Charge Controller - Off the grid system question

I'll be setting up an off the grid system in my lannie in the future but I'm curious as to what amps will be firing through from the lannies battery into a charge controller.

Charge controllers come in various amp ratings (how much can be fired through it) and the more amps means the more expensive:

Charge Controllers : Charge Regulators : Maplin

Steca Solar Charge Controllers

Pretty pricey once it gets beyond 10 amps eh?

Off the top of your head does anyone know what the amps might be on tickover?

I'd use my little multimeter but it'd blow the fuse.

Thanks