Im having trouble with my batteries in my seadoo jet boat. It has two engines and a battery for each of them. They are small batteries like the ones in jetski's. They are only about 7 months old. They have been run completly down from my kids turning on the lights on and leaving them on all night. Will that ruin batteries? In my main fishing boat I have run my trolling battery all the way down many times and it still is good. Im stumped:crazy:! Any suggestions?