The other day, I was driving the Ram to Goodwill and I was stranded. The truck would not start. What I had to do was tighten battery cable and it worked fine. Off I go, no problem until yestersday. Yestersday, I made the mistake of leaving lights on for 3 hours on my truck. My neighbor warned me and I went right away to turn them off. Seems like damage was done. The truck would start, but not hold charge. Obviously, I'll need a new battery. What I would like to know is can a person ruin alternator by leaving light on truck?? Truck does run but won't run unless my foot is on gas. Would a poor battery force a person to have to keep foot on gas to hold battery charge??