Leisure Battery overcharge

Hi , I like to keep a dehumidifier in my van over winter, preferable plugged in all the time but set fairly low, however this had the possibly of overcharging the leisure battery, I've tried knocking off the switch in the electro block but this doesn’t seem to isolate the battery. Any ideas, apart from disconnecting the battery which is a bit of a pain! or perhaps putting the whole thing on a timer, which isn't ideal for the dehumidifier.

Try leaving a light on?

Disclaimer: The following seems to be working for me, but please be aware that I am new to this and could be making a terrible mistake.


I have had my motorhome plugged in for a month or so. My battery is not overcharging. The charger should just stop charging once the battery is full.

But do check this yourself. You are right to question this!

Also important to note is a plug in dehumidifier is designed to work at room temperature and can freeze up at around 10c (Check your model). You will probably also need to run a heater.

I have a small 500W oil filled heater, which is on it's lowest setting, uses about 100w per hour and keeps the temp in the van above 15c.

I run the dehumidifier 1 to 3 days a week depending on the weather. I have a humidity meter in there and aim to keep the relative humidity 40% or bellow.

This set up is costing me about €2.50 a week and the motorhome is bone dry.

Vans with solar panels fitted are constantly charging the battery without over charging them so i assume mains charging is the same

Thanks for all that guys, very informative !! Cheers