I use a Canon 60D with original grip and two genuine batteries. Twice now in the past couple months, after I charge the batteries until they are fully charged and go outside for a photo session, I am getting surprised that I have zero charge in both batteries. I also tried disconnecting the grip and inserting one at a time, but nothing helps.
Am I doing something wrong? Or is it just time to get a new pair of batteries?
Batteries store electricity via chemical action. An excess of electrons accumulate on the body of the battery and that segment is connected to the negative ( - ) terminal. In contrast, a deficit of electrons are present on the positive ( + ) terminal. Nature abhors such an imbalance. The natural tendency is for the electrons to migrate and neutralize this imbalance. The battery structure opposes this migration. It cannot be stopped, but it is slowed down by the internal resistance in the battery. After perhaps 100 cycles of charge and discharge, the chemicals that do this deed are so weakened that a sufficient charge can’t occur, plus the internal resistance is now weakened, and migration happens quickly. Time to replace the battery!