Guys, I have a 2003 Polaris Sportsman 500 HO.  Recently when plowing with the lights on, the lights would only stay on for about 25 seconds and then ALL power was lost including the speedometer pod, the lights, winch, 4wd, etc.  The engine will keep running, and in about 45 seconds all electrical power will be restored.  If I shut off the lights everything works fine.  

Any advice?  

thanks    

sounds like your stator is going bad.
or the cdi box or voltage regulator (whichever your atv uses to maintain proper charging voltage.)

not putting out the proper amount of voltage and it runs the battery down until you tirn the lights off so it can rebuild the battery.

if it's even 2 volts lower than it should be it will do this.

check with the dealer to see what the proper charging system voltage should be then test it with a meter both with the headlights on and off. to be sure it's getting what it needs.  

The stator puts out ac and the reg turns it to dc and sets the volt amount it needs for bat at 14.5  in my book ?  

you should be 14.5 at 3100 rpms. that just tells you that your charging system i working. it sounds like that might be your problem. but wolf is right you should have your voltage regulator and cdi checked.