I had two float charge battery chargers from Halfords and I left two batteries connected for some months. When I came back to them, one was fine and is still usable a couple of years down the line.
The other, newer one on the newer charger was cooked dry and scrap.
I have now binned the Halfords chargers and use one from Claus Olson.
However I will not trust any charger to be left unattended.
Jon the Chief
