Battery Conditioners

[raceboy]

As I seem to be using my car less and less (which kind of makes you wonder if spending a shed load of cash on a new one is a good idea ) I think I ought to invest in some sort of Battery Conditioner to keep it in tip top shape so it's ready to go on that sunny sunday once a month when I get chance to use it
Anyway I've seem them at anything from £11.69 to £70.00 I'm guessing theres quite a bit of differance between those 2 units but how much different can they be
So what are you lot using, and just what is the difference

[raceboy]

So what does the £70 Leven one do that the £45 one doesn't, at £70 I'd expect the thing to have a cup of tea waiting for me in the car
And what does the £45 leven one do that the £11 one doesn't