Dirtbike Stator

[spinisr]

Hey everyone - new guy here,

I own a Honda XR200R dirtbike and I'm currently in the process of customizing a headlight. I

purchased a generic headlamp housing from autozone and a generic 65watt halogen bulb. A

negative and positive wire come out of the dirtbike's 12v stator so I simply connected them

to theheadlight. The headlight works great except there is one problem. When the engine is

idling the bulb goes dim and when I reach full throttle, it's extremely bright. What do I need to

install (besides a battery) to keep the bulb steadily illuminated

Thanks !!

 

[Resqueline]

You need to use a bulb that matches the spec's of your dirtbikes stator. Any idea what the original lamp(s) were supposed to be?
A permanent magnet dynamo delivers a constant current, with a voltage only limited by RPM.
Your bulb draws 65W/13.5V=4.8A.
Lets say the stator was made for a 6V 35W bulb. That's 35W/6.8V=5.2A.
Thus the stator overpowers your 65W bulb by 8% (counted in Amps) as soon as the RPM's allows the voltage to pass 14.4V.
8% may not sound like much but a bulb has a non-linear current/voltage relationship (it's draws an almost constant current, relatively independent of voltage).
I don't remember the exact relationship but more current results in a much larger voltage increase, and thus an even larger than that again power increase.
If you want to use a high-power bulb then you need a rectifier/regulator/battery setup to deliver juice at low RPM's.