay on continually and then I am able to select the required charging mode.
In my case, I think it could be the result of failing capacitors somewhere on the power supply circuit, it also seems to be temperature related, as it takes longer before the light stays on continually if the chargers have been stored in my cold garage.
I would check the voltage at the controller to make sure it isn't a problem with your battery feed.
(A poor connection or faulty BMS etc.)I suggest that you send an email to Golden Motor China
(sales@goldenmotor.com) to see if they have come across this particular problem.
(Your controller problem not my Chargers.)Alan