That's true. I don't know if this applies to Nimh batteries, but nicads can be "trained' to discharge faster. When my son and I raced electric radio control cars, I would train the nicads by discharging them on a resistor pack with just 1/2 an ohm resistance. I had some 1800 mAh C batteries, wired into packs of six, that initially discharged in about eight minutes. After a few cycles of training, they would discharge in four minutes and a few seconds, delivering an almost constant 1.7 volts per cell for the entire time. We ran four minute races, so this was ideal. Of course the batteries would be smoking hot at the end of a discharge cycle. On the resistor pack I cooled them with a computer fan. In the car, the airflow cooled them somewhat. They would usually maintain peak performance for at least twenty or thirty cycles. On Nov 11, 2006, at 12:36 PM, Godfrey DiGiorgi wrote:
> As Adam said... > > A 1500mAh battery of a particular type might provide power for small > percentage less time than a 1750mAh battery, but with respect to form > factor and voltage they will be identical. > > Sometimes the mAh ratings aren't particularly accurate. For instance, > I have a Sony and a CTA battery for the R1, the Sony is rated 1100mAh > and the CTA is rated 1450mAh. But the Sony lasts just as long as the > CTA, so either the Sony rating is pessimistic or the CTA is > optimistic. For the A2, I have both KM and Impact batteries and the > ratings at least work as expected: the KM is 1500mah and the Impact > is 1800mAh (I think), the Impact definitely lasts longer on a charge > in the A2. > > Godfrey > > On Nov 11, 2006, at 9:11 AM, Adam Maas wrote: > >> mAh is a measure of capacity, the more you have, the longer the >> battery >> will last in a given application. >> >> 2500mAh is likely not possible in that form factor, to make a 7.4v >> 2500mAh battery would require a physically larger battery. >> >>> Does it matter much if one uses a 1500, 1700, or 1750 mah >>> battery? What do >>> those numbers actually mean? Could one use a 2500 mah battery >>> (assuming >>> one was available)? >>> >>> What I'm getting at, if I'm not clear, is that I heard that >>> batteries for >>> the Pentax need to be within some certain range of volts or amps - >>> some >>> power range, I guess - in order to properly work in the camera. >>> Are the >>> figures you gave capacity, which, I suppose, means how long the >>> battery >>> might last, as opposed to the actual power of the batteries. >>> >>> I, for one, could certainly benefit from a better understanding of >>> batteries. Perhaps others could as well. >>> >>>> <http://forums.dpreview.com/forums/read.asp? >>>> forum=1036&message=20723942> >>>> or >>>> http://tinyurl.com/y4k8gv > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
