As long as the charger is on the battery the lights will work. As soon as you remove the charger the lights get very dim then go out completely. The battery is new it just seems as though the convertor will not charge the battery and it has no 12VDC output. When the TT is on shore power the lights should work without a battery as the convertor makes 12VDC, correct?? The in line fuses that others have mentioned are a new one to me. I will have to look into that this weekend we I am at the property.