A lot of the newer smart batteries take this stuff into account. When the battery feels ‘dead’ it’s just the smart battery pulling back power to you don’t ruin the battery by taking it too low. I know, with the Dewalts, they tell you to swap out batteries as soon as you notice a difference in the tool’s speed/power. Although, I think some of that is to reduce cycle time on the charger and have the battery back topped up before the next one runs out. I know on my small batteries I can’t install deck boards fast enough to run down the current battery before the previously used one is charged up. Battery technology is one of the next major innovations in the world. 

Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".