It depends somewhat on the type of charger you have. If it is an older type trickle charger without any auto shut off, then it will eventually ruin the battery, through overcharging. However, more modern float type smart chargers are designed to leave connected.
So what I am saying is that, just because the battery has been on constant charge, doesn’t mean that it is in tip top condition. Need to take it to a garage and do a simple load test on it.
