1. Boiled off water and smell and hot case means toasted battery. Homicide!
2. When you attach the next one and plug the trailer in...check the voltage at the battery terminals...you should see around 14.5 V. After a few hours of charging...you should see around 13.2 - 13.5 volts. If it does not come down to this level in a few hours...you are toasting the new battery and there is a problem with the converter/charger. Disconnect the negative battery terminal on the battery once charged fully until you get a new charger. Don't leave it on "perk"!
3. I would check your DISTILLED water levels after 2 weeks and see if any is needed. If not...check after 4 weeks...then 6 weeks etc. until it looks like they are getting close to uncovered. It MAY be quite a while if your charger is behaving! You can stretch the interval beyond a month if you're not getting much boil off.
4. When you visit for your water check...bring your voltmeter with you and measure at the battery terminals while still plugged in. As long as you are between 13.2 and 13.5...all is well with the charger.
2015 Georgetown 280DS
2014 Vespa LX150 2014 StellaAuto 125