[sourdough]

So you won't be disappointed or caught in a bind, I would replace the battery and forget filling and charging. After being depleted to the point of no water, and sitting in the trailer with the converter trying to charge it, the reliability of the battery will be questionable at best, or, it just won't hold a charge. Be sure and look at the water level (frequently is using a lot) and keep it (them) topped off. A low battery can cause some quirky stuff.