Re: 1.5 v batteries - to buy ?

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

At 04:54 PM 1/29/2004, you wrote:

> (1)  The 4 energy cells are not going to have exactly the same internal
> R, and the one with the lowest R is going to dissipate a small amount of
> power from each of the others.
>
> (2)  As current flows between the cells, there will be temperature
> changes which affect the R of each of the 4 cells.
>
> If you stumble upon 4 cells with *exactly* the same R at the ambient T,
> then there would be no mutual discharge, n'est-ce pas?
>
> Best wishes,
>
> Larry
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Larry Cartwright


Pas du tout, mon ami:
If any number of cells connected in parallel showed the same terminal
volts off load,  there would be no leakage discharge off-load.
any terminal voltage disparity leads to an equalizing discharge.

If any number of cells connected in parallel  are loaded with an
output current,  they share the load current in proportion to their
terminal volts and inversely to their internal resistance.

Cells with a soft discharge curve of volts against remaining energy
like zinc/carbon would tend to equalize with less capacity lost than
those with a stiffer discharge curve like alkaline cells.

So I suppose that I am arguing from a model of an ideal voltage
generator, but modulated by its cumulative discharge history,
whose current is also modulated by an internal resistance.


Brian Whatcott    Altus OK    Eureka!