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Sources for my battery comparison table

Voltage is from product packaging, except:

  • NiZn from PowerGenix site (PDF).  PowerGenix can't make up their mind about the nominal voltage, and they list it elsewhere (such as on the packaging) as 1.6 instead of 1.65.  I'm using 1.65 in the table because these batteries are even hotter fresh out of the charger, and the extra voltage can fry devices, so it's better that I show the voltage as higher rather than lower.
  • Lithium voltage is 1.5 on the package, but I and many others have measured some between 1.6-1.8.
  • Oxyride from Wikipedia and TechLore.

mWh figures:

  • NiZn from product marketing.
  • Alkaline from ZBattery.
  • For the rest, I calculated mWh by using the same mAh-to-mWh ratio shown at StefanV for NiMH & NiCd (1.14x for AA/D, 1.1x for AAA), and ZBattery for the others (1.15x for AA/D, 1.16x for AAA). 

mAh/capacity figures:

  • NiMH/NiCd is from product packaging of various brands.
  • NiZN from the manufacturer (PDF).
  • For Rechargeable Alkaline AAA/AA, the high figures are from Juice (PDF) and a Pure Energy retailer, while the low figure for AA is from an engineer's measurements. Rechargeable Alkaline D-size is from Accucell. Alkaline mAh is from ZBattery
  • I couldn't find mAh or mWh figures for Oxyrides, but the NY Times test showed they took 1.5 more pictures in a digital camera than premium alkalines. 
  • Lithium AAA is from Energizer (AA PDF, AAA PDF).
  • Carbon-Zinc from Rayovac (PDF), All About Batteries, Solarbotics.

Recharge Cycles:

  • NiMH is 300-1000 per Thomas Distributing, 400-600 per Battery Canada, and 100-800 per PowerGenix.  Sanyo claims 500-1800 for various flavors of eneloopCadex's testing showed 700 cycles to be practical for an older (non-LSD) NiMH).
  • NiCd: Cadex terminated their testing at 2300 cycles and their battery pack still had close to 100% capacity.  Up to 500 cycles per Hardware Secrets, "typical life is over 500 cycles" per Electropaedia, 100-800 per PowerGenix.
  • NiZn: PowerGenix claims 100-500, but they don't specify the depth of discharge.  NLee says he found technical data on PowerGenix's site that said the deep-discharge cycle life was only 200 cycles, though I couldn't find it (probably no longer available).  My own experience was pretty bad:  After about a year of using them in electric toothbrushes and electronic door locks (perhaps 10 cycles), 7 of 9 cells dropped to 45-150mAh, and the remaining two were 996 and 1298.  They should be 2500mWh ÷ 1.65V = 1515mAh.
  • Rechargeable alkalines are claims for Pure Energy (from Sundance Solar), Lenmar, and Juice.
  • Alkaline cycles from my experience.
  • Oxyride from Joe Horn.
  • The definition of Cycle Life (the number of charges while retaining ≥60% of the initial labeled charge) is from Energizer.

Self-Discharge Rates:

  • Shelf life is often defined as how long a battery can last unused and still retain 80% capacity. (Energizer PDF, p. 13, and Pure Energy)
  • NiMH:
    • Figures in the table are from independent testing.
    • Sanyo's graph shows standard NiMH retains 50% after six months and 0% after one year.
    • Sanyo says their normal eneloop retains 75% after two years, while their eneloop 1500 retains 85% after one year and 75% after three.
    • For NiMH/NiCd, discharge rate doubles for every 18∞F (10∞C) increase in temperature. (Battery University)
    • Refrigerating batteries slows self-discharge for NiMH by about half, but the easier solution is to just buy the Low Self-Discharge flavor of NiMH in the frist place.  (Contrary to myth, refrigerating doesn't slow self-discharge for alkalines, and alkalines hold their charge for a long time anyway).
  • NiZn from NLee the Engineer.  Note that PowerGenix (the manufacturer) claims 8%.
  • NiCd from Battery University.
  • Rechargeable Alkaline from Juice (PDF). Note that Pure Energy states <1%/mo., Fig. 15.
  • Alkaline from Panasonic (PDF) and Energizer (PDF).
  • Lithium from Energizer (PDF, p. 13, and website)
  • Carbon-Zinc Energizer (PDF).

% capacity at cold temps:

  • NiMH from Panasonic (PDF, and additional note), and Sanyo.
  • Rechargeable Alkaline from Pure Energy, Fig. 13.
  • Alkaline from Energizer (PDF) (75% @ 50mW discharge, 41% @ 250mW, 35% @ 500mW, 31% @ 1000mW).  Alkaline much worse at sub-freezing temps (for the first table on this page) from Energizer (PDF, p. 5) and Climber.org.  That second Energizer doc also suggests that all flavors of alkaline are similar.  Alkaline from J. Harper.
  • Lithium is Ultimate Lithium from Energizer (PDF) (96-98% @ 50-250mW discharge, 87% @ 500mW, 82% @ 1000mW)

Temperature range (operating):

Self-discharge slowed by freezing temperatures:


Commonly available since...:
  • NiMH:
    • Normal: From my own observation
    • LSD:  Eneloop available since 2005 as per Sanyo.
  • NiZn from PowerGenix press release.
  • Alkaline from Duracell, Battery Technologies Inc.
  • Oxyride from Panasonic press release. Lithium from Energizer.

Related websites

Fan Mail

I've been searching battery stuff on google for quite a while and usually the sites are ok at best. Thankfully i found your site today and I think it is without a doubt the best by a longshot. -- Jeff D.

Thanks for your site. It has been very helpful. I want to share this info: I just purchased a Postal scale which came with a 9-volt battery of a type apparently not covered in most sites. It says it is a Mercury-Cadmium battery and looks to be of Japanese manufacture. With both Mercury and Cadmium, it probably ranks high on the list of the EPA's worst nightmares. Ironically, it comes with a "Postal" scale, pitting bureaucratic agencies against each other. -- Edward Frank

I'd never heard of Mercury-Cadmium batteries and couldn't find much on the net about them, but they're apparently a rare type becoming even rarer because of, not surprisingly, environmental considerations.  My guess is that they were bundled with certain devices from foreign manufacturers (like the one you bought) but are not available individually to consumers in stores, at least not in the U.S., and probably never were. - MBJ

I've had an old Nickel Cadmium battery charger for ages (7+ years) and just bought some Nickel Metal Hydride batteries today.  When I put them in the charger I just happened to notice a warning saying not to charge any type other than Nickel Cadmium.  Well I wasn't sure if NiMH was close enough -- so I searched on the web and found your . . . dare I say "exhaustive"? . . . site.  After some looking around at the Chargers page and Battery Types page I found the Charging Tips area and from there the answer to my question: Don't recharge NiMH's in an old NiCad charger!  The further information found on the link in that question ("more on this topic") was helpful too. Thank you very much for going to all the effort to provide this resource to us laymen. -- HCDearmore

Great site! Short, concise information, which aided my buying decision. I really appreciate your efforts and cutting through all the marketing speak. Thanks! -- Erik Martin

WOW! What an EXCELLENT site! I found your site extremely informative, THE source for all my battery questions. Too often there's a lack of info on these subjects, but your site answered everything. I'll be recommending this site highly to all my fellow photogs and others. Keep up the great work! -- K.A.H.

Great review! Simple, concise and full of facts! Appreciate your efforts and I am sure many others learned a lot too! I have used batteries for many photo applications for years and found your facts to be truthful with a lot of great anecdotes that cut to the chase quickly. -Zapper777

Thank you so much for your battery web site (which I found using Infoseek) I had been wondering about the new NiMH rechargables and lithium vs alkaline stats. Your information was appreciated. -Ron Graber, Carthage, MO

[We reviewed battery chargers for WIRED magazine for its May 2000 issue.]

[Men's Health magazine wrote to us in June 2000 asking about information for an article.]


©1999-2013 by Michael Bluejay ï I have tried to verify all the information on this page, but I ain't responsible for no errors or omissions, bucko.



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