I just got a mower/blower/trimmer two weeks ago. After the first use, everything worked great. When the battery died, I replaced it with the smaller battery to finish the job, but I noticed when putting the dead battery on the charger, it gave the indication it was fully charged. After finishing the yard, I swapped the batteries on the charger and the other battery had the indication that it was fully charged as well. I kept the larger battery on the charger for a few hours and tried to run the trimmer, but it didn't work with either battery. But again, when put on the charger, both are supposedly fully charged according to the charger. Am I doing something wrong or is my charger defective?