I use BT Jrs., .75A on everything I own. Had 2 on the Class A. I would turn those batteries off because they had disconnects and then plug in the Jrs. On everything else they just get plugged in and left to run. In the shop right now there is one on the hybrid trailer, the tractor, the DR grader, the mower, both boat batteries and the 03 Santa FE. In the house garage there is one for the UTV I use to run around the property. Everything but the SF and the boat have original batteries and the boat batteries were 5 years old before they got replaced. Best thing you can do to extend the life of a battery is to charge it slow and keep it maintained.