Make sure you only swap one thing at a time.
First thing I would do is put the battery on a slow charge for a few hours, and try it again without changing anything. If it's fine for a short time again, then starts to fail again, it's most likely the regulator/rectifier or the battery itself. (Or the wiring in between.)
Don't forget Electrex have kindly let us publish their superb fault-finding guide in the Workshop.
_________________
Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
Check us out on Facebook! Please "like" our page!