> For non-camera use, I'd make sure I charge them just before use, or if > they've been sitting around awhile. They also don't work well in flash > units, because of the slightly lower voltage than equivalent AA > batteries.
Not true at all. The voltage going into a flash unit is pretty meaningless, as that will be stepped up by the triacs and such inside the strobe. They tend to charge faster, MUCH faster than alkelines. Why? good question, simple answer. Internal resistance. An alkaline battery at 1/4 discharged will already have close to 1 ohm of internal resistance. A NimH cell will top out at 1.2 ohms, and maintain less than .5ohm resistance down to about 80% discharged. The drop in voltage is negated by the much higher current a NimH cell will put out. Not buying me? Check out the manaul for the old Vivitar 283. (or any modern strobe, you usually find the same thing) The manual states that the recharge time is 11 seconds for Alkaline, but only 8 seconds for Nicad. Nicad and NimH have similar voltage curves, and therfore, similar voltages and voltage drop. So, with most strobes, you will get much better performance from Nicad or NimH or the new NioX stuff compared with alkelines. This is because of voltage drop. You may have available 1.5 volts, but say on a 4 cell strobe, y ou now have 4ohms of internal resistance (at best, near 80% discharge an alkeline will be as high as 4 ohms per cell), which means the voltage will drop big time! However, with a Nimh or Nicad, your only looking at 2ohms of internal resistance, so half the voltage drop! Charging a strobe has nothing to do with volts, its all about the amps. > -Mat > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- Ben 'Polyhead' Smith KE7GAL -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
