Hi Hugh the hornby controller doesn't have a hugh output so it depends on what your charging, how fast your charging it & what charger you are using as to what power supply you require. As malcom said some chargers wont like the un-smoothed output from your car battery charger,l however i have used several different fast chargers at home powered from a car battery charger for many years without any problems. As I use a spare car battery to power my charger when I'm in the Field,all I do is put the spare car battery on charge, & then connect the model charger to the car battery & u have yourself a fairly well smoothed power supply. Obviously you have to employ some common sense, don't connect the model charger up till there is a reasonable charge in the car battery, & don't leave the car battery on for several days. failing that a simple smoothing circuit for your car battery charger is very easy to build. pm me if u require help with it
hope this helps Glenn.
