Just don't overload them, they will happily put out a lot more current than they are rated for.
Lithium batteries pull far too much current.
Halogen bulbs are also too greedy.
Resoldering the armature wires with high temperature helps, but not for long.
I'm using a BPF high output LED now, if you ride slowly, you can just see the road.
I don't think the fish eye lens helps.
