I am looking for the average capacities of common battery sizes such as AA, AAA, C, D, 9V, etc.
I've done a quick Google search and not found what I need. In the past I have thought about setting up a test set to measure battery performance. I thought it would be interesting to do some independent tests of different brands of batteries and then publish this info on a web site.
Due to the current state of battery development and the hype and advertising bull, I now think there might be a business opportunity in setting up a testing protocol, equipment and developing a web site devoted to batteries. Anybody want to comment?
There is probably at least one a standard test protocol already. There may be an industry standard, and it seems likely that large buyers -- especially military -- have performance standards and acceptance testing procedures. Many different types come in the same packages, and slight changes in chemistry can suit a cell either to bursts of high current or to long slow discharges, but not both. A general testing spec can become complex.
Writing to the makers of some heavily advertised cells asking for technical information to back up their claims, and for how you could verify them yourself, might bring you the information you want.
On Sat, 30 Dec 2006 18:51:34 +0000, Chris Eilbeck proclaimed to the world:
Yes. Thanks.
I have a flashlight fetish. I do, or did, a lot of work on stuff not very well lit and carried a pocket flashlight with me. I also make maps of caves, so used headlight a lot. When bright white LEDs were first manufactured, I converted the best headlight gear I could find to LED. This was an instant hit with other cavers and I found myself beset with requests for similar conversions so I started a little business that my daughter could work at making conversion kits for different lights. This all just reinforced my fetish. Nowadays I wear a 1 watt LED light that uses three AAA batteries. These get sucked dry after a day or two, depending on how well I remember to cut the light off after done. This means I am spending 30 to 40 bucks a month on batteries just for the headlight. I was looking to see how much of a capacity increase AAs have over AAA. I was thinking of building a new headlight using AA batteries or perhaps a single C. If I go with a non electronic design I must use three cells to get the voltage high enough and then limit the current by using a dropping resistor in series with the LED. This is how the light I use now works.
I change batteries at around 1.2 volts, so using the graphs from the duracell site this is reached at just under one hour with a .25 watt load for the AAA and just over four hours for the AA. This indicates that I will be getting 4 to 5 times the life from AA. This is a lot.
I purchased a hand light that has what must be a tiny switching supply because 1.5 volts will not run a LED. The circuit is current regulating (if these people used a similar design to the one I made) so it should be able to use much more of the available power in the battery you waste because it dropped to an unusable level. Of course you have the efficiency losses.
And now we have the newer chemistry batteries. I've even seen some prototype fuel cell batteries being toyed with the size of AA. Life is more complicated.
The Lithium batteries cost 2 to 3 bucks a battery for AA but they sure do last in a camera. They say seven times longer. Even at three bucks, this means it is a better value than regular Alkaline batteries at 50 cents each.
AAA at 1000mAh AA at 2700mAh C at 2600mAh D at 2600mAh
The reason that the AA version seem to have such a good figure is because more effort went into improving that range as it is a very popular size of cell.
My head LED torch uses three AA rechargeable cells and seems to last 4 hours on the high setting and up to 16 hours on the lowest setting. Very useful when on very dark hill-sides. My camera and portable CD player uses the same cells.
I'm tinkering with a design for a bike light using two 3W luxeon LEDs, a 2S lithium polymer pack and a microprocessor-based switching regulator.
I've pretty much given up using alkaline cells in anything I build because of the high vibration environment a lot of my stuff is subject to and the necessity to use spring contacts, I much prefer a proper soldered-contact.
I've been told that rechargeables should be used only in devices like cameras and cell phones that shut down when the voltage drops too low. Completely discharging them is said to greatly shorten their lives. Of course, a regulator can do that. There probably are available chips.
You are correct about that fact Jerry. My headtorch, CD player, Camera and other devices do auto-shutdown when the battery voltage gets too low. these little gadgets get more clever every day ;>
I'd be concerned that a light I depend on would shut down with little or no warning. That's not always a good exchange for greater life. I think of such systems as "brittle", by analogy with structures. For example, I would be more comfortable with a chain that deformed at 5 tons and broke at 8 than I would be with one that deformed at 9.5 and broke at 10.
By the way: in the early days of NiCds, C and D cells had the same rating because the Ds were actually Cs in D-cell wrappers. Could the same be true of NiMHs now?
The head torch has several brightness levels and it does have a battery state indicator which can be inspected at intervals to see how you are doing. If you were using the brighter settings when it went out then selecting the lower brightness settings would get you light for enough time to find the spare battery set (I always carry spare).
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That may be so but I wonder if anyone in the battery industry might hop up to confirm that.
At one time, I read in Consumers Union's magazine "Consumer Reports" -- see
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-- that Radio Shack was the only vendor of cells they had tested whose D cells were not wrapped Cs, and that their considerably higher (about double) capacity reflected that. I bought some. A friend who used another brand asked why my cells were so heavy. More than that, I can't say.
On Mon, 01 Jan 2007 09:27:52 -0500, Jerry Avins proclaimed to the world:
It is true for some rechargeable. The ma/hr rating gives it away. In the cases I ran across, it was AAA put in AA cases. The AA had the same rating as the AAA. You could buy a true AA if you liked, for a greater price. The company was Powersonic and I talked with the no the phone about it. I had both the fake AA and a real one. You could tell the by the weight.
On Mon, 01 Jan 2007 15:32:50 +0000, "Paul E. Bennett" proclaimed to the world:
In caving where a main light failure a mile inside the earth is a big thing, we always carry several backups. The light I would like to build would have a bypass to the electronics so you could continue. LEDs have the convenient property of putting out light at lower currents. They even get more efficient at lower currents.
Most cavers do not use rechargeable because they have less capacity and tend to let you down in the cave. It's nice to be able to use both, which I do sometimes.
It may be different in the US but when I was caving in the UK we tended to use miner's lamps with lead/acid batteries or the newer (at the time) technology of Speleotechnics FX2s. A few people used carbide lights but always had electric backup too.
On Mon, 01 Jan 2007 18:05:37 +0000, Chris Eilbeck proclaimed to the world:
A few cavers still use the miner lamp and huge lead acid battery. I used to cave with a fellow that would use nothing else. The FX2 was the upgrade to the miner lamp and was pretty popular here. A lot of us used the Pezel Duo, which is the main light I made conversions for. LEDs changed everything. Their efficiency and reliability won over most people. Many do not like the color of the white light but the better LEDs are nice yellow white instead of the harsh blue white.
I still use carbide sometimes for the sake of tradition. It has come in handy on a few trips as it the carbide light acts as bad air indicator. I carry some low wattage LED light which gives me weeks of light in my pocket. It is amazing how little light you need see well enough to move around, once you have been in total darkness for a while. That does not do you much good when you can't light up the walls or ceilings to get your bearings in one of those huge rooms you find. Lighting up a 200 ft ceiling was the main reason cavers stayed with the old mining lights but a 3 or 5 watt Luxen LED with a good focusing lens will out perform the mining lights by double now and can be powered by a head mounted battery pack.
What do you think about the rediscovery of Titan cave? I can't remember exactly where it is, maybe the Dales?
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