family tradition 0 #1 Posted September 18, 2011 i can't keep the battery to hold a charge. but will start when jumped and stay running. i'm think maybe a bad battery its 4 years old . Share this post Link to post Share on other sites
can whlvr 991 #2 Posted September 18, 2011 you can take it to almost anywhere they sell batteries and get it load tested,4 years is about what a standard garden tractor batterie lasts,of coarse there are determining factors but i think you are on the right track Share this post Link to post Share on other sites
Duff 206 #3 Posted September 19, 2011 Yeah, I'm with Don on this one. Four years is about all you can get out of an average compact tractor batttery, and the 312 charging system is generally pretty reliable so I doubt the problem is there. Duff :thumbs2: Share this post Link to post Share on other sites
rmaynard 14,986 #4 Posted September 19, 2011 Generally the problem on 300 series tractors is overcharging. Since the charging system consists of a single diode, many times the charge voltage can exceed 20 volts. Over time that will kill a battery. If you replace the battery, I would still be inclined to check the charging system. If you are overcharging or undercharging, you will still have a problem. Share this post Link to post Share on other sites
Duff 206 #5 Posted September 19, 2011 Generally the problem on 300 series tractors is overcharging. Since the charging system consists of a single diode, many times the charge voltage can exceed 20 volts. Over time that will kill a battery. If you replace the battery, I would still be inclined to check the charging system. If you are overcharging or undercharging, you will still have a problem. Bob, you've got me a little surprised on this one. I've got two M12's and an M10 on 300-series machines. All three have volt meters, and they all run between 14 and 16 volts at WOT. On the M12's, after I've been mowing for an hour or so the voltage drops back to 13-14. Am I just lucky? Duff :thumbs2: Share this post Link to post Share on other sites