Chainsaws

hi, i just purchased the i120 battery saw 2 weeks ago in leiu of a storm that was supposed to hit my area. the storm never came but i was clearing some brush in my yard and using the saw for the first time since purchase. the battery only lasted about 10 minutes which i thought was odd because it had been on charge all night the night before. i removed the battery and charged it over night again and the next day when removing it from the charger, the level indicator only shows 2 bars. i believe i may have a defective battery. im going to borrow my brothers charger to make sure (i bought his saw at the same time as they were on clearance) but if i have a defective battery, where do i get it warrantied. lowes doesnt seem to carry just the battery.