I don't think I've commented before?, but the idea is perfectly valid - it's absolutely horrible, and a nasty idea, but it will work prefectly well.
However, I don't suggest it's something you should build, if you're building a battery charger you may as well do so properly - but I can see it might be useful for throwing together if you're stuck with a flat battery one night!.
However, I don't suggest it's something you should build, if you're building a battery charger you may as well do so properly - but I can see it might be useful for throwing together if you're stuck with a flat battery one night!.