My mower and my 2.0 amp batteries were purcased in May 2016. Yeterday, the first time I ran the mower this year, the battery in the mower only worked for a few passes before the red light came on. I figured it was the 30% capacity they are at when not used for a period of time. the battery on the rapid charger, which seems to be working great showed the battery had a full charge. I put that battery on the mower and when it powered up, the light was red. I was able to finish the yard with it showing red and it still had power. When I put the mower up, I took the battery off the charger and put it in the mower and put the other battery on the charger. The wife went out to mow this morning. She started mowing and got about the normal amount of mowing done when the light on the battery turned red. She said that she mowed considerably more then she usually can on the red light. It finally quit, so she put the second battery in, that had been on charger over nigh and it ran for about 4 passes and the red light came on. She was able to finish the yard on that battery. What is causing this to happen, any suggestions?