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01-04-2007, 12:45 PM   #16
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just been back and had the look at the link above i posted.. they quite clearly state 3.7 volts per battery which means 7.4 volts per two packs in series.. the cameras they say they work with are all pretty much designed to work off AA 1.5 volt cells.. either three volts for two AA cells the kodak dx3600 for example.. i have one.. the toshiba four AA cells.. i have one.. an olympus E20 four AA cells my son has one..

so they are quite clearly saying their 3.7 volt rated rechargeable lithium cells are okay to replace 1.5 vol AA cells.. or be used in cameras designed for AA cells

now assuming a whole bunch of people have bought them.. and the same people are useing them in their AA powered cameras..

and so far i havnt heard of whole bunch of exploding cameras they must work okay..

is someone somewhere inventing problems that dont exist..????

i dont really need a pentax user to say they are okay.. there must be oodles of folks out there useing the damn things in their designed for AA battery powered cameras..

trog

01-04-2007, 01:18 PM   #17
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anyways to cut a long story short i have just plugged the 7.4 volt twin cell external lithium pack i have into my k100.. the camera hasnt exploded or done anything unusual and works okay..

i also cant detect the slightest difference in autofocus speeds either.. i switched back and forth a few times.. focused on the same object in poor light.. plug in plug out.. four AA metal hydrides 5 volts or two 3.7 lithiums 7.4 volts i cant tell the difference..

so i now doubt the claimed improvemenst i have read about and the whole exercise becomes somewhat academic..

i think the entire camera is regulated down to about 4 volts including focus motor and thats it..

trog
01-04-2007, 01:56 PM   #18
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Chedoy. Could you let us know how the eneloops perform. I am planning on gettiing those as well. I have been using Sanyo 2500 Mah i got from costco a while ago, so far i have full battery after about 100 shots, most with flash and lots of viewing with the LCD screen. I was a little worried when the first set of NIMh batteries i put in lasted about 25 shots - they were older and lower power. If the Sanyo's give me 250 shots of use I am happy enough with that. so far it looks like they will exceed that number. I would use the eneloops as back up fully charged batteries in the bag.
01-04-2007, 01:57 PM   #19
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I think you MAY notice the improvement ovre time as the batteries run down... At least when I compared CRV3s to NiMH they were both pretty much on par at the begining but over time the camera slowed a little as the NiMH wore out (voltage dropped?)... Whereas nothing really changed over time with the CRV3s which I think hold their voltage better, and just drop of fast and die at the end of their life. I noticed it most with MACRO lenses as they have a huge amount of travel in them...

That was with the ist DS and D though with the K100d I never tried anything other than CRV3 so can't say if it made a difference..

01-04-2007, 02:59 PM   #20
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metal hydrides just like nickel cadmiums dont suffer gradual voltage drop off.. a bit of a negative with battery life indicators..

they have an initial slighly higher than normal voltage when fresh off charge.. this drops off very quickly within minutes of the first use..

then they maintain the normal 1.2 volts per cell right to the last second then instantly die on u pretty much without warning.. which is why battery life indicators which read battery voltages are not much use with such batteries.. u never know when they are about to go flat..

how CRV3s behave i dont know cos i have never used them but i have used the other type rechargeable for many years and in many applications.. they dont suffer gradual voltage drop off.. i play with RC controled airplanes.. batteries going flat at the wrong time can be a problem.. he he

soo that theory is out.. it is possible to have one dud cell in a pack that goes flat before the others creating the impression of voltage drop off.. but thats down to the poor cell.. four good ones wont do it..

my test was only quick i give u that.. but i did use my 18 x 200 lens which isnt the fastest focusing lens on the planet and the indoor light (dim tungsten bulbs) was poor.. i did about a dozen swop overs.. easy to do when all u have to do is pull a plug out..

the 4.8 volt 2100 mah metal hydrides were charged a couple of days ago the 2000 mah lithium pack last night.. it read 7.4 volts prior to me connecting it..

if there was any significant difference i am sure i would have noticed it.. we are talking over two volts difference.. once u remove the voltage drop off theory i cant see much else left..

i think the pentax world is full of folks useing duff metal hydride cells to be honest and its getting em a bad name..

i have dozens and did have to throw some away before i sorted out some good four cell bunches.. all it takes is the one "not so good" cell in the pack of four and the performance is useless..

i have also found from experience that its not wise to buy the highest capacity metal hydrides that are available.. they keep sqeezing more and more into them but i think the ones they havnt sqeezed so much into are much more reliable.. i have some three year old kodak 1800mah ones that still work well..

the ones i had to throw away were my last purchased 2500 mah ones.. the entire pack of twelve ended up in the bin..

the other promlem is the charger.. an awfull lot of them dont work very well.. they switch off long before the batteies are in fact fully charged..

the only really reliable one are the good old charge at 10% capacity and leave overnight jobs.. most of the auto fast charge and switch off things are rubbish..

still its all grist for the mill.. as they say.. he he he

trog
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