Re: [Phys-l] Energy balance in charging battery

[Bernard Cleyet <bernardcleyet@redshift.com>]

My ISP is acting up again; second sumission -- claims unable to send.

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"Note that r may change a bit as the battery charges and discharges...."


Quite a lot in the case of Pb-acid cells.  This, I suppose, is because 
the concentration of electrolyte ions decreases (they "go into" the Pb 
to make PbxSO4)

Ni-Cd/MH cells are unusual as their internal R changes little 'till they 
are  about exhausted.

bc obviously not a chemist.


Shapiro, Mark wrote:

> The r is the "effective" internal resistance of the battery, so the (I^2)r losses end up as heat.  The IE part goes into chemical energy to charge the battery, but you don't get all this energy back out as electrical energy because of the (i^2)r' losses within the battery as it discharges.  Note that r may change a bit as the battery charges and discharges....
>
> Mark
>
>  
cut