My 2012 5085M is still on the original battery. Never had an issue until a few weeks ago when it was about 20 degrees out and I had to jump start it. I put a slow charger on it after that, and now it seems to be fine again. Tractor does sit sometimes for 1+ month. Real test will be next time it if well below freezing I suppose. Also, I did drain it all the way down once when it was only about 2 month old due to me not wiring a switch for the loader suspension correctly. So all in all, I'd say I've gotten my money's worth out of the OEM battery and will probably pick up another one just like it ($160 at the dealer) once it finally quits on me, which I hope won't be until next winter.