i took my boat out and it wouldn't turn over at the dock, so i used the jump pack thinking that i could just charge it out on the water. then once out there for about 45 mins running, i decided i would try and turn it off and see if it would restart. it didn't, the jumpack took about 15 mins to get it going agin this time so we went to the marina and bought a battery. was actually only $97, i had called advance and autozone and they were right around the same price. bought the battery and installed it and then it ran great for the rest of the day. not nearly as bad as your day, but still a very nerve racking day.