Rechargeable AA Penlight Batteriess

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Paul W. H
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Joined: Jul 25 1999

Hi All

Is anyone aware of a Li-ion Rechargeable "AA" Penlight battery for use in Digital Cameras or anything else come to that. The Li-ion seems to be so much "stronger" than Ni-MH's

TIA

Paul W. H

Alan Roberts at work
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Joined: May 6 1999

I've not seen Lithium Ions in AA size. I use NiMh with success, excpet that when they die, they die in seconds. Like when a set decided they were empty in my Olympus C3030, they died halfway through retratcting the lens. That really had me baffled for a few seconds.

Keitht
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Joined: Jan 8 2001

This will sound like a daft question but are rechargable AA batteries supposed to be the same size as standard AAs? I was at a wedding on Saturday where somebodies digital camera batteries died. The camera supposedly takes 'normal' AAs as well. The battery cover wouldn't close over the 'normal' Duracell batteries. Anybody else experienced that.

Regards

Keith

Regards Keith

Alan Roberts at work
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Joined: May 6 1999

I've used AA cells in all sorts of kit, using ordinary alkalines, NiCads, and NiMh. All have been exactly the same size (apart from some odd NiCads that were about 0.5mm shorter so they didn't make good contact, probably Korean).

I've come across some cameras that take proprietary batteries that look like AA (same diameter and shape) but are shorter, so you get the problem you've described. Under those conditions, you're stuck with buying the special cells, but the cameras in question hadn't claimed to be using AAs.

Fortunately, the Olympus I bought last year, with it's expensive, special, Olympus Lithium batteries, takes standard AAs. So I can still use NiMh and save a lot of money. Caveat emptor.

tom hardwick
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Joined: Apr 8 1999

Ni Cad AAs are supposed to have the positive terminal about 0,5mm shorter than the terminal in dry cells so as to enable manufacturers to disable their use in certain equipment.

The very low internal resistance of NiCads vs dry cells means some delicate electronics objects to the disruption, and if equipment is designed for 6 dry cells then you'll need 7 Ni Cads to make the voltage correct.

tom.

Paul W. H
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Joined: Jul 25 1999

Hi Tom / Alan

Can you think of anyone reason why a Li-ion rechargeable "AA" battery has not been manufactured ? I am sure the demand would be there !

Paul W. H

Alan Roberts at work
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Joined: May 6 1999

Thanks Tom, I knew someone'd chip in.

I suspect that LiOn cells are too expensive to make in such small sizes as AA. And the market would be small. The market for NiCd isn't that big compared with the dry cell market. Most people, shopping, still seem to prefer to buy a 12-pack of dry cells than a few rechargeables and a charger. I often watch people in Asda, and very few go for NiCds, probably because of the extra cost. NiMh are more expensive although they're better, LiOn would go much further.

As another exmple, how many mobile phones use NiCd as the battery pack, how many are sold with NiMh, and how many with LiOn? From my own shopping around a couple of months ago (for a phone for my wife), I couldn't find any phone with anything other than NiCd, although NiMh are available as (costly) replacements.

Graeme Redwood
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Joined: Jan 26 2001

Sorry folks, it ain't gonna happen
It's all down to chemistry, alkaline/ zinc-carbon produce 1.5v per cell and NiCd/ NiMh make 1.2v but with Li-ion its 3.6v. 4 cells would result in 14.4v, so anything expecting 6v will be in for a surprize (ie your expensive delicate digital camera will be cooked ).

Paul W. H
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Joined: Jul 25 1999

Is this then a case of before you buy your next piece of "kit" look at what is powering it and the options available for powering it. I know of 4 people who have bought a "PC Package" complete with a Digital Camera and they have all stopped using the camera after a few weeks because of their appetite for Duracells, and for some reason as Alan said yesterday will not buy "Rechargeables" as an alternative. On a side issue now many people know the difference between Dry, Lead Acid, NiCad, MiMh & Li-ion, "After all a battery is a battery that comes in all shapes and sizes" !!
I looked in W.H. Smith yesterday and a pack of 4 "AA" Duracells was £4.50, Wow !!

[This message has been edited by Paul W. H (edited 19 July 2001).]

Alan Roberts at work
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Joined: May 6 1999

Paul, you raise an interesting point.

When I got my Olympus it came with a pair of Olympus Lithium batteries (not rechargeable). They should have lasted a long time but didn't because the camera was faulty. I got the camera replaced after 2 weeks and found that the new one wouldn't accept the original batteries despite my voltmeter saying that they were ok. So I put in 4 Duracells. They lasted about 30 minutes of real use. So I bought a set of NiMh and put them in instead.

Now, the Duracells are supposed to hold about 2-3Ah whereas the NiMh do about 1.2Ah (this is from faint memory, don't hold me to it). But they lasted for weeks and weeks before needing recharging. The reason has go to be the way that cells expire.

Dry cells start out as 1.5v (actually nearer 1.65v) but quickly drop to about 1.3v. As they get exhausted they steadily drop to about 0.9v before they then quickly die altogether. NiMh stay at about 1.2v until within a few % of expiry, and then they die almost instantaneously. So the camera sees a good battery right up to the end. Clearly, there is some volt drop as they age, because the camera correctly reports them as progressively emptying. But they work for a lot longer than dry cells do depite having smaller capacity.

I suspect that's why people stop using their new toys. They use the original batteries 'til they die, throw a wobbly at the cost of proper replacements and put in dry cells because they're cheap. Those don't last long so the camera gets the bad name. If only they'd go over to NiMh they'd get long usage at lower cost.

At least, that's what I reckon.

And yes, I'd forgotten that LiOn is 3.6v.

[This message has been edited by Alan Roberts at work (edited 19 July 2001).]

Alan Roberts at work
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Joined: May 6 1999

But I still use Duracells for things like torches, where the long life time and graceful death is far more important than the cost.

fisherman
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Joined: Dec 23 2000

I've just come across some lithium batteries on the 7dayshop.com site, pack of 4 for £5.95 (Plus P & P).

Described as "The worlds longest lastin batteries". Seen the same batteries in Maplins as £6.99 for pack of 2.

Looks like good value.

Also, cam across this quote on the Olympus user forum today :-

I've bought several sets of AAs from greenbatteries, as well as their chargers. Quite happy with both. Suggest you get a dual voltage (110/220) so that you don't have to get a converter if you travel.

Basically, a battery, AA, C, D is a cell and nominally 1.5 volts (not really, just nominally). The mAh rating tells you how much power it stores at that voltage - i.e., more mAh the better. 1800s are pretty high for AAs.

NiMHs are weird little buggers. The won't hold a charge very well until they have been charged/discharged a few times. When I get a new set I quickly shoot a full card of anything and then turn the camera on 'slide show' until the batteries crash, recharge and repeat until they seem to be taking a good charge. Usually about three cycles.

They also loose their charge while sitting idle. It can really bum you out when you haven't taken a picture in several days, a great opportunity comes along (you know 'Big Foot' appears at the edge of your yard) and your batteries are dead. Suggest that you buy a set of lithium AAs to leave in your camera if you aren't using it frequently - switch out to rechargeables when you go out shooting.

The lithiums are also good backups when you are out and go through all your rechargeables. When I travel I take three sets of NiMHs and a set of lithiums. 'Belt and suspender' approach.