Same Issue, the above is not an answer.
What causes the "power issue" to flash. "power line" "powerline"
It isn't the power the power is fine, tried in multiple plugs.
Are the batteries unable to be charged,
Is it just a case of toss the charger.

I gave it to someone to use out in the sticks and suspect it is something to do with fried from not using a quality regulator off a generator.

Measure the output voltage, if it is low then you must replace the charger, they don't sell parts to repair them.