In regards to batteries. Be careful when not having them on a trickle charger when not in use for a long period of time. All batteries are different. All batteries have a discharge limit. Some are at 50%, 60%, 70%, and so on. That means that the charge in the battery can not go down below that percentage. If it does, it shortens the life of the battery. Also, if it goes below the allowable discharge, The battery can no longer hold a charge or hold the charge for a very short period of time. I go over these calculations when I install battery banks for solar chargers for solar panels. I ran into this problem with my motorhome this past summer. I let the batteries go past its discharge and the batteries were crap. Had to buy two new batteries at 185.00 a piece. Now I take all of them out and put them on a trickle charger.