Wow... at least I'm not alone. Ugh, that doesn't make it any better.
I bought one of these pieces of junk in May 2007. It was a refurb model at Crappy Tire and it cut my lawn exactly once before dying. I brought it in to the store and they sent it to a local guy for repair. A month later I picked it up and managed to cut my lawn maaaaybe two times. Then the same thing... battery wouldn't hold a charge for more than 2 minutes.
I took this refurb unit back in to Crappy Tire and spoke a manager. He agreed that the refurb unit was a lemon and allowed me to pay the difference in price for a brand new unit. Yay! This one worked for the rest of the season, which was maybe 2 cuts.
Next spring (2008) same old problem. Of course I had stored it as per the manual instructions which, given what I've read above, are wrong. I risked yet another hernia chucking the machine in the back of my jeep. Off for another local repair, I got it back last summer. Shockingly, exact same problem. 2 cuts and done.
Frustrated, I kinda gave up and ignored it until now. I just got back from yet another visit to Crappy Tire to see what could be done. The "customer service" guy was totally clueless and some guy in a suit wandered over. He explained to me that these batteries are "expected to fail after 1 year" and that I should buy a new battery as part of routine maintenance. To make me feel better he also said that this was to make up for the fact that I didn't have to pay for oil or gas. I laughed at him and said it was a joke that Crappy Tire keeps selling these units. He agreed which wasn't really much help.
So now I'm stuck. I have this useless behemoth sitting in my garage yet again. I don't want to waste $150 on another battery knowing that it will die in a few months time. And I can't justify selling it to anyone knowing what I know. Unless I can sell it to a Crappy Tire rep in a suit. That I'd be ok with.