Last fall, we took a 15-day trip in our 2018 TAB 320, our first trip longer than 3 days. Of the 6 parks we stopped at, 5 had electrical hookups; the 6th did not. When we arrived at the 6th, and started using lights on battery power only, the lights flickered and we immediately noticed that the battery voltage was quite low (10.5 or so). Surprise! We thought we were being proactive by leaving the battery switch in the “ON” position the entire trip, assuming the battery would be charged by the car while we drove and by the hookup while the trailer was at rest. Obviously not – our bad! Can anyone answer two questions: (1) why did this happen? and (2) how do we avoid this on our next adventure? Thanks for any advice!