07-01-13, 01:48 AM
The Fazer's alternator is normally well up to the task of keeping the battery charged, even with lights and heated grips on... provided it's used regularly and the engine spends some time above 5000 rpm. If yours isn't doing so a few checks with a multimeter should help diagnose the problem. You might have a duff generator, but it's more likely to be the regulator/rectifier or poor contact/broken wires somewhere or a dead battery from standing too long... Optimates are a poor substitute for a decent thrash down a fast road.