Battery - steady volt? how?

Thread Starter


Joined Aug 14, 2005
Nernst equation says that ? = ??+(RT/nZ)ln[products]/[reactants] suggesting that the potential difference between the terminals of the battery is dependent on the concentration of reactants and products. Since the concentration of the reactants and products is continuously changing as the reaction proceeds to produce current, how can a battery maintain, in theory, a constant voltage? The battery will probably maintain a constant voltage for an infinitesimal time at the very beginning of the reaction where the concentration of the reactants and products haven't changed their concentration appreciably; but what about the rest of the time?

Thanks in advance if anyone could throw some insight.


Joined May 16, 2005
The quick route to the long answer is found in Pebe's link, "Part One," under Discharging - Calculating Battery Run Time.

The short answer is that batteries do not provide constant voltage.