There is a simple trick for bringing back your dead batteries back to life. A dead battery is not a simply empty battery, but a battery that is either not rechargeable, or has been recharged so many times that it does not hold the electricity anymore.
This video shows you exactly how to suvive your old NiCd batteries, however it can also work with other types.
Rechargeable batteries, especially Ni-CD, create a crystalline matrix over time that bypasses the majority of the chemical makeup of the cells. The initial step of the charge sequence is of the highest power of the whole cycle. Doing this repeatedly breaks up this matrix allowing a normal recharge. A different video uses 3 batteries connected to create a 45 volt “zapper” that accomplishes the same thing.
Note: The skip you see in video is not from editing. It is simply to cut the video length in half so you would not waste your time watching the unplugging and re-plugging.