Re: Impedance &c.

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

Sad to tell, the energy storage time of cells is only too finite
before self-discharge.

But you may have noticed that the "Best Before..." dates are
growing longer-dated for alkaline and lithium.
So now, it is not exceptional to see forecasted 10 year shelf-lives
 (and that would I imagine be to half or third energy capacity)

 ...so there is still a place for that old joke about the mathematician,
the physicist  and the engineer whose punch line runs ...
"near enough for all practical purposes..."

 which for a battery would be where the load resistor is  between
 X100 and X1000 of the cell's internal resistance.

If an automobile lead-acid battery can run a starter motor
at several  hundred amperes, then the internal resistance
might run to 50 milli-ohms or so, where a load resistor of
even  500 ohms would be high enough to be in the region where
increasing its value further might not increase the total
 energy delivered, before recharging.

Brian W

At 07:40 PM 1/7/2004, you wrote:
> The conclusion is IMO correct.  The maximum energy delivered to the load
> increases indefinitely with the load.  However, the time it takes to
> deliver the enerygt also increases withoug bound.  Let that be a lesson to
> all: DIM BULBS BURN LONGER!
>                                 Regards,
>                                         Jack
>
> On Wed, 7 Jan 2004, Bob Sciamanda wrote:
>
> > Quantitatively,
> > W = VK = ERK/(r + R), which has no maximum, with increasing R.  The highest
> > value approached with increasing R is W = EK. ( E is the cell EMF, assumed
> > constant)
> >
> > Bob Sciamanda

> "Don't push the river, it flows by itself"
>                                 Frederick Perls


Brian Whatcott    Altus OK    Eureka!