Alkalines have plenty of appeal: high energy capacity in relation to the (modest) price, fine low temperature performance, and a shelf life of up to five years in cool storage. Each year, new technology improves alkaline batteries, with every new generation superior to its predecessors. Look for the latest versions such as Energizer Advanced Design, Varta Photo AA Titanium Plus, Panasonic Plus, Duracell ULTRA, or Kodak Photolife, for the very best performance (often 20 percent better than older versions). Even today, some 67 percent of all batteries sold are alkalines, and this is understandable given their exceptional versatility.

The NiCd Rechargeables. Some photographers feel it's wasteful to use disposable batteries, so they buy rechargeables instead. The up-front cost is higher, but they do save money in the long run. Unless you frequently travel far from a handy electrical outlet, this type should prove to be highly practical for camera and flash. Still the most common, the Nickel Cadmium (or NiCd) batteries are great in flash especially, as they offer quicker (and more constant) recycle times: about 6 sec vs. 10-15 sec on average, in a Sigma EF 430 ST flash in my unscientific tests.

Note: The best alkalines will provide double the number of flashes, and not all equipment was designed to accept NiCds, for a variety of reasons, including the lower (1.2v vs. 1.5v) voltage in AA size. Check your Owner's Manual before making a switch. The new special "Quick Charge" NiCds can be charged in two to five hours. However, never attempt to charge ordinary NiCds in a "quick charge" unit; overheating or an explosion may result.

When shopping look for the latest technology, denoted by claims such as "40 percent longer life than those of a few years ago" or "quicker recharging" feature. For example, the latest Panasonic Rechargeable 1100 models have very high capacity (1100 milliampere hours or mAh) and are sold with a five hour recharger. (For most previous NiCds, 750-850 mAh is standard; for rechargeable alkalines, 900 mAh is typical, although some have capacity as high as 1000 mAh.)

Dispose of NiCd batteries with caution--read the manufacturer's instructions--as the contents are toxic. Some retailers will accept "dead" NiCds if you purchase a new set, for return to the manufacturer who will recycle them. (Before disposing of batteries of any type, check with your municipality as to approved procedure.) Frankly, the greatest drawback of NiCds is the "memory effect." If recharged before they are completely drained, they will "remember" and may not subsequently accept a full charge. Fortunately, "voltage depression" (the correct term) is a temporary and reversible effect with the latest NiCd batteries.

Other Rechargeables. A few manufacturers--including Pure Energy and Ray O Vac--offer special "rechargeable alkaline" batteries with a charger intended solely for this type. Note: Chargers made for NiCds are not suitable and conventional alkaline batteries must never be recharged. With these systems, avoid deep discharge; for the best results, recharge them frequently, every evening after use. (There is no Memory Effect problem; quite the contrary, in fact.) With a higher energy density than NiCds these offer more flashes and hold their charge for years while not being used. The only drawback--as compared to NiCds--is that they will not tolerate hundreds of recharge cycles if the batteries are subjected to deep discharge.

Touted as a superior rechargeable battery, the Nickel-Metal Hydride (Ni-MH) types have been common in sizes for portable computers and camcorders. Until recently, only one company, Harding Energy Systems, offered such batteries in the AA size (1.2v vs. 1.5v like alkalines). Now two new and similar kits are available, with four cells and a compact charger. The Kodak's Photolife (1450 mAh) and Olympus B-30-SU (1300 mAh) kits are similar, and we expect to see others soon. Environmentally friendly, they contain no cadmium, mercury, lead, or lithium. Ni-MH uses a metal alloy negative electrode in place of a cadmium electrode, allow- ing for greater energy storage (hydrogen, in the form of hydrides).

The primary advantages claimed (over NiCds) include quicker recharging (three hours), longer life, and constant voltage in high-drain applications plus no Memory Effect. Most useful in flash units, they shorten recycle times considerably. With a Sigma EF 430 ST flash unit for example, recycle times (on average) were 6 sec with Ni-MH batteries and 10-15 sec with alkalines. I got a few more flashes per set with the conventional batteries but recycle times became extremely long after extensive use.

Note: With alkalines, recycle times with flash begin to get longer and longer (20+ sec) as battery power becomes lower. With most rechargeables, this does not occur and they tend to "die" suddenly without that warning.

The Lithium Edge. Most new cameras require lithium manganese dioxide cells, generally referred to as "lithium." With better cold weather performance and "double the energy density" they're more compact and lightweight. More importantly, lithium's high power output offers increased hours of service, with greater staying power especially under heavy load.

Thanks to a "flat discharge curve" they maintain a constant voltage level for most of their useful life. Granted, they are far more expensive than alkalines and under very heavy load--autofocus plus built-in flash--their useful life is not as long as you'd expect. Nonetheless, they last longer than alkalines with double the in-use life--and triple in the compact point-and-shoot cameras--in my unscientific tests. This makes the lithium battery a suitable choice for today's cameras and flash units--especially the improved versions. One recent example is the new Panasonic Rapid Flash, said to offer 50 percent more flashes (with built-in heads) than their previous lithium models.

For equipment which requires AA batteries, look for the Eveready Energizer High Energy lithium employing a lithium/iron disulfide chemical system. Optimized for use in photo equipment, these were designed (with high current output) to meet the specific needs of cameras and, particularly, electronic flash. Weighing a third less (15g vs. 23g for alkalines), they deliver far more energy for less weight. With flash, recycle times are shorter: averaging 7-8 sec vs. 10-15 sec for alkalines, in my tests. Again, recycle times do not become extremely long as the lithium batteries are close to exhaustion. This minimizes the risk of missing a decisive moment while waiting patiently for the "ready" light.

Note: The manufacturers of some cameras and flash units (especially models over 3 years old) recommend against the use of lithium AA batteries, warning that they may damage the electronics. Check your Owner's Manual or ask a knowledgeable dealer. Ener-gizer's guarantee states, "We will repair or replace any device damaged by this battery on receipt of both."

Miniature Batteries. If your camera takes button cells, its power demands are considerably more modest. Consequently, it's well worth switching to lithiums from the mercuric oxide (1.35v) types which are disappearing from the market due to environmental legislation. However, many SLRs will not accept the 3v lithiums; ask a photo dealer to check his compatibility charts before any substitution. If necessary, switch to silver oxide cells instead, purchased from a photo retailer. As with any chemistry, batteries intended for hearing aids and other equipment will not provide suitable performance with a camera.

Silver oxide cells do run down more quickly than lithiums, but for some cameras, they are the only alternative to the highly toxic mercury chemistry. Look for the newer types such as those from WeinCell (zinc/air composition) from The Saunders Group. Voltage may differ from the mercury cell you used previously, so do read the manufacturer's warning or recommendation closely.

Other Power Sources. Frequently used by press and wedding photographers, the accessory battery packs for portable flash units meet professional demands. Similar in concept to those in your car--sealed lead/acid cells, but filled with a gelled electrolyte--these are also rechargeable. They offer far greater capacity than any other type, for extended life and numerous flashes with almost instant recycle (1 or 2 sec). Quantum Instruments, Lu-medyne, and Dyna-Lite models are the most common but you'll find several other brands, including those from flash manufacturers. (Various power packs for studio flash are also available but these are beyond the scope of this review.)

Note: Lead/acid cells are not recommended by some equipment manufacturers for their systems. Citing heat buildup which would reduce the flash unit's life, some will even void the warranty. On the other hand, I have tested the Quantum products without any problem, while thousands of photojournalists claim they successfully use various packs with confidence. Read the battery manufacturer's safety tips and heed all the pertinent warnings. Discuss the compatibility issue with your photo retailer, and check the instruction manual or warranty of the power pack you're considering. Or check out the alternatives offered by certain camera/flash manufacturers; some offer accessory battery packs which use NiCd or large alkaline C or D cells instead.

A few camera manufacturers offer remote battery packs for certain models of 35mm SLR cameras. (Check the brochure or Owner's Manual for your camera or ask a knowledgeable photo retailer.) The most common type includes a cord so you can keep the battery pack in a warm pocket, a significant advantage in extreme cold. Other types attach to the base of the camera, replacing a single lithium cell (or four AAs) with more AA batteries for higher power capacity. The latter accessory is less useful in cold weather but allows you to use the more affordable battery types.

Conclusion. Although inexpensive testers are available (and some AA batteries are sold with a tester), these are of little value for lithium batteries. This type needs to be tested "under load"--as if it were actually powering some equipment at that moment. When shopping, insist on a unit clearly marked as "testing under load," like the new Multi-Battery Tester from ZTS Inc.

After your photo equipment calls for fresh batteries, don't toss out those you remove. In most cases, they still contain enough juice to power a flashlight, compact 35mm camera, or other device with lower current demand. Follow the tips and rules for safety provided by the manufacturer for maximum satisfaction with any battery type. Next to film, a power source is the most essential accessory we photographers carry. Treat batteries with respect, and they will reward you care by living up to reasonable expectations.

Top Ten Battery Tips
Both user safety and the service life of any battery can be maximized through the use of a few common-sense precautions, listed below:
· Fully charge NiCds but do not "top up" regularly; use a 14 hour "trickle" charger except for those designated as "quick charge" NiCds.
· To prevent an explosion, never recharge batteries unless marked as "rechargeable," or throw any type into fire.
· To conserve power, resist the temptation to play with your camera; remove batteries if stored for over a week to prevent trickle discharge.
· Never mix batteries of different chemistry; replace batteries as a set, not one at a time, to maintain reliability.
· Read your equipment Owner's Manual before substituting battery types.
· Store batteries in a dry place, at 10-22°C; avoid excessive heat or cold.
· If a battery is swallowed, call the nearest hospital immediately for advice.
· Keep terminals clean, avoiding skin oils; rub contact points with a pencil eraser to remove contaminants.
· Rotate sets of batteries in cold weather, with spares kept warm by body heat.
· Avoid contact with keys, coins, and other metal objects to prevent a short circuit.
· Carry spares when traveling, unless using battery types which are universally available.

Manufacturers/Distributors
CWE/JRS (Pure Energy)
51 Elaine Rd.
O' Fallon, MO 63366
(800) 365-6174
fax: (800) 875-4871
www.cwejrs.com

Duracell U.S.A.
Berkshire Corporate Park
Bethel, CT 06801
(800) 238-4354
www.duracellnpt.com

Dyna-Lite
1050 Commerce Ave.
Union, NJ 07083
(800) 722-6638
(908) 687-8800
fax: (908) 686-6682
www.dynalite.com

Eastman Kodak
343 State St.
Rochester, NY 14650
(800) 242-2424
fax: (716) 724-5629
www.kodak.com

Eveready (Energizer)
800 Chouteau Ave.
St. Louis, MO 63102
(314) 982-2000
fax: (314) 982-4078

Harding Energy Systems
One Energy Centre
Norton Shores, MI 49441
(616) 798-7033
fax: (616) 798-7044

Lumedyne, Inc.
6010 Wall St.
Port Richey, FL 34668
(813) 847-5394
fax: (813) 841-0000

Olympus America Inc.
2 Corporate Center Dr.
Melville, NY 11747
(800) 622-6372
(516) 844-5000
fax: (516) 844-5262
www.olympus.com

Panasonic Industrial Co.
Two Panasonic Way, #7A-3
Secaucus, NJ 07094
(201) 392-4675
fax: (201) 392-4242
www.panasonic.com

Quantum Instruments, Inc.
1075 Stewart Ave.
Garden City, NJ 11530
(516) 222-6000
fax: (516) 222-0569
e-mail: QuantRep@qtm.com
www.qtm.com

Rayovac Company
601 Ray O Vac Dr.
Madison, WI 53711
(608) 275-3340

The Saunders Group
21 Jet View Dr.
Rochester, NY 14624
(800) 394-3686
(716) 328-7800
fax: (716) 328-5078
www.saundersphoto.com

Sigma Corporation of America
15 Fleetwood Ct.
Ronkonkoma, NY 11779
(516) 585-1144
fax: (516) 585-1895
www.sigmaphoto.com

Varta Batteries Inc.
300 Executive Blvd.
Elmsford, NY 10523
(914) 592-2500

ZTS, Inc.
6749 Bramble Ave.
Cincinnati, OH 45227
(888) 796-2777
fax: (513) 272-1383
www.ztsinc.com