Using Dead Alkaline AA Cells to Power Battery Electric Clock

[chemist6146]

I have done some experiments with powering battery clock movements with 'dead' alkaline AA batteries.

If you go to: 


https://www.youtube.com/watch?v=swUT8YKoYow

You will see how two AA cells that are below a Volt may be soldered into a series configuration and, with the addition of an electrolytic capacitor, will power a standard battery electric clock movement, possibly for a very long time--it is too early to say for how long. 

The idea uses the wide tolerance of these clock movements to supply voltage.  In normal use the clock will run with a new battery giving 1.5 or 1.6 Volts and carry on until the battery has discharged down to around a Volt before the clock stops.  However, this sort of clock movement will tolerate 2 Volts and two 'dead' cells in series will supply this and the clock then run all the way down to 1 Volt by which the individual cells are well and truly dead.

Precautions are taken to protect against corrosive cell leakage which is a hazard when alkaline cells are discharged down to a very low level.

You will not find many ideas as simple as this one!

[Paul-R]

I tend to ignore what it says on the casing and put them in a recharger. Most just charge up. Some don't and some leak a small amount of what might be nasty liquid. Care must be taken.