I have seen reverse on everything of mine. If I keep something charged up or start charging before it's really low, battery life ends up sucking. Computers, cell phones, power tools, etc. My dremel I used to keep on the charger after each use. Battery lasted a couple months now I am lucky to get 7 minutes run timeout of it. My computer I let the battery run down, recharge, then repeat. Computer is 2-3 years old and still has decent run time. Just my experience.