Re: Battery power

[Bernard Cleyet <anngeorg@PACBELL.NET>]

I suggest you obtain the Radio Shack Enercell Battery (sic) Book, or equivalent
from Burgess, etc.  This book includes construction, chemical reaction, use,
etc.  Apropos to your question, it includes discharge graphs for many types and
sizes of cells.  For example the ones for CR2032 (used in my Cassio Fx 7700GB
graphing Calculator) show the discharge (time and EMF) for loads 6.5 k Ohm, 15
and 30. [respectively, ~ 350, 900, and 2k hours for drop from ~3.3 V to 2.5 @
70 deg. F].  Another graph shows the discharge with a 15 k Ohm load at various
temperatures.  Weight 0.11 oz., 200 mAh capacity (nominal), disk (button) 20 mm
(d.) X 3.2, Li-Manganese Dioxide

For the Alkaline - Manganese dioxide cells ("long lasting" AAA, AA, C, and D),
it gives log - log plots of average service life for six cut off EMFs 1.3 to
0.75 V; hours as a function of load.

I suspect much of this data is available from mfgs' web sites

bc

p.s. Tony Wayne wrote:

> I'm helping one on of my students measure the power output of a battery. We
> load the battery with a 10 ohm resistor across its terminals and measure the
> current through the resistor and the voltage across the resistor. This works
> fine for the AA, AAA, C, and D size batteries. But the button cell
> batteries, for watches, give a decaying current. Any ideas as to how I can
> alter my measurement method to get a steady current from the button cell
> batteries?
>
> -Tony Wayne