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Test Results That Will Change the Way You Buy Batteries Forever

Updated
By Mitch Lipka, dealnews Contributor


Evan Krell via Flickr
When it comes to batteries, how can you tell a deal from a dud? When is it worth spending money on a premium brand?

We brought a collection of different AA batteries to the Worcester Polytechnic Institute and asked if they could test to find out whether there's any real difference between brand-name and generic batteries.

The answer is that you're better off buying less expensive batteries, such as Rayovac or generics, or getting regular Energizer or Duracells on sale, because our exclusive tests show there is no measurable difference in quality among these batteries. That's right, none. So just buy whatever is on sale, take steps to make them last longer and never fret again about what type of battery to buy.

At least that goes for regular batteries. The very notable exception: The Energizer Advanced Lithium battery separated from the pack like the bunny that promotes the brand. Not only did that particular battery push out far more initial voltage than the others — when it finally corrected down to the expected 1.5 volts, it kept going and going and going.

Here's how our test worked: A team of graduate and undergraduate students supervised by Prof. Glenn R. Gaudette at the renowned eponymous institute in Massachusetts put several sets of batteries through the paces over several months. All the batteries were purchased off the shelf at retail.

Among the batteries tested were Duracell Ultra Advanced, Duracell Coppertop, a generic battery, Energizer Advanced Lithium, Energizer Max and Rayovac. All were measured for their initial voltage and how much energy they lost over 19 hours of constant use.

After 19 hours, the Energizer Advanced Lithium battery was still running at 1.5 volts — far higher than any of the other batteries. The WPI team said that it showed "remarkable stability" compared with the rest. The testers said there was no statistically significant difference between the other batteries. (See charts below.)

So, why not just buy the Energizer Advanced if it did so much better in the tests? Price. You get more; you pay more. But do you get four times more? Our latest price-check shows that Rayovac AA batteries were selling for a quarter of the price of the top-performing Energizers — 42 cents each vs. $1.42 each. The testing team also expressed some concern that some very sensitive devices could be negatively affected by the higher-than-expected initial voltage.

The WPI folks caution that the testing included only the pressure of constant demand — not the on and off usage that can be seen in real life.


Here is a survey of average battery prices, per battery, for the various brands tested:

*Price at local store.

Check out our current best deals on batteries:

  1. Energizer e2 AA Lithium Battery 8-Pack for $10 with free shipping
  2. Sony Rechargeable 2000mAh AA Battery 4-Pack for $7 + free shipping
  3. 24 Rayovac NiMH AA Rechargeable Batteries for $40 + free shipping

Deals change often, so be sure to check prices before you buy. If you want to find out about the latest battery deals, download the new dealnews iPhone/iPod app and get alerts sent to your mobile phone with the latest pricing information. Or, check out all of our Battery deals for more powerful sales.


Figure 1. Initial voltage in AA batteries. All batteries had a similar starting voltage with the exception of the Energizer Advanced Lithium, which had a significantly higher initial voltage. Credit: WPI.

Figure 2. Changes in voltage over time. Energizer Advanced Lithium started at a higher voltage, had the largest initial drop in voltage but ended with a higher voltage compared with the other batteries tested. Credit: WPI.

Mitch Lipka is an investigative journalist for consumer issues who formerly wrote for WalletPop.com, Consumer Reports, The Philadelphia Inquirer, and the Fort Lauderdale Sun-Sentinel, among other places. Follow him on Twitter at @mitchlipka or on Facebook.

Follow @dealnews for the latest roundups, price trend info, and stories. You can also sign up for an email alert for all dealnews features.

Please note that, although prices sometimes fluctuate or expire unexpectedly, all products and deals mentioned in this feature were available at the lowest total price we could find at the time of publication (unless otherwise specified).
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16 comments
buzaglo
It is not all about the voltage in measuring quality of a battery , it is also reliability !
Good luck in using no-brand "made in China" battery in your expensive electronic gadget after it will leak some nice acidic goo ...
jpezz
The best deal is at Ingles markets (a Nor or $1.25th Carolina based supermarket chain) which about half the time has Ray-o-vac on sale for either $1 for 4pk AA,AAA; 2 pack C,D or single 9V. Sales last 2 weeks then are off for 2 weeks. I never buy anything but sales and when I run low, I buy a few packs. For AA, that low price is $.25/battery. Ray-o-vac is really good. I bought some packs from Ingles that turned out to have an expired coupon offer so I called Ray-o-vac and they sent me some $1 coupons - the price I pay for the batteries which means I get them for free when on sale.
ewalsh
@dwsherwin I had read recently about this. If I can find the article I will post here.
But a quick summary from memory goes like this.
The industry doesn't recommend refrigerator or freezer storage. They say the chemicals of the battery need to be at a warmer temperature to work correctly and you are wasting power using them initially while they warm up. They say unless you store the batteries in a very hot, >150 deg F. environment that the discharge is nominal compared to the ones in freezer/fridge. They do say you should avoid high temp storage as besides speeding up discharge it can cause a leak of the cell.

They also said, condensation can form on the contacts of the battery or inside the battery if stored in a humid environment then stored in a freezer/fridge and this can cause corrosion and short.

Now I have stored alkaline in my freezer for years. I have had AA batteries where the ends looked tinned or corroded. Never had a shorted one though.
Again if I can find the article I will post here.
dwsherwin
I'm interested in knowing how to best store batteries. I usually store aa, aaa, d, c, and 9volts in the refrigerator reasoning that the cold slows down the chemical reaction inside the battery. Can anyone say if this is true or not.
atomicpop
Why would anyone buy standard batteries anymore? Rechargables are so much cheaper. The newer hybrid cells even hold a charge for months on the shelf.
DanClark
Rayovac makes many lines of batteries. Which was tested?
Is the Kirkland (Costco) battery in the photo the actual generic tested?

I've tried to be green, and save money, by buying NiMH rechargables. They last about 1/4 as long as an alkaline. Plus it's a hassle recharging and timing the recharges.

I switched back to alkaline. Kirkland from Costco has been the cheapest, though the batches I bought two and three years ago leaked. Recent batches don't leak... so far.
CHENG
I am curious as to why the chart and bar graph do not correspond to the initial voltage data. This would make me question the accuracy of the remaining data!?!?
gizmovision
Yes, I'm with the two earlier posters real world test do mean a bit more, I buy generic and good batteries, Ive had 'D' and 'E' brand batteries explode in flash lights and had 'K' brand batteries last for years in storage. Cameras will suck down the juice more than a remote will.
DetLes
Been satisfied with generics for years but no matter the brand all have had leakage after spending a couple of days in my car baking in the southern sun.
Anyone know of comparison tests on leak/burst resistance.
Taking stuff out is not an option since they are work related & guys like me use the car as an office.
ethanvyce
any thoughts to testing rechargeables? I have been using Sanyo Eneloop lately. seem to hold a charge and recharge quickly. less than a year so far; we'll see how they hold up over time
pucky
Agreed, I bought some generic no-name batteries from http://batteries.com and they leaked all over my stuff. Thankfully it didn't ruin the mouse or my Wiimotes. As the linked article about making them last longer says in #3, don't by no names. Generic brand names like Rayovac, Lowes, Rite-Aid, etc. are ok IMO.
TwoWheels
Interesting, but there is more to a battery's performance that how it drains under constant load. As one of the oter comments suggested, it would be useful to see how they performed in more typical on/off usage.

My dad would always buy cheap batteries from the dollar store or wherever,and I found the biggest difference was in mechanical construction and leak-resistance. These cheap batteries were always leaking. Sometimes they were so mis-shapen that they would not fit into devices, and they also had a higher initial failure rate (where it was unusable right out of the package).

It would be great to see a followup test on some of these other attributes..
401Kaboom
Details please! What device(s) were tested? Are they high-drain devices (digital camera?), mechanical toys, flashlights?

Why was 19 hours selected as the end of the test? At what point do the batteries no longer run the device?

I'd like to see results on NiMH rechargeables too. My understanding is that they begin fully charged at around 1.25 v, less than the voltage still available after 19 hours from the tested batteries.
Jumpman
Is Gaudette's group planning to repeat the study using a more typical load pattern with more on's and off's?
sxlsuper
cool...learned a lot from that
MNealon
Cool article. Relevant and useful. Thanks!
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