Your lights are 12VDC and run from both your converter/charger unit or the battery. Sometimes if the battery is going bad the converter/charger is trying to keep up with it and power surges.
The first thing to do is check the fluid levels in your battery. If one cell is empty and the battery case is warm to hot then you are probably experiencing a failed cell in your battery.
You can also disconnect your shore power connection and read the DC voltage across the battery terminala... It should be around 12.5-6VDC for a charged up battery..
If you battery is reading below 10.5VDC then it may be toast now...
Roy Ken
My Posts are IMHO based on my experiences - Words in CAPS does not mean I am shouting
Roy - Carolyn
RETIRED DOAF/DON/DOD/CONTR RADIO TECH (42yrs)
K9PHT (Since 1957) 146.52M
2010 F150, 5.4,3:73 Gears,SCab
2008 Starcraft 14RT EU2000i GEN
2005 Flagstaff 8528RESS