Originally Posted by Francisco
As far as I know the univolt is working but I think it fried my old battery. should I upgrade the whole system or just buy a new battery for the time being?
Welcome to the forums!
"As far as I know the univolt is working", but the old battery is dead and you think it fried it! As a philosophical comment, if the univolt isn't keeping the battery charged when plugged into shore power, it isn't working. And if it fried the old battery, it isn't working very well!
You can tell pretty quickly whether the univolt is working just by measuring the voltage at the battery terminals with shore power connected and disconnected. A fully charged battery will show between 12 and 13 volts with shore power disconnected and 13-14 volts with shore power connected.
In any case, modern multi-stage converters don't cost much, take ever so much better care of your battery than the old iron ones, and weigh 50 to 100 pounds less. As far as I am concerned, change out the old one when you replace your battery. The old one will make a good boat anchor.