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Old Apr 12, 2007, 11:44 AM   #11
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A point of clairification...

I thinksome peopleare mixing chemistry and sizes. The basic chemistries include Alkaline, NiCd, NiMh, Lithium, Li-Ion, and Lead Acid.

With the exception of Lead Acid, the other chemistries are available in a number of sizes.

The AA size has a metricdimensions of 14550. This means that the cell is around 14 mm in diameter, 55 mm in length, and the 0 means that it is a round cell.

The CR123A cell is a single cell (1) that is about two thirds (23) the size of an A cell (A). The 223 cell is two cells that are about two thirds the size of an A cell.

Looking at AA cells, we have:

Alkaline, NiCd, NiMh, Lithium (primary - not rechargeable), and Li-Ion (rechargeable). The Alkaline cell has a nominal voltage of 1.5 volts, but comes in at 1.6+ when new. Both the NiCd and NiMh cells have a nominal voltage of 1.2 volts, but come off the charger at 1.4+ volts. The Lithium cell has a nominal voltage of 1.5 volts, but is at around 1.7+ volts when new. The Li-Ion cell has a nominal voltage of 3.7 volts and comes off the charger at 4.2 volts.

Alkaline, NiCd, NiMh and Lithium cells are interchangeable, but if you put Li-Ion AA cells in your camera, the higher voltage of these cells will destroy the cameras electronics.

Looking at CR123A cells, we have:

Lithium (primary - not rechargeable), Li-Ion (rechargeable), and Li-Ion with a step down circuit. The Lithium cells have a nominal voltage of 3.0 volts and are at around 3.2+ volts when new. The Li-Ion cells have a nominal voltage of 3.7 volts and come off the charger at 4.2 volts. The Li-Ion cells with a step down circuit have a nominal voltage of 3.0 volts, and they come off the charger at around 3.7 volts. These cells require a special charger and normal Li-Ion cells will be damaged if they are charged on a charger designed for these cells.

The 3 volt Li-Ion cells are supposed to be interchangeable with the CR123A primary cells, but some electronic circuits end up being damaged by the high starting voltage. Most of the time it works, but sometimes it doesn't.

Li-Ion cells have a nominal voltage of 3.7 volts and come off the charger at 4.2 volts. These cells are available in a number of sizes and shapes. They fit into your cell phones, computers, and cameras. The "oxidize" from the inside, and have a shelf life that starts from the time of manufacturing. Early cells had a life of 2-3 years, but improvements have been made and now we are looking at 5-7 years. A recent test of 10 year old cells indicated some usefulness, but not much, after being stored for 5 years after being retired from use after 5 years. All of this depends greatly on use patterns. If you run the cells completely empty every time, you replace the cells sooner.

One final note. When you stack cells up, you add their voltages. The capacity remains the same as a single cell. On the other hand, if you connect cells in parallel, the voltage stays the same as a single cell, but you add the capacities of each cell together.

Back to the original question: Li-Ion vs AA

No comparison. If you put Li-Ion cells into an AA you will damage the electronics due to the differences in voltage.

Comparing Lithium vs AA, we have the Lithium cells capable of higher loads than Alkaline cells, and they hold a higher voltage than NiMh cells. NiMh cells are rechargeable, and cost less, even when you factor in the cost of the charger. NiMh cells have a self discharge rate that can be an issue for infrequent use, but the new Eneloop low self discharge rate cells have pretty much taken that concern out of the equation. I think most people end up using NiMh but keep a set of Lithium cells as a back up.

Now, if the question was which type of camera to buy, the Li-Ion powered cameras tend to be more compact and represent the latest technology. If the camera requires a lot of power to operate, the Li-Ion battery pack will weigh less. As long as you have a way to recharge the battery, you are set to go.

However, if you often find yourself with dead batteries in the middle of a backpacking trip, you may want to go for a camera that uses AA batteries. With AA powered cameras you can rob your flashlight or GPS to get that "once in a lifetime" shot.

I chose an AA powered camera. It has enough features and is not too large. The price was right, and I never worry about batteries because I carry other equipment that also use AA batteries.

My son, on the other had, wanted the most compact camera he could find and it uses Li-Ion cells. He has a back up battery for it. He finds that the very compact size allows him to carry a camera at times when he usually wouldn't. As a result, he ends up taking more pictures.

Now, if I could only teach him how to compose a shot...

Tom
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Old Apr 12, 2007, 10:46 PM   #12
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Silverfox, I will defer to anything you say, because I have read many of your posts on the net, and CPF, and do not know of anyone that knows more about about rechargable batteries, than you....

The question I've always been confused with was mAh. I thought (forgetting about voltage, and what voltage a specific camera was designed to handle) that mAh was the best indicator of how many pictures a camera can take (eg, a 2700 batt can take more pix than a 2000 batt, disregarding self-discharge).

So, my point to romphotog, was that, if 3 Li-ions propritary batteries, each with a 750 mAh rating were equivalent in SIZE to 2 NiMh AAs, each of which could be 2700 mAh, then wouldn't I rather carry the 2 AAs since I would have 5400 mAh total to work with (2700x2) vs 3 Li-ion that had only 2250 mAh (750x3)? Or.... to put it another way, a single 2700mAh AA might be able to (if a there was a camera made to operate on 1 AA) handle more pix than three 750 mAh Li-ions and also be half the SIZE to carry?

Amazingtailand, I've done exact that with my mobile phones, previous cameras, etc... eg, have one extra Li-ion that I rotate in when the primary dies..... I don't like rotating Li-ions nearly as much as AA NiMh for the reasons I posted in my March 12th reply above. As you will also see from that post above, that I've adopted an all AA mentality for the exactly the same reasons that Silverfox has in his 3rd to last paragraph.

The bottom line, for me, is that after I've purchased a camera, or any other portable electrical gadget for that matter, and know exactly what that device is capable of, then the only other variable/disappointment I constantly have come across is battery life/performance/failure. Since converting over to AAs now, I no longer worry about it, because I have so many back-up alternatives.

For example:
1) I carry 1 set of charged NiMh (same as you carry 1 Li-ion back-up). But for me, this 1 set of AAs backs-up multiple AA devices. You, however, would need to carry a different Li-ion back-up for each device.

2) I can throw a set of lithium AAs (20 yr shelf life, BTW) in my bag if I think my primary back-ups are may not be enough (you don't have this option). And lithium AAs will last longer than 2700 NiMhs.

3) If my primary NiMhs back-ups are not enough, and my lithium AAs back-ups are not enough, or I forget to pack them, I can easily buy alkalines in a store. Yes, they don't last long... but they'll last long enough (you don't have this option)

4) If my primary NiMhs back-ups are not enough, AND my lithium AA back-ups are not enough, AND I can not get to an open store, then I can always cannibalize off another one of my AA devices (once again, you do not have this option).

I do agree however, with limiting my choices in cameras.... I however don't quite see it that way because the most limiting/worrisome thing I've ever experienced in a digicam/cellphone/MP3 player, etc. has been always been the battery.... with AAs I no longer worry about batteries (points 1-4 above).
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Old Apr 13, 2007, 12:39 PM   #13
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Hello Reppans,

To compare different chemistries, we have to look at power. Watt Hours measures power available from a cell.

Let's look at the 2700 mAh NiMh cell. It has a nominal voltage of 1.2 volts. Multiplying the two together we come up with around 3.24 Watt Hours. Since Li-Ion chemistry runs at a nominal voltage of 3.7 volts, we take the 3.24 Watt Hours and divide it by 3.7 to come up with around 876 mAh. That means that the power available in a NiMh 2700 mAh cell is equal to that of a Li-Ion 876 mAh cell.

When we go to multiple cells, it depends on how the cells are arranged as to what you end up with voltage and capacity.

My camera takes 2 AA cells in series. The 2 AA cells provide 2.4 volts and if I am using 2700 mAh cells, 2700 mAh. This works out to 6.48 Watt Hours. Comparing this with a single Li-Ion cell, to get the same power you would need a cell with a capacity of around 1750 mAh.

Tom
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Old Apr 13, 2007, 10:50 PM   #14
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Thanks Silverfox... that clears it up. Makes perfect sense as I do know that Li-ions will always be more efficient than NiMh's size for size or pound for pound.

Great explanation!
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Old Apr 21, 2007, 3:38 PM   #15
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I used to have strong convictions on this topic. I've had plenty of problems with NiMH and LiIon.

My good LiIon cells have performed very well. I have some Canon brand LiIons that are a few years old and still deliver great performance. A couple of years ago, I purchased an off brand LiIon for the same camera and it only lasted a few months before it would no longer hold a charge.

I've had loads of problems with NiMH cells too. I believe most of them stem from the poor quality chargers I've used in the past but I've had bad cells too. With a La Crosse BC-900 and either Energizer 2500s (some made by Sanyo and some I believe are not) or Eneloop cells, I've had outstanding performance.

It seems to me, with decent equipment, either LiIon or NiMH will deliver excellent performance. I would not stay away from a camera because of battery technology.
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Old Apr 22, 2007, 10:37 PM   #16
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There is probably an easier way to work it out for the average person....

Three NiMH AA cells in series = 1.2V x 3 = 3.6V

This is close to the voltage of a Li Ion battery. (3.7V)

If you want to compare the two, and your NiMH batteries are 2700mAH and you use two of them, then an equivalent Li Ion batterywould beapprox: 2700 x 2/3= 1800mAH




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Old May 24, 2007, 11:45 AM   #17
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SilverFoxCPF wrote:
Quote:
I chose an AA powered camera. It has enough features and is not too large. The price was right, and I never worry about batteries because I carry other equipment that also use AA batteries.
Wonderful to encounter a *real* battery person. I'm a retired, non-battery electrochemist myself, and once had to write a general purpose 'batteries' report.

I have just fallen right into several of the issues you raise, when I purchased my generally excellent new Kodak Z712is digicam. I, and my friends in my excellent local camera shop, fell into the trap of assuming that the spaces for 2xAA batteries in the camera meant it would use Ni-MH AAs, as did the very similar Z610 and Z612. I was wrong, as careful reading of the relevant manuals reveals. A pair of fully-charged 2500mAh Ni-MHs will do about 8 or 10 shots, before the low batt warning appears, after which if you switch off, it'll switch on & then shut down straight away. I think this happens at a total voltage of about 2.6, which one reaches pretty rapidly with 2x AA Ni-MH.

Entertainingly, the Z712is ships with a disposable CR3V2 Li battery alone, and not the Li-ion rechargeable and charger with whichpredecessor (without image stabilisation), the Z710 arrived.

So the headline price, unless you're happy to use disposables indefinitely, doesn't include battery & charger. This will go down very badly in the UK market, where everyone is rapidly becoming eco-conscious, as well as cost-conscious.

Good Luck,

Alan T
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Old May 25, 2007, 1:10 AM   #18
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Alan T wrote:
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SilverFoxCPF wrote: Entertainingly, the Z712is ships with a disposable CR3V2 Li battery alone, and not the Li-ion rechargeable and charger with whichpredecessor (without image stabilisation), the Z710 arrived.

So the headline price, unless you're happy to use disposables indefinitely, doesn't include battery & charger. This will go down very badly in the UK market, where everyone is rapidly becoming eco-conscious, as well as cost-conscious.

Good Luck,

Alan T
You might want to go to rechargeable lithium ion batteries. There are some after-market replacements for the Kodak KLIC-8000 which the Z712 operates on.

style="BACKGROUND-COLOR: #000000"One option is www.bestbatt.com where you can get both the batteries and charger. I use their KLIC-8000 myself and am very satisfied with the company's service and products.
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Old May 25, 2007, 1:42 AM   #19
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bayani wrote:
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You might want to go to rechargeable lithium ion batteries. There are some after-market replacements for the Kodak KLIC-8000
Yes, thanks.My friendly local (and very cheap) camera shopalready has the batteries,and arriving shortly I'll have a reasonably-priced Uniross charger. When I discovered the "No Ni-MH" issue, they traced & ordered five in a hurry, realising that anyone who purchased a Z712 might well want a rechargeable and a charger. I'll carry a disposable CR3V2 as a backup.

On holiday in the Isle of Man at Easter in our camper van (RV), I'd already fallen into the Li-ion charger trap by remembering to take my 12VDC to 240VAC inverter, and my Casio Z750's charging/downloading cradle power supply, but forgetting to take the cradle itself, which lives alongside the computer at home. I had to go out and buy (for 35ukpounds!) a spare 3rd-party Li-ion rechargeable for the Casio, which a photographic store charged up for me overnight, using a slightly later model Casio and its cradle.

So this Li-ion vs AA issue has cost me a lot of money, in spite of the fact that I own dozens of well-maintained AA Ni-MH cells. Now I have a spare Li-ion rechargeable for the Casio, which will get little use -only when I need a shirt breast pocket camera. I've moved on to the much better Kodak for general use, and sadly Li-ion rechargeable lifetime isn't brilliant even if you don't use them (as noted somewhere above in this thread, and as I know from camcorder experience).

Hi, ho.

Alan T




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Old Aug 4, 2007, 4:30 AM   #20
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Hi, I have a Kodak z612 camera and have had difficulty obtaining a replacement Klic 8000 battery for it (Kodak don't even have stock just now). I would like to have the choice of using normal Nimh batteries but they don't fit the camera as supplied.Do you know of anywhere I can obtain and adaptor that will let me use Nimh batteries as a a back up?



thanks....
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