Battery

On the discharge side I agree with the 50% state of charge minimum for deep cycle batteries. That occurs at about 12.2V so you really need a voltmeter to measure it properly, the little lights in the trailer aren't very useful, to be kind about it. The 12.2V should be measured with the battery at rest (no significant charging or discharging) for a half an hour or longer. After you take that measurement once or twice and relate it to the lights and to how much electrical load you're been taking you begin to get a pretty good idea what you have and don't have to measure it all the time. 

Or if you want to do it the old school way you can get a hydrometer (they're cheap) and measure the electrolyte specific gravity. Sulfuric acid is heavier than water. The lower the state of charge the lower the sulfuric acid concentration is and the lower the SG is. SG should generally be around 1.18-1.2 at 50% state of charge. 

On the overcharge side the WFCO chargers in our Pods seem to have a tendency to overcharge the batteries pretty heavily when left on which can consume the water and expose the plates in a few weeks. At least mine does that. Exposed battery plates are baaad. 

So check the water level frequently and/or shut the charger off for awhile after you've recharged. Use only distilled water and bring the level back up to the little slots below the caps. If you add water turn on the charger for a day or so to mix the distilled water with the sulfuric acid (which tends to stay at the bottom).

The other killer of batteries is heat. Contrary to popular belief cold weather is good for batteries as long as they are kept charged. They won't freeze if charged well, even in extreme cold. But hot weather will kill them because it accelerates internal corrosion of the battery plates. Nothing really you can do about it, we all live where we live, but don't expect to get the same battery life Jato is getting in MI if you live in FL or AZ