But the camera doenst say anything under 1.2V is "dead", the nominal rated voltage of nimh is 1.2V. Nimh would not be very useful in a *istDS if under 1.2 was dead and thats not the case from all the nimh I have used in mine. off brand and energizers are giving me long life in days and shots though I dont have the absolute numbers ( I havent recorded them), but based on discharge curves both under load and self discharge, if the istDS was crapping out at under 4.8V It would not be giving me the useful life per charge.
Regarding trickle charge, I already noted its not recommended and that pulse charge is the best way to keep topped off. But I can tell you of all my sets used for 2 years now, I am not seeing any degradation of these cells yet, I trickle with 50Ma. JC O'Connell hifis...@gate.net -----Original Message----- From: pdml-boun...@pdml.net [mailto:pdml-boun...@pdml.net] On Behalf Of Cory Papenfuss Sent: Wednesday, January 07, 2009 8:47 AM To: Pentax-Discuss Mail List Subject: RE: *ist DS storage question I've had some experience with NiMH and a good battery charger with my -DS.... although no Eneloops (yet). I've had two different batches of cheap, no-name batt (Powerizer?), and a couple sets of Energizer. I've got a LaCross BC-900 charger so I can accurately see how they perform and charge/discharge them correctly. Bottom line is that the camera (at least the -DS) is *VERY* dependent on battery voltage. It will crap out and refuse to operate once the loaded voltage goes too low... where "too low" is NOT the 1.0Vpc that is typically used to measure cell capacity, and "loaded" is the relatively large current the electronics draw when the camera is turned on. Look at the second plot in the link you sent. If the camera says any battery less than 1.2V is "dead," then no-name will have 800mAH and Eneloop 1400mAH. In fact, if the threshold is anything more than 1.1V, the higher (under load) voltage of the Eneloops will be superior to the no-name. Most electric devices crap out WAY before the minimum threshold voltage of a "dead" NiMH cell... the only time you get the rated capacity is under testing on the bench, or using devices that don't shut off (flashlights, etc). Oh, and the continual trickle charge is not necessarily the best way to keep batteries in good health. It can grow metalized "whiskers" within the cell and shows up as voltage depression... effectively reduced capacity. -Cory On Tue, 6 Jan 2009, JC OConnell wrote: > never mind, I looked it up myself, > as you can see, even sanyo's own > "regular" nimh batteries have "far superior" > capacity on a full charge than their > own eneloopes: > > http://www.eneloop.info/home/performance-details/capacity.html > > So what does this mean, well if you use your > batteries within a couple months of charging > the eneloops will run out of energy quicker > than regular nimh batteries. > > the only advantage of using eneloops is if > you charge and then dont use for two months > or more. By then the self discharge of the > regular nimh will have equalized to the the lower > capacity of the eneloops have in the first > place when fully charged. > > So, unless you actully wait 2 months to use the > eneloops after charging, they are inferior, > not superior to regular nimh for what a battery > does which is store ususable energy. > > JC O'Connell > hifis...@gate.net > > > > -----Original Message----- > From: pdml-boun...@pdml.net [mailto:pdml-boun...@pdml.net] On Behalf > Of JC OConnell > Sent: Tuesday, January 06, 2009 8:45 PM > To: 'Pentax-Discuss Mail List' > Subject: RE: *ist DS storage question > > > yup, far superior if you value charging but not using your batteries > for months later. BTW, do these eneloops have as much capacity in mAH > as other nimh batteries or not????? > > JC O'Connell > hifis...@gate.net > > > > -----Original Message----- > From: pdml-boun...@pdml.net [mailto:pdml-boun...@pdml.net] On Behalf > Of Bruce Walker > Sent: Tuesday, January 06, 2009 6:50 PM > To: Pentax-Discuss Mail List > Subject: Re: *ist DS storage question > > > Brian Walters wrote: >> Re rechargeable batteries. It's been said before here but worth >> repeating that Sanyo Eneloops are far superior to most other >> rechargeables. > > Uh, oh. Fire in the hole! > > :-) > > -bmw > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > -- ************************************************************************ * * Cory Papenfuss, Ph.D. Electrical Engineering, PPSEL-IA * * Research Associate, Vibrations and Acoustics Laboratory * * Mechanical Engineering * * Virginia Polytechnic Institute and State University * ************************************************************************ * -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
