12AWG is designed to carry 20 amps Ac or DC, depending on which ampacity charge you choose to believe..
You asked it to pass 50. How long before its insulation released its magic smoke?
Shore power is 120 volts more or less, inverter is likely less than 12/
volts times amps = watts.
600 watts at 120V is 5 amps
600 watts at 12v is 50 amps.
Amps increasing to maintain the same voltage, Mex told me on the screwy31(flooded marine battery) thread that this was the beginning of thermal runaway.
I've never noticed amps increasing on my Northstar AGM when held at Vabs well past the 'full' threshold. They've always decreased or just levelled off. I guess it is possible the times I expected to see 0.1 amp, and instead saw 0.2a, it had hit bottom and started climbing again and I simply did not observe the ammeter when it went lower as I was likely asleep.
