When you apply shore power, but with battery disconnected, are you getting anything out of the Iota leading to the battery terminals?

My converter pretty much constantly outputs 13.6V no matter what condiiton the battery is in or what the loads are.

 

There is no reading at all on shore power with no battery. The manual isn't clear, but seems to say that the charger checks the voltage before applying charge. Obviously doesn't do that too well or it wouldn't have fried the original battery. It's always done that, by the way.

When I bought the camper, I tested output with no battery and got zero. Finally tried comparing the battery voltage while disconnected from camper vs. connected to camper with shore power and could see the voltage difference.

I still need to go out and check on the battery status and see if it's charging OK, but I've been getting home from work after dark.

 

My converter is a WFCO, not Iota. It will boil off the battery water at 13.6-8V if I leave the trailer plugged in for a long time. And this happens when we're in Florida over winter. I don't think it's really designed for long-term continuous usage with 110V.

AFAIK the stupid thing is trying to do two things at once. Provide 13.6V to the trailer utilities, and keep the battery charged up. But 13.6V is too high for long-term battery maintenance.

Ideally, the two functions (providing 13.6VDC and maintaining the battery) would be isolated. I have another converter that I may install to maintain the battery and just disconnect the WFCO from the battery when plugged into 110V. Or I may do the same with a solar charger, again disconnecting the WFCO from the battery when plugged in. We'll see.

 

Well, the voltage at the battery, while on shore power is 13.40. Goes down a bit when disconnected. I read the Iota manual again, and it says that the float component is optional. I have to find the unit and examine it for an indicator light to tell for sure.

Sounds like Brulaz may have nailed the issue. It could be giving full voltage to the lights and battery, full time.

 

I had a similar situation but my TT is a 34' Montana tag with two 12v batteries hooked in parallel. The first time I used it I boiled 1 of the 2 batteries. I checked the battery and it had a bad cell so the charger wouldn't turn off. Since both batteries were same type and age, I just replaced them both and no problems since. I'm betting that your old battery had a bad cell and the new will work fine based on what you have said.