Can anyone help, the battery in my 21 looks like its on the way out, optimate says its weak!!! is it possiabel the rectifier cased this??

basically the other day i switch the ignition on and the dash/oil/netral lights where very weak, once it finally kicked over, (took about 9 goes) the lights where nice n bright and everything looked fine, but, dose this mean the generator is okay, if the rectifier has gone would it start at all, or am i worring to much and its just a fecked batterie??

any help on identifing a rectum fryer problem greatly appriciated...