Polaris had a junk run of batteries in 04. I hear they were good about replaceing them, fortunatly mine was replaced when i got it used.
I've had it for a year and a half and it needs replacing again. i keep it in a heated garage and use the winches alot.
They are small batteries and i think a year is about right, My Harley-Davidson went throught them quick too.
Deerkiller

 

No way! I just replaced my original 2001 500 Battery this year. With regular maintanence, use and periodic charging (such as a tender, which are great) You should get at least 3-4 years out of these "small" batteries.
I have 2 older Honda bikes and have replaced them every 4 years needed or not, with no trouble from them ever!
I pull the batteries from my Bike's in the winter, I do NOT keep them on a tender. Check the water level, a good charge, then store for the winter and I get 4 years.

If your needing 1 a year, something is wrong!

 

Make sure your sportsman is not part of the ECM recall. I just found out my '05 was involved in that recall. The ECM can overheat and cause the cooling fan to turn on, even with the key out of the ignition. My quad was fine for a few months, then it went through two batteries in one month. It is at the dealer right now getting the ECM, temperature sensor, and battery replaced at no charge because of the recall. The recall affected 20o4.5 and 2005 models. Here is a link to the recall info.:
http://www.cpsc.gov/cpscpub/prerel/prhtml05/05568.html

http://www.polarisindustries.com/en-...l04_05ATVs.htm