problem is battery won't hold charge. I just purchased a new battery for my ski and it was good the first day then the next day it did not want to start. it will start with a jump and run all day when at the beach. I can shut it off and restart at the beach but the battery light does blink on and off when doing so. when i take it home and flush the system it is fine but if i decide to take it out the next day it won't start. so basically what im looking for is there some kind of system that still runs when the key is out and the main switch is turned to off. any ideas.