I just completed a conversion on a Craftsman LT2000. Yesterday I took it our to mow my lot of pretty thick and tall grass and it was cutting great, for the first 150 feet. Then the power declined dramatically and I limped back to the garage. I don't think my batteries were depleted that quickly (12V 35AH Sealed Lead Ac), but I'm planning to upgrade the pack so I can run longer.
While I was checking belts on the deck I put it back on the charger and 60 minutes later it did the exact same thing.
Any thoughts? Is it as simple as too little battery capacity?