Aren't rechargeables for high current applications?

I've seen some of the cheap counterfeit Duracells. Holding them in your hand, they're noticeably lighter than real Duracells, and I'm sure that they aren't really even alkaline AA cells. I think that most of the people that buy (or bought) them were for use in portable CD players, where the very low current requirement allows them to fool naive purchasers.

"Rich Gripes"

The same cameras only extracted a fraction of the energy capacity of an Alkaline cell too.

Wot a liar.

The *initial* internal resistance of an Energizer or Duracell AA alkaline is about 5 times higher than a NiCd.

After some period of use, the ratio goes out to 10 to 30 times higher.

Huge difference.

..... Phil

Are you talking about a "switch" or do you know what's going on inside of the camera?

Same question as above. Looks like you are talking about what's going on inside of the camera, but I doubt it.

And what happens? Does the camera stopped working?

You are looking at an incorrectly adjusted voltage level indicator (when you use rechargeables but don't correctly set the camera). That is meant for you the user, it should not affect operation of the camera.

John Devereux wrote in news: snipped-for-privacy@cordelia.devereux.me.uk:

packaging and selling carbon-zinc cells as alkalines is illegal.

This was my first thought as well. It is not easy to find a good reliable charger. I went through a couple and they all had some kind of deficiency. My last one from ELV elektronik (Germany) was not cheap, looks really sophisticated yet after a few uses I found it won't even detect one of the almost brand-new NiMh and I know that accu is good. Many of the wall-warts are crap, too.

Previous charger was also supposed to be good, even supported cycling. Yet it would drive some accus into severe overheating, obviously failing to detect the accu has been charged.

The only way to know for sure is to design one on your own. But who has time.

Cameras almost always implement battery "switches" via menu options.

Same answer as above.

If well designed it *will* affect the operation of the camera. Some old cameras probably had "dumb" battery warning indicators, relying only on observant users to power off the camera and swap batteries. But that was then, and now it's different for most cameras. Battery voltages fluctuate with usage, dipping more when zooming the lens, focusing, writing to memory cards and especially when recharging the flash's capacitors. Cameras can perform many different types of operations when the batteries are fairly close to the minimum operating voltage (a range, not really a point, due to component tolerances). This is the point where a well designed camera will shut down, because at this point if one more picture is taken, there may not be enough energy left in the batteries to complete saving the picture to the memory card, and this could trash the card, even though many other operations could still be safely performed, such as changing menu options, changing shutter speeds and f/stops, even reviewing previously taken images.

Other devices also intelligently shut down at different voltages. Many PDAs not only let you specify the battery type used, they also have utilities that let the user redefine the voltage points where battery warnings are given, as well as what voltage level initiates the shutdown of the PDA. I'll leave this as an exercise for the authors of the CHDK hack to implement - assuming of course that they haven't already done so. :)

You have called me clueless several times in another thread, Jack, but my question here is going over your head. Yes of course a camera copes with lower voltages, but that's not the question. This is the question, in the other words... When you use a switch to tell the camera whether it's running off of disposables or rechargeables, does the camera do more than just properly display the remaining power?

That doesn't answer the straightforward question seven lines above, Jack, because you don't know what I'm talking about.

"John Dope Head " snipped-for-privacy@radagast.org (Dave Platt)

" You are looking at an incorrectly adjusted voltage level indicator (when you use rechargeables but don't correctly set the camera)."

Dave only spoke of a low battery warning light.

...... Phil

"John Dope Head "

- f*****ad.

..... Phil

You've just confirmed your cluelessness (or worse) to the entire newsgroup. Your questions *were* answered, but the answers didn't register. Even if a mechanical/electrical switch is used instead of a menu option, the camera uses the setting to do more show an approximation of the remaining battery life.

Interesting. If you're not clueless, you're not like our resident pseudo-omniscient sock puppet trolls, you're playing a stupid troll, aka one that doesn't know Jack, Jack. Or maybe reasoning is just beyond your abilities.

It's a logistics issue. If I know I'm going to an event where I'll need my NiMH's, then I charge them up a day or so in advance. I usually bring 4 sets (16 AAs) to use with two flash guns.

However, if something comes up at the last minute then it may mean my NiMH's have been sitting around unused for weeks, so they are partially discharged. Because of that, I usually also carry 8 - 16 alkalines as backup.

Your subject line is misleading. Hi current recharge of camera flashes is not related to the slow discharge issue.

I really wish they could increase the NiMH voltage to 1.5 - 1.6v. Then my flashes would recycle a lot quicker. I get a typical 2 - 3 seconds, but for longer range or smaller apertures the flash cap might be completely drained and then it can take 7 seconds to recharge the cap.

You're blaming the batteries on a poor camera design.

Next!

It's not NiMH's lower voltage (vs. other AA types) that's responsible for your flash's recharge times of up to 7 seconds. High powered shoe mounted flashes using the highest voltage AA cells (lithium, over 1.6v) take longer to recharge fully depleted flash capacitors than any other types, at least in Nikon's speedlights, up to three times longer than when NiMH AA cells are used.

Using 4 RayOVac Hybrids that were last charged almost 2 months ago and had been used several times since then (including many family shots during Thanksgiving) I tested the SB-800 with the lens set to f/22 to see how many full power flashes* could be taken in about one minute. I got 17 shots off in 58 seconds, or 3.41 seconds/flash. The SB-800's delay is effectively zero seconds for my typical "less than full power" flashes. If I try shooting a dozen shots *very* quickly, nearly as quickly as the shutter can be pressed, the speedlight's ready light only goes out after the 7th or 8th shot.

Nikon's manual rates the SB-800 for 4 sec./flash, but their rating was for use with standard NiMH AA cells and I was using RayOVac's low self-discharge NiMH cells, which may be why they recharged more quickly. I can't be sure, though, since Nikon's manuals say that the SB-900 takes the same amount of time to recharge using either

• The warning indicator flashed after every shot, indicating maximum output and possible underexposure, and didn't try to shoot again until the SB-800 indicated that recharging had ended.

...

This would be a good time for a naïve reader to do an author history. Or just look at a few of Alice's posts to this group.

Says the group idiot.

In fact they do display an estimation, Alice, and that display is based on the user selected type of battery given the current voltage level.

And how is the camera treating that low voltage differently when the user selects rechargeable instead of alkaline?

That is the question.

I'd consider it, Alice, but your head is way over there in Australia.

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Oh my.

Like what, Jack? How does the camera use a rechargeable's low voltage differently than it uses an alkaline's low voltage?

It's a simple question, Jack. When you have the camera set for alkalines but you are using rechargeables, when it prematurely shows low voltage, does the camera switch off mistakenly because you have incorrectly set the battery type? How does the battery type swhich effect anything besides the user interface?

If one group designed cameras for all manufacturers, this generic question might be easily answered unless the designers were perverse. As this is not the case you'll have to do your own testing or rely on the kindness of strangers to do your testing for you, realizing that the answer is not likely to be consistent even within a single manufacturer's product line. Unless there's some other solution, I don't think you'll get your answers soon even though the test method should be fairly simple. As many inexpensive battery chargers can automatically detect the difference between alkalines and rechargeable batteries, cameras that require a user to select the battery-type with a switch or menu setting may be indirectly telling you that the manufacturer wasn't generous in allocating funds to develop the camera's firmware, and the designers may have been forced to cut corners in other areas as well.

The reason behind that is that the *voltage regulation* of different AA cell type varies significantly as they approach the critical minimum voltage for the camera. NiMH types have good regulation ( ie low internal resistance) even when near the fully discharged condition.

The same is not true of alkalines or lithium primary cells - so the camera gives the warning at a slightly higher voltage with them.

The issue is simply that the camera has no ability to charge cells.

..... Phil

Way, as they say. Not to charge cells but to determine cell type. The above is merely one method and there are others. Comparing cell voltages under very light and moderate loads is another, one which most people can do with nearly 100% accuracy using very simple, inexpensive equipment, and their equivalents are already present within cameras capable of displaying low battery warning indicators. I know that I can. Can't you?

In other words, Jack, you don't know.

Sure it is, Jack. The answer is No.

That's bullshit, Jack. Even the MH-C9000 sometimes mistakes rechargeables for alkalines.

Develop the cameras firmware? You're full of it, Jack.

Name a camera that automatically detects whether you are using disposables or rechargeables.