If it has a converter that transforms 110 to 12V, then yes, it most likely also charges the battery on its own. But, your trailer is old enough that I don't know if that converter will supply a "float" charge when the battery charge is complete. If not, you would probably damage the battery by keeping shore power plugged in all the time.
And, a standard "trickle charger" is no better. You need a "battery maintainer" if you're going to keep it constantly connected.
In my opinion, the
Battery Minder is the best choice. It goes into the "float state" when charging is complete, AND, it applies a pulse modulated input that acts to "desulphate" the battery, which will improve it's ability to both accept a charge and deliver current. In addition, the newest ones have a temperature probe that adjusts the charge rate to the ambient temperature. You don't have to worry about boiling a battery with one of these. Here's a link to one from Amazon:
http://www.amazon.com/BatteryMINDer-.../dp/B00D7HZ6FC
- Jack
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