Isn't there a possible problem depending on the type of battery and the type of battery charger if the battery charger is connected and charging for an extended period of time?
The reason that I ask is that about 10-15 years ago I left the battery charger that originally was on my boat
hooked up and charging for about 5 weeks and came back to find that all the water
had been boiled out of the lead acid batteries . The explanation I was given at that time was the charger was the old style or cheap
type that continued to charge and charge regardless of the state of charge of the battery resulting in 'cooking' and destroying the batteries. This also created a serious risk of fire.
search produced this as an explanation:
" A trickle charger can overcharge a battery fairly easily. They run a constant 2A regardless of the state of charge of the battery. For maintaining a charge, you either want a float charger, which maintains a voltage slightly above the battery voltage or a timed charger which cycles on periodically, typically once a day, and checks the current draw by the battery when the charger applies a voltage."
So basically I believe the original poster should be warned (a) it depends on the type of charger and type of battery and (b) you should definitely not leave a battery charger hooked up and charging for an extended period of time and definitely without monitoring both the battery and charger.
Also if the battery charger is being powered by a shore power
cord run into the boat
that again it should not be left connected if unattended as corrosion
will likely occur at one end or another of the shore power
cord (especially in a saltwater environment) which again will result in heat build up at the corrosion
site with risk of fire or damage to the connectors --speaking from experience :-(