The worse thing you can do to any battery is let it sit with anything less then a full charge...especially in the cold. Anything more then a week not on a tender can take years off it's life. It should have been on a tender all this time. Get one on it asap and it may take several days to fully charge but let it..and you just might get a few more years out of it. The plates are already sulfated some. A smart charger or tender shuts off when fully charged where a trickle charger never does....and that's bad for a battery. Get a good smart charger or tender and always plug it in when not in use. Just FYI, did you know it takes over 40 minutes of running at over 2200 RPM to put back in a battery what one starting takes out? People starting it and running it once a month for 5 minutes are not doing themselves...or their batteries any favors.