I changed my brushes on alternator not long ago and was charging fine. Drove back from work today and the charge light come on and the battery's drained, do I need a new alt ? As I haven't touch the old wiring at all. The engine was losing revs and power as I was driving it to 

Hi Jake,

              As the alternator you changed the "brushes" on, has no internal regulator, whatever is causing the alternator to not charge the battery, could be the alternator, the external regulator, a fuse, or a fan belt, or maybe even wiring coming loose.

Like last time, first you've go to check everything visually, & then work your way through each item/component that is part of the "charging circuit".

If nothing is visually obvious, then, I'd take the alternator off again, & make sure the brushes aren't the culprit again.

Cheers Banjo