SO my T500 left me on the road yesterday....cut off from 80kmh... the battery only gave out 150 milliamps at 12,9v I guess the agm battery didn't last so well but at the same time it blew every bulb on the bike so not under charging but over charging I would assume... all this started when the negative battery cable broke off a few weeks ago didn't stop the bike then but I assume it might have broken the voltage regulator somehow ¨the stator put outputs 20 to 50 v when disconnected from the rectifier so I'd assume that ok. If anyone has any ideas I would like to hear them
The T250/GT250/T350/T500 use the battery as a voltage regulator.
The T500 & later GT250 also have a voltage regulator only intended to limit voltage to 16V — haven’t seen anything about its performance without a battery.
That 16V is too much for AGM batteries. Looks like you probably ruined the battery.
And without a good battery, the voltage got high enough to burn out all of the bulbs.
The preferred solution is to upgrade to a modern rectifier/regulator + a new AGM battery.
Or switch to an old-school conventional battery + make sure everything you have is OK.
There are some forum topics about upgrading to a modern rectifier/regulator. This will limit voltage to around 14.5V. Plus the modern part is a little more efficient so you will get a bit more alternator output.
Let me know if you want to do the upgrade & I’ll find the topics for you.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more
The voltage must have gone up quite a bit since the led headlight that is supposed to be good at 12-36v also blew I also bought a 4 wire modern reg. rec. for a snowmobile or some such. I was not exactly sure of how the original voltage reg. was supposed to work and assumed ((incorrectly) when buying a new battery a few summers ago that an agm battery would do fine well it lasted 2 summers so that's something but thanks for clearing up the correct functioning of the thing
You might have also burned out the voltage regulator.
Also, if your headlight was one of those cheap Chinese clones, then the 12-36V is a claim that may be unrelated to reality.
This morning I was looking for a T250/T350 battery on several parts retailer websites. The T250/T350 does not have a voltage regulator.
Got recommended selections including AGM & lithium batteries. Lithium batteries are even pickier than AGM.
No telling how many people have been screwed over by this issue.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more
at 12,9v I guess the agm battery didn't last so well but at the same time it blew every bulb on the bike so not under charging but over charging I would assume... all this started when the negative battery cable broke off a few weeks ago didn't stop the bike then but I assume it might have broken the voltage regulator somehow 
¨the stator put outputs 20 to 50 v when disconnected from the rectifier so I'd assume that ok. If anyone has any ideas I would like to hear them
I also bought a 4 wire modern reg. rec. for a snowmobile or some such. I was not exactly sure of how the original voltage reg. was supposed to work and assumed ((incorrectly) when buying a new battery a few summers ago that an agm battery would do fine 
well it lasted 2 summers so that's something but thanks for clearing up the correct functioning of the thing 
