It has been suggested that if you want to leave a charger plugged in, it is best to have it on a timer instead of just leaving it on 24/7. For maintenance purposes 30 minutes-1 hour a day is plenty. Otherwise, it is safer to just charge it up after use and plug it back in the day before you are going out.Jim EbarbMany, LA (Toledo Bend Lake)2004 Cougar/ 225 OptimaxHumminbird Helix 12 Chirp SI on BalzOut Mount at bowLowrance HDS 7 at bowHumminbird Helix 12 Mega SI on Ram Mount at ConsoleLowrance HDS 8 in dash at console