hello everyone i gotta question i just bought 3 new everstart batteries last week and fished all weekend sat night i charged the batteries up went out sun came home and pluged the charger up well today i was out checking everything out and when i lifted up the lid my trolling batteries were all wet so i checked my other battery and it was wet as well 2 batteries are for 24volt tm and other battery is for cranking i have a 3 bank onboard charger that i was told to leave pluged in all the time so should i leave it charging all the time and what caused the batteries to sweat so bad i do have the boat cover on all the time also so does this sound norma?l thanks 4 taking the time to help