Im new to this so lets give it a try. I have a 2008 polaris sportsman 500ho. Last weekend, separate wheelers the wife and i tried to ride some trails. Needless to say my sportsman didnt cooperate. 20 miles into ride the battery light starts blinking. Shortly after the hot and check engine come on. We stop have a beer let it cool down. Barely turns over. Ride a bit til same lights come on. Next stop i gotta swap out batteries cause mine wont turn over. Get it home charge battery and load test it. Its good. Fsn works while running and with key in accesory position. I let it run with rad cap off to possibly get rid of air bubbles. I unplug heat sensor. Fan comes right on. When i go in diagnostic screen with atv running it starts at 12 volts charges to over 13 with some throttle. I turn lights on and it brings down to 12 volts. Fan kicks on goes down to 11.5. Carb not efi.What are your guesses? Would greatly be appreciated.

 

Sounds like at 13 volts not charging enough.. Look at the other post you have.