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The claim is

Duracell Duracell claim in *

Up to 10 times longer lasting power

(*) vs. ordinary zinc carbon batteries in high powered toys and flash cameras

(picture from Amazon)

Do Duracell batteries last longer than Zinc Carbon batteries?

If so, how much of the ten times part is true?

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Dudey
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    Note that this is not primarily a comparison between Duracell and other *brands*, but between these Duracell *alkaline* batteries and a different *type* of battery. – Dan Getz Jun 12 '16 at 11:00
  • Indeed, I don't think I've ever seen a zinc-carbon battery, presumably due to how rubbish they are. – OrangeDog Jun 14 '16 at 08:52
  • @OrangeDog Where I live most popular brand ones are genrally Zinc-carbon (Nippo, Everyday). – Dudey Nov 20 '16 at 14:04

2 Answers2

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Zinc-Carbon and Alkaline batteries are different battery types. The have a similar voltage and come packaged identically, however the amount of stored energy varies greatly.

Comparison of battery types

Comparison of battery types

As you can see, alkaline batteries, such as Duracell, can store up to 5 times more energy in the same volume.

However, alkaline batteries also have a better energy efficiency, up to 85% against up to 60% (i.e. a difference is what percentage of the energy in the battery can actually be used). Alkaline batteries also self-discharge twice as slowly as zinc-carbon ones.

All these factors are what probably justifies the claim by Duracell -- that said, I've found no evidence that Duracell batteries are any better than other brand alkaline batteries, which is what the claim seems to imply, but not say outright.

Sklivvz
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    For evidence see UK consumers organisation Which? http://www.which.co.uk/reviews/batteries?sortby=which_score_desc&page=1 this is possibly behind a paywall – mmmmmm Jun 12 '16 at 14:44
  • @Mark I am not familiar with which but it doesn't seem authoritative, more like a comparison shopping site (difference being that I don't want to see how products pair up, I want to see the statistically valid performance of duracells against market average) – Sklivvz Jun 12 '16 at 15:24
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    Which? Is indeed a comparison shopping site, but it's a good one with a high reputation and a lot of Independence, and regularly performs it's own standardized testing. – DJClayworth Jun 12 '16 at 18:20
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    I can see that the "long lasting" claim could be justified by the lower self discharge rate (e.g. in a flash light you only use occasionally over years) but I wonder why they specify "high power"? I can't find anything to suggest that alkaline performs better in high current applications. – Keith McClary Jun 14 '16 at 14:34
  • @KeithMcClary not sure where you read "power". When they claim "longer lasting power" they are simply saying "their electrical power lasts longer", which is equivalent to "they store more energy". – Sklivvz Jun 14 '16 at 14:55
  • [Here is a "Technical Bulletin"](http://media.ww2.duracell.com/media/en-US/pdf/gtcl/Technical_Bulletins/Alkaline%20Technical%20Bulletin.pdf) where they support the claim. – Keith McClary Jun 14 '16 at 16:58
  • It's a classic case of comparing their product to the absolute worst competition. Compared to other alkaline batteries of reasonable quality they don't last any longer, and cost around 5x as much. For example, they are comparable to IKEA alkaline cells which retail for around 12p each, but Duracell are typically >50p each. –  Jun 15 '16 at 08:26
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Not really. The trick they use is to compare to zinc-carbon batteries, which as Sklivvz points out in their answer are approaching 10x worse. Higher discharge currents magnify the effect, but it also very much depends on the device as some can work with lower voltages than others.

However, in general the claim that is often made on TV, without the caveat about only comparing to zinc carbon that Duracell are significantly better than other brands is untrue. For example, compare these datasheets from Duracell and Panasonic:

http://professional.duracell.com/downloads//datasheets/product/Simply/Simply_AA_MN1500.pdf

https://na.industrial.panasonic.com/sites/default/pidsa/files/1.5vseries_datasheets_merged.pdf

(the equivalent Panasonic cell is the LR6XWA)

Note the discharge curves at various loads are almost identical. Duracell has no advantage at all, and in fact performs slightly worse under heavy load. The other issue is quality, and Panasonic are popular with industrial applications due to their high reliability and consistency, where as Duracell are more of a consumer oriented brand.

Unfortunately I was unable to find a datasheet for IKEA or another cheap brand of alkaline cell, but but in informal tests (http://www.batteryshowdown.com/static/images/mah_large_200mA.png) they tend to perform similarly to Duracell's most expensive cells at a small fraction of the cost, sometimes as little as 1/10th the retail price.

In short, Duracell's claims seem to be from a time when alkaline cells were new and much more expensive than zinc, but nowadays are simply misleading due to alkaline cells being barely more expensive (5-10%) and what consumers are likely comparing against.

  • In India normal batteries are all cheap Zinc-Carbon. Duracell seems to be the only popular brand selling Alkalines. – Dudey Jun 15 '16 at 09:22
  • The lower self discharge rate can make a big difference in some applications like smoke alarms. However Panasonic make be as good a Duracell for this these days. – Ian Ringrose Jun 21 '16 at 09:30
  • Panasonic are the more reliable and consistent for quality, better than Duracell who in fact re-badge some Panasonic parts (e.g. Eneloop). Unfortunately there are also a lot of knock-offs and Panasonic themselves still make Zinc cells for developing markets. –  Jun 21 '16 at 12:55