Battery charging on shore power?
 

I know that my Towlite (1995) Hi-Lo charges the battery when I'm driving down the road, but I live in it for 6 months every winter in Arizona.

Does the battery get charged when connected to 30-amp power? Or do I have to charge it up again, before hitting the road?

vid, When plugged into your 30 amp "shore" power, part of that power DOES charge your batteries. If all is working well.. All your lighting is 12 v, except any lamps, tv, etc which are plugged in is 120v. Even after being hooked to shore power for months, I still check battery charge and condition before going anywhere.
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However, check with a multi-meter if the HILO's charger is putting out enough voltage. 12 volts is too low. Charger should be 13.6 to 14.1 or higher. A 12 volt charge will not ever charge 100%.
You 12v lights should always brighten when you switch from battery (13.6 new) to shoreline (14). If not check the voltage.
Any DC outlet or DC power source will work (closer to charger is better) as the charger should always give more volts than battery so no need to isolate the two.

I have a 1999 22L Classic, and recently replaced the converter with a more modern one than came with the trailer. The converter changes some of the 120 volt power from your 30 Amp hookup to run all the 12 volt lights and equipment, and also charges the battery. I found mine didn't do a very good job of that. The modern ones vary the voltage to the battery depending on what the state of charge is. They start at over 14 volts and then step down the voltage in two steps depending on how close to full charge the battery has. All done automatically. A good controller for solar panels charges the same way.

So I think the older converters were not this "intelligent" kind. I found upgrading an easy do it yourself project, as long as you get a converter that fits into the physical space of the old one. Batteries charge faster and last longer with these new converters.

Incidentally, I first found out about this technology when I bought a modern battery charger to use on my car and truck batteries. It also had a refurbishing setting (don't remember the actual term) which has helped extend the life of my batteries.