Videos: Headlight brightens and dimms-charging system test

the video first start, the reading should be a 14.5+ when idling, you are reading 13.5 ish, low there..

and what about that battery? how old is it and what is it?

you should run Yuasa only, AGM.. very important here.. maintenance free, they are a bit more, $85.00 usd or so but it's what the bike wants, you are dropping to low 11v with key on which tells me its not got a lot of good solid cold cranking amps, inexpensive batteries can strain charging systems as well, best to go with the stock AGM Yuasa..

then if you want to do yourself a favor and beef her up and smooth her out more a Ricks stator and a Roadstercycle mosfet R/R and a direct to battery mod with the inline circuit breaker, this way she get to hot or puts out too much as we see here the breaker will flip till its cooled down and back to spec, won't harm any components.. if your stock stator specs out its good, they are decent stators I spose? but mosfet is best if it doesn't have one already, the inline circuit breaker is nice too..