Battery Charger

a very rare occurrence going to a cara park but when I do I use the 240 pwr to charge the 2nd battery through a charger. It is supposed to be smart enough to shut itself down when not needed. rgds

I think you would leave it on till your battery was fully charged then turn it off

If you have a modern caravan it should have a combination power supply/battery charger – not an ordinary battery charger.
Whilst connected to 250v your 12 volt lights will run off the 12v power supply circuit and not the battery.
The battery charging circuit will, once the battery is fully charged, switch to its maintenance program and its 250 volt input should be left on.

In my van everything is 12V except the aircon. The batteries are charged by solar or by a charger if on 240V (usually solar is enough - don't have any electrical connection to tow vehicle)

If we connect to 240V all it does is operate the battery charger to keep batteries charged and allows operation of 240V power points without the inverter. The fridge etc continue to operate on 12V

As mentioned I would leave your charger on to take of batteries. I would have thought that when connected to 240V is the only time your charger will operate anyway.

Alan

My smart charger stays plugged in and switched on at 240v outlet, so that when I either use a carvan park's power or rare occassion have to run gennie it will always charge the van battery. Even if it is only to "float "the battery.

I wouldn't worry too much. however, if it does come across that the battery is full I will switch it off.

It depends upon the charger. If it is a quality multi-stage model then they are designed to be left on. When they are first switched on they go through the charge cycle and when they are finished the cycle they reduce their output to a float or maintenance level. The float charge is just sufficient to keep the battery from self discharging.

It its a cheap one it could be just a taper charger. Those types will over charge the battery if left switched on and boil the battery dry.