I have a battery tender that I was going to plug it into the 12V accessory port in the left side storage compartment. The owners manual wasn't clear to me if that is how to keep the battery charged. The owner's manual said not to use the 12V port to charge a dead battery. My battery is not dead so I assume I can use the 12V port to trickle charge the battery? I could take off the right side panel and charge it directly to the battery? What do you say?