Do you have a k-r with an AA adapter?

If you do, could you please, do me a huge favour and check the voltage you get with the four batteries in the adapter with a volt meter if you have one of those as well.

I'd be extremely grateful,

Many thanks
Charlotte

I don't have the adaptor but the most you should have is between 5 volts for 4x NiCd, and 6.6 volts for 4x NiZn

Charlotte - I have a genuine Pentax adapter, but no voltmeter. Having said that, the adapter is designed to connect 4 batteries in a serial pattern. Since AA's are rated at 1.5 volts per battery, all 4 should provide 6 volts.

Are you encountering a specific problem then, hence your question?

you cannot just add up 1.5 x 4
different battery types have different characteristics and voltages...

nicad and alkaline and lithium and nmhi are all gonna be different...

Hi Charlotte. Just checked mine. It's not a digital meter so I can't be absolutely accurate, but it's just shy of 4.5 volts. This is using 4 X Sanyo 1900 mAh Eneloop which were charged about 5 months ago, but haven't been used since charging (if that makes any difference )

Don - it's the basic principle of electrics. AA Batteries are manufactured to produce an average voltage (when fresh) of 1.5V. The different chemical types you mentioned may discharge their stored capacity at differing rates, hence the reason why high-capacity devices such as flashguns should not be powered by standard batteries - the capacitors inside flashguns cause the chemicals inside to literally boil, and results in leakage. The batteries you mentioned have a less volatile reaction, thus they are recommended for use in such devices...

Bottom line - AA batteries are designed to hold a voltage capacity of 1.5 volts (give or take a few millivolts).

link (comparison) shows that you are correct in what you say, but it also backs up my point.

If you are talking to someone with a problem and asking voltage readings then a 32% difference in the voltage between battery types is significant, I would think!

Thanks all,

Mine are showing about 4.5 - 'tis all very confusing. I wasn't sure whether the batteries connected in a serial pattern or not.

What's confusing me is that the proper pentax battery that came with the camera shows 8.2 fully charged, and presumably even if you have the NiZn you aren't going to reach the 8.2 of the original.

I'm just doing some tests to get to the bottom of my mirror flipping problem and wanted to check that my AA batteries were giving the correct reading on my volt meter.

I shall then check the batteries when it starts flipping to see if it is something to do with the battery voltage. When it starts the flipping and I take the lens off of the camera and press the shutter release it works fine so I'm thinking that at that stage perhaps the battery hasn't enough power to deal with the lens as well as the shutter.

I think perhaps I'm clutching at straws, but nothing ventured nothing gained so they say. (who ever they are)

Thanks again,
Charlotte

AA Rechargeables are not rated at 1.5 volts, they are 1.2 volts. This will be when at full capacity, so I would expect that 4 of these would not yield any more than a maximum of 4.8 volts. More usually 4.5 would be a realistic output.

Regards
David

I would take your readings with a pinch of salt, according to Pentax the original battery is only rated at 7.4 volts.

I expect there is a power supply converter in the camera, thats why in the menu system you have to select battery type or auto.

Jeff

that .25 volt difference times 4 batteries adds up though... as I said.. it isn't as simple as 1.5x4... 1.2 (or 1.25)x4 is a big difference... if the equipment is sensitive... so the OP's question is to broad to give a correct answer to.
and the voltage is irrelevant.... the battery type of course matters most here.. with nimh being the best performance/cost value available... and there being multiple capacities available amongst the brands and models... a simple voltage test means nothing here..

Charlotte,

you could do with finding out what the cut-off voltage is inside the camera, below which it won't operate all the functions properly. Once your batteries combined voltage falls below this figure then you will have problems occurring. If the manufacturers battery is rated at 7.4v then it may be that the minimum voltage required to operate the camera properly is closer to 5v than 4.5v. AA NimH rechargeables rated at 1.2v nominally, usually give about 1.25v-1.3v when fully charged. Depending on the quality of the internal cells used the initial voltage might drop more suddenly with one make than with another meaning that the critical 'cut-off' point is reached sooner. If you do find that the batteries might be your problem then it could be that one or more of the batteries is not holding its charge as well as the others. This can be critically important if your minimum operating voltage is already close to the total voltage available when the batteries are fully charged.

If this is the case then you might need to experiment with different makes of battery or buy some new ones anyway if your existing batteries are well used. From experience I can highly recommend Ansmann Professional 2850mAh AA NiMh. Very good design, well matched internal cells, robust chemistry designed for rapid charging and high discharge rates and come with a 2 year warranty against malfunctions caused by faulty manufacture. A pack of 4 in UK costs about £13- £14. Other people might be able to recommend other such batteries.

Something else you could try first with the batteries is to see if you could borrow
a set of 4 Lithium AAs of someone who has recently put them in their camera or other appliance. These batteries leave the factory at between 1.65v - 1.7v each and maintain this voltage for most of their life. This type of battery will get you much closer to the original spec of 7.4v than anything else in disposable/rechargeable batteries. If the camera works fine with these then that is your problem identified. If it still doesn't work properly then It is likely to be something other than the batteries causing it. These batteries cost typically £6 -£8
for 4 and are disposable one use only...but they should give you about 600-800 shots
per set and are virtually impervious to very hot or cold climatic conditions which affect most other types of battery. Hope this helps.

Here a link to wikipedia link giving info on aa batteries and their voltage.

Jeff

Oops!

I should have checked out the previous link.

Well it was getting late.

Jeff