Buying Guide: Rechargeable Batteries


How to choose the right batteries and get the most power. We are living in powerful times. Literally.

Many batteries currently available completely outclass those of a scant few years ago. But you can’t just go out and “buy a battery” without first giving a little consideration as to what you’re going to use it in.

Read on so you can buy a battery that will keep your camera going, and going, and going...

There are four basic types of batteries that photographers use: Cylindrical (e.g. AAs), button, three- and six-volt lithium, and prismatic. Single units such as the familiar AAs are properly called cells, but the term battery (technically a multi-cell assembly such as a 9-volt transistor battery) is popularly applied to all such devices.

For each kind of battery, there is a wide selection of formulas to choose from. The correct choice will depend on your particular application. Let’s get down to the specifics of the more commonly used non-rechargeable (also known as "primary") batteries.
A wide variation in chemistry is found in cylindrical batteries. These include D, C, AA, AAA and N sizes. Most photographic applications use the AA and AAA sizes.

For all practical purposes, standard or so-called heavy-duty zinc-carbon cells are useless for photographic applications. Save them for your flashlights. Alkaline cells are the most widely used in most photographic applications—particularly in film winders and electronic flashes. They are relatively inexpensive, and are frequently discounted or rebated at major hardware suppliers. They do, however, have a short life when put into digital cameras. Here, you have other choices.

Digital batteries

For cells that are more suitable for use in digital cameras, you need batteries with different chemistry. Energizer AA and AAA lithium cells are a prime example. They are lightweight--33 percent lighter than alkaline cells. They operate well in temperatures. Indeed, lithium cells will continue to operate at temperatures ranging from -40 to +140 degrees F, a range that includes many conditions under which alkaline batteries would fail. They also have a 15-year shelf life.

Other digital-friendly AAs include Kodak’s Max and Panasonic’s Poweredge units. Why do these three types work better in digital cameras? The main reason is that they put out about 1.7 volts rather than the typical 1.5 volts of alkaline cells. Here’s how it works.

UPDATE Feb. 1, 2006:
The new most power-per-penny champ: Panasonic Oxyrides

Recently, Panasonic has made some claims about its Oxyride AA batteries, which cost approximately the same as standard AA alkaline batteries. In a recent test conducted by the New York Times to see if these claims held true, Panasonic Oxyrides produced 844 shots per charge, compared to 354 shots using regular alkalines. Premium alkalines gave 566 shots. While they may not be as economically or environmentally friendly as, say, rechargable batteries, it looks like Oxyrides are currently the best value among disposable batteries.

Electronic flashes and digital cameras draw the highest instantaneous current when first turned on and immediately after each shot. Current draws as high as two to three amperes are typical. This high current draw causes the battery’s voltage to drop temporarily due to its internal resistance. This presents no problem for an electronic flash. As the flash’s main capacitor charges, the current draw drops and the battery voltage comes back up. But digital cameras are more fussy. They need a bit higher voltage than flash units to keep all the goodies working properly. Digital batteries are designed so that their voltage remains higher under high current loads. This keeps digital cameras happy.

Will you get longer service by using these cells in your electronic flash or flashlight? Not really! With the notable exception of the Energizer lithium cells, you will get no appreciable benefit from using them in your non-digital gear—especially considering their higher cost.

The Energizer lithiums are really great. When you’re carrying a heavy camera like a Nikon F100, you can use all the weight savings you can get. And these babies are light and long lasting! By the way, they are quite different from other lithium cells in that other types—i.e. button and prismatic lithiums—put out 3.6 volts per cell.

Love those lithiums!

Three and six-volt lithium batteries are widely used in digital and film cameras. They include the CRV3 CR-P2 and CR2 types, and they’re long-lived and work quite well. Six-volt batteries consist of two 3-volt cells.

Prism batteries are a recent variation of the above-mentioned lithium batteries. The Duracell CP1 is a high-power lithium primary prismatic battery designed specifically for digital cameras, and is used to power some of the smallest, slimmest digital cameras on the market.

The prism battery offers consumers a new level of convenience by delivering strong power in an easy-to-replace, always-ready form. With a flat, rectangular shape that is only 7 millimeters thick, the Duracell CP1 provides always-ready power that ensures that consumers will never miss an important photographic moment because a rechargeable camera battery has not been charged. Owners of digital cameras designed to accept the CP1 battery can choose between using a disposable battery or a rechargeable one, depending on their photographic needs.

Button cells: bad news/good news for camera collectors

Button cells have been around for a long time and also are available in a variety of chemistries. They come is several sizes too, including some that are really a bit larger than most buttons. earliest button cells were the mercury type. They produced from 1.35 to 1.4 volts per cell, depending on the model. These are, much to the dismay of vintage camera lovers, no longer available for ecological reasons. Current button cell chemistries include manganese dioxide, silver oxide, lithium and zinc-air.

Manganese dioxide buttons supply 1.5 volts per cell. While they come in the same physical sizes, as most mercury cells did, because of the voltage difference, they are not entirely interchangeable with them. Silver oxide button cells deliver about 1.55 volts per cell and can provide more total energy than alkaline cells. Using these cells in most cameras designed for mercury cells can cause exposure inaccuracies.

Zinc-air cells, made by Wein Products ( are a different kind of animal that can be used in vintage cameras. They put out 1.35 volts per cell, relying on oxygen from the air to generate electricity. Since this requires tiny holes in the cells’ cases, they are sealed with an adhesive tab prior to use. Removing the tab starts them working. The downside of zinc-air cells is that they dry out in a few months because of the air holes. You can reseal them between uses to their life, but it’s a bit of a bother.

I have run Wein cells on a simulated load for over three months. None of the 625 or 675 Wein cells outputs decreased at all over 18 weeks. Indeed, their output actually increased by a few thousandths of a volt over the test period. The 400-type cells, being smaller, lasted only 5-6 weeks on the same 200-microampere load. This is just about what would be expected from these smaller cells. The equivalent mercury oxide 400 cell would have almost exactly one-third the capacity of mercury 625 and 675 cells.

The other mercury replacement I tested under the same conditions was the MR-9 adapter distributed by C.R.I.S Camera Services. This device consists of a metal cup into which you place a 76 silver-oxide cell such as a Varta V76PX. The MR-9 contains a small circuit that drops the battery’s 1.55 volts to a nominal 1.30 volts.

In our tests, the MR-9 lasted 4 weeks and delivered about 1.30 volts throughout the test. Multiplying 200 microamperes by 30 days works out to just over 140 milliampere-hours--the specified capacity of the V76PX. In actual operation, the V76PX would last much longer than 30 days since this type of battery will not dry out like the Wein cells when it’s not actually being used.

The bottom line: A very occasional vintage camera user would be likely to get better service from the MR9, while the heavy shooter may find the Wein Cells more cost-effective.

You can get information on the MR9 on the C.R.I.S web site, where the adapter can also be ordered. The price is $29.95 plus shipping and handling. A silver 76 cell from the same source is $2.90. Their phone number is (800) 216-7579.


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