Nope: Historians tell us this "Baghdad Battery" may have been one of the first primitive power cells, a 1.1-volt unit probably used to electroplate silver. And in the years since, scientists and consumers alike have struggled to unlock the secrets inside these portable packs of power. Do batteries keep better in a fridge? Is there a difference between alkaline and zinc-carbon? What about department-store brands versus name brands? And which ones give you the best charge for your change?
As a guy who depends on batteries to make his musical gizmos go, I'm eager to know the answers, too -- and we'll charge into the fray in today's Savings Experiment.
Battery basics: Cost, life, shelft life and more
First, a few battery basics. Old-school zinc-carbon "general purpose" batteries -- especially those made overseas by no-name companies -- are worth avoiding. For starters (or non-starters, if you like), they could do your appliances more harm than good. They run out of power faster than you can say "Ben Franklin's kite," and once that happens, they're in danger of leaking acid inside your prized gadgets. Also ask yourself: When the power in your house goes out, do you want to pick up a flashlight and discover it's dead, too? It's happened to me. So if you buy a toy that says "batteries included," do yourself a favor and take out junky power cells right away. What's junky? Anything that doesn't at least say alkaline (which outsells zinc-carbon by more than 3 to 1) ... and has a label written in a dialect straight out of a "Borat" sequel.
Here's a more straight-up comparison of the major battery types for a four-pack of AA batteries, based on some of the best prices on various sites around the Web:
- Eveready Super Heavy Duty zinc-carbon: $2.09
- Duracell alkaline: about $3.50
- Sanyo rechargeable nickel-metal hydride (NiMH): $10
- Energizer e2 lithium: $12
- Dantona rechargeable nickel-cadmium (NiCd): $13
Where would I buy my batteries? Discount superstores such as Costco and Sam's Club offer savings on bulk packs (though curiously, Costco lists only small-count packs on its website). BFM Battery Sales is a battery superstore on the Internet that offers some amazing deals. You can buy Duracell alkaline AAs for 39 cents a piece. The price drops to 22 cents apiece when you order 18,600 batteries or more. Wow. That's enough cells to launch an army of remote-control monster truck toys down the nearest interstate.
How long do various battery types last? The cheapo zinc-carbon batteries will konk out fairly quick, followed by the nickel-cadmium. Alkaline will last even longer, surpassed by the NiMH and, finally, lithium batteries. But trying to get a straight answer on a simple question -- say, how long will each type will power your hand-dandy flashlight -- is like trying to research a doctoral dissertation on the Parthians.
That's because the unit used to rate battery power and longevity -- the milliamp hour, or mAh -- is measured in ranges that swing wildly depending on the device and battery type used. So, let's say you have an alkaline battery rated at 2800 mAh and an NiMH rated at 1800 mAh. Put them in your digital camera and guess what? The NiMH will actually last longer, because digital dedvices drain alkaline batteries much faster.
The most clear-cut comparison results we could find, which checked out when cross-referenced with dozens of web sites, were by photographer Andy Baird, who ranked various battery types for useful life in a digital camera. Here's what he reports:
- Alkaline: 20-30 minutes
- NiCd: 30 minutes
- NiMH: 2 to 2 1/2 hours
- Lithium: 2 hours
As for battery shelf life, that's easier to answer. And it breaks down this way:
- New zinc-carbon batteries can sit for 18 months.
- Freshly charged NiMH: 30 to 60 days, but can be recharged 500-800 times
- Freshly charged NiiCd: 45 to 90 days, but can be recharged 1000 times
- Alkaline: 7+ years
- Lithium: 10 years
Duracell copper-top batteries list their expiration dates right on the cell, a nice perk if you're opening a pack from cold storage. So yes, batteries have expiration dates, though you won't know them if they're not printed somewhere. This might make you wonder how long that generic battery sat on the store shelf before you bought it. Dust on the package? Not a good sign.
Quick chargers can fully load NiCd or NiMH batteries in about an hour, and there's no evidence I could find that they lose significant capacity over hundreds of charges (though at some point, they will simply stop working). Note that NiCd batteries are reputed to suffer from the notorious "memory effect," meaning that if you repeatedly recharge the battery from, say, 50% capacity to full, the battery will experience voltage drops at the 50% mark -- and may in some cases appear to be dead.
For this reason, NiCds can prove frustrating to use. Also keep in mind rechargeables can create major headaches if you're trying to keep track of a dozen items all losing power quickly from prolonged non-use. In my recording studio, I own about 4 dozen effects pedals, and I keep 9-volt alkaline cells in many of them. I can't remember the last time I picked up my fuzz box or digital delay after a year's layoff with any problems.
Now, on to the next question, the Big Battery Equivalent of Urban Myth: Does refrigerating batteries make them last longer? In many cases, the answer is no: Alkaline batteries (which I favor) discharge at a rate of less than 2% a year. But in cases of prolonged heat (about 100 degrees), they'll lose a quarter of their charge in a year. And rechargeable nickel-cadmium batteries (which I hate) lose a few percentage points of power every day (part of the reason I hate them).
I wouldn't feel compelled to refrigerate my batteries any more than I'd put my Diet Coke can in my radio's battery compartment. Besides, the batteries have to return to room temperature to work at full charge, one reason why battery companies don't recommend refrigerating or freezing their products.
Make 'em last
You may wonder about why cylindrical batteries come with all those letters on them: AA, AAA, D, C. The letters don't at all correspond to quality, but size. The tiny AAA battery is very skinny (less than 3/8 in. in diameter) while a C cell, at the same height of about 2 inches, is nearly an inch thick. Now if you can believe it, both those batteries have the same charge: 1.5 volts. And they're a lot easier to carry around than a Parthian clay pot full of vinegar, too. Rectangular batteries of about the same size carry a 9-volt charge, which you can feel if you touch the tip of your tongue to the two top metal contacts. Ouch!
So, how to make batteries last longer?
- Always turn devices off when you're not using them.
- Store them in a cool, dry place. This can do almost as much good as refrigerating them.
- Try not to mix worn-out batteries with fresh ones, as it places a greater strain on the new batteries. Another good idea: Keep a battery checker on hand.
- Radio Shack makes also makes a nifty little device that helps you keep track of how much life your batteries have. The Enercell Battery Tester ($9.99) tests all standard battery sizes, letting you know how much life those cells have left. Mine's never failed me yet.
- If you're a photographer or in a trade where long battery life is a must -- those who use digital appliances come to mind -- lithium batteries will offer you much-expanded life. You'll pay more -- $12 for a four pack of AAs as opposed to $3.50 for alkalines -- but you'll get so much more life out of them that the cost ends up being comparable to alkaline. A clear standout here: Energizer's e2 lithium cells.
- Only buy batteries as you need them. Sure, you're going to save money buying 200 batteries in bulk at Costco. But what good is that if seven years later, you haven't used even half of them? (The good news is that alkaline batteries will still be up to 80% effective.)
Plugging in a device through an AC adapter probably isn't going to hurt or damage your battery; it may in fact save its power. The 9-volts in my guitar pedals seem to work just fine after I run them on an adapter for a while, without any loss in battery power at all, as the adapter effectively bypasses the battery connection.
And when those batteries finally bite the dust, keep in mind that places such as Target, the Apple Store (for its laptop cells) and local pharmacy chains often offer free recycling. And if you check around, local recycling centers may pay you for dropping off spent batteries. Check with your local municipality to see which service providers might offer such incentives.
Chemically speaking, no battery is truly environmentally friendly. Batteries rank among the most troublesome items for folks to recycle, even "greenies" like me. The city of Chicago's curbside recycling program, for example, takes glass, paper and plastic -- but not batteries, which means many consumers just toss them in the trash.
Because NiMH cells can be used so many times, they'll save space in landfills: 500 recharges means 500 batteries not leaking. But there's no such green benefit from other rechargeables. NiCd (nickel-cadmium) batteries are virtually banned in Europe because of the environmental hazards of cadmium.
Conclusion: Don't cell yourself short
So what are the constants in Battery Life Bingo? From lithium-ion computer cells to disposable batteries, remember to only use batteries when you absolutely have to. Computers will run better on AC power than their batteries, and again, keep devices switched off when they're not in use to keep batteries potent. And whatever you do, keep it cool: Batteries hate extreme heat. If you see a leaky battery, get rid of it immediately. And keep in mind that once you have used a fresh disposable battery for the first time, you shouldn't store it for a long period of time -- the batteries will drain much quicker.
In terms of which batteries are best, alkaline cells will hold up very well for most common uses, and differences between the major brands -- Energizer, Duracell and Rayovac -- appear negligible, though in my experience, the alkalines sold under the CVS and Walgreens banners work almost (but not quite) as well. For disposables, it's hard to beat the durability and dependability of Energizer e2s and other lithium cells, which I love to scoop up whenever they go on sale.
But in the end, NiMH batteries offer the best overall value, with one important caveat: You'll drive yourself crazy recharging them every month or so if you use them in devices that sit for long periods of time. For digital cameras that get an intense workout? Can't beat 'em.
What's more, new "hybrids" by Sanyo promise to extend the shelf life of NiMH batteries significantly -- to more than a year -- though they'll also be more expensive in some cases, and won't work for as long in your devices. But hey: When we found four AA Sanyo Eneloops for $10.84 (regularly $15) on Amazon, we have to say that the light bulb went on. Big time.
What would the ancient Parthians think of all this? Or the Energizer Bunny? You know, I could keep going ... and going ... and going ...