just open your right side fairing (back fairing) you will now see a couple of wires taped together (wiring harness). remove the electrical tape and search for Y/R wire (yellow/red). when you see the y/r wire, cut it and tap it to the brown wire.
Note: the y/r wire that goes to the head light assembly is the wire you should tap to the brown wire, not the y/r that goes to the rectifier/regulator just let it disconnected and put some electrical tape on it for safety purposes. when its done, all your electrical is now battery operated.
Note: you need to change your light to LED lights specially the brake light to lessen the battery consumption, because our battery can't handle all the electrical loads of our mc, thats why you need to change some of your lights to LED lights.
-theres a lot of technique on how to convert stator driven to battery driven specially here on T135, just keep searching for the right thread and choose what is the best for you.
if you really don't know how to read a wiring diagram or you are not familiar with it, let the motorcycle specialist do the job.
-Good luck to you sir... enjoy your mods...