From the bloggers at Outside Interests:
Most travel trailers are built for weekend use. That mean the factory equips them with a battery or two that is sufficient to power the trailer for about two nights without being plugged in. After that, it’s time to find a source of power.
So it’s not surprising that not long after an Airstream owner begins to travel a bit more away from the KOAs and toward bucolic and private boondocking sites, they begin to look for ways to extend their power capacity. The next step is often a generator or solar panels, and a new set of batteries with greater capacity.
Absorbed Glass Mat (AGM) batteries such as Optima and Lifeline are a typical choice because they last a long time, can be deeply discharged, and are maintenance free.
Then an interesting problem crops up, one that most Airstreamers—and even many RV repair technicians, don’t know about. The power converter built into your Airstream isn’t optimized for charging AGM batteries. Often it will undercharge them, particularly in cold weather.
To read Outside Interests’ review of the Xantrex TrueCharge2, click here.