Battery Life
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Notes collected from the Climber.Org Gear Forum, which generally reached the consensus that "it all depends on what you need":

Few of us (me included) have ever taken more than one set of batteries and used them in a similar enough way to obtain a valid comparison. Hopefully the comments below will help you choose wisely!

Note from Roger in 2011: There is a new and very interesting rechargeable battery technology out there that is not talked about on this page. The technology I'm talking about is NiZn which puts out 1.6v and is available in AA and AAA formats. I'd be curious to know how they stack up against the Lithiums, Alkalines, and NiMH for cold weather performance. I'm also curious to know if they could be used in an avalanche beacon. I know that Barryvox offers new firmware which allows you to get accurate battery life readings for Li or Alkaline batteries but I don't know if either of those settings would work ok for the NiZn batteries. I have sent them an e-mail to find out if one can safely use NiZn batteries in their avalanche beacons or if they're looking into it at all.

carrying spares is a function of battery size/weight/type

Richard Schwaninger wrote: I use the [Petzel] Zoom on longer trips and I always use the 4.5 V battery. It lasts... well, I don't quite know [how long] since I replace the battery before each trip.

Paul Wilson wrote: My old headlamp uses 2 AAA batteries. And I use fresh ones for trips that need a full charge. The used batteries go on the shelf and I use them for my mag light in my shop and the battery eating GPS. I seem to have a good supply of used batteries.

Steve Eckert wrote: That's the big problem with the big battery. I prefer smaller batteries that I don't mind carrying spares for. The big ones are so heavy I've almost never seen anyone carry a spare, but I have seen a couple of DEAD big batteries because the headlamp turned on in a pack and ran all day. Rhetorically, what do you do with all the 1/4-used battery packs? I switched from expensive to cheap alkalines because I always carry spares and I almost never run the first set down. The cheap ones are lighter, so this way I'm carrying less weight. That's not going to be reflected in ANY manufacturer spec!

Craig Smith wrote: I always keep a set of regular lithiums in my pack as an emergency backup. These will last for years w/o self-discharging, and are nice to use if your rechargeable batteries run down before the end of the day.

GPS (etc) battery meter shows remaining life incorrectly for NiMH

Kevin Craig wrote: I tried NiMH in my Garmin (eTrex's and 12XL). There is some kind of incompatibility between the battery meter algorithm in the Garmins and the 'power curve' or whatever it's called for NiMH batteries that causes them to always register as much less than 'full' even with fresh batteries right out of the charger. Since I like to know how much juice I really have left, I abandoned them in favor of the LiIon which seem to work OK.

Craig Smith wrote: Regarding batteries for the Garmin GPS: I have an eTrex and use rechargeable Nickel metal hydride batteries most of the time. Works fine with very reasonable battery life. As someone else mentioned, the output voltage of the NiMH batteries is lower than the alkaline or lithium for which the eTrex is designed, so the battery capacity bar graph will read less than 'full' even with a newly charged NiMH battery set. But the life will be as good or better than a set of alkalines.

Rich Feldman wrote: An independent issue is the low-voltage cutoff of the equipment. NiMH drop to 1.2 volts early in the discharge, but hit 1.1 just before exhaustion. With alkalines, most of the energy is delivered above 1.25 volts, but you are throwing away a useful fraction if you stop at 1.2 or even at 1.1.

longest-lasting battery is different in high vs. low current applications

Alan Ritter wrote: I use the NiMH batteries exclusively in my digicam (Nikon 990). It has been my experience with my Garmin GPS II+ that the NiMHs don't last as long in the GPS as regular alkalines, which is just the opposite of the digicam. It may have to do with the respective power supplies and what their minimum Vin requirements are.

Richard Vassar wrote: Battery capacity, especially for alkaline cells, is a function of the current drain from the load. In high current drain applications, e.g. flashlights, CD players, digital cameras, lithium AA cells have a significantly higher mAh capacity than alkaline batteries.

Kevin Craig wrote: Richard, thanks. That squares with my experience using lithiums in FRS radios, headlamps, GPS etc. all high-drain applications.

Rich Feldman wrote: Yeah, what Alan just said about NiMH outlasting alkalines in a digicam but the opposite in radio receivers! A while back I posted an explanation here, with URL's to battery technical data (e.g. under, look for OEM information).

The Mallory charts give the AA size alkaline cell a capacity of about 2800 mAH, but that's at room temperature, under light loading, with end of life at about 1.0 or 0.9 volt. Under similar conditions the NiMH are around 1500 mAH as Alan says. But if you draw over 500 mA, like the Coolpix with monitor on, the alkaline really sucks, and dies after less than 900 mAH. This is where NiMH (and NiCd) excel: the ability to deliver most of their energy at relatively high currents (even the 1 hour rate is no sweat). (By the way, the coolpix is very tolerant of battery voltage variations, in fact draws more current at lower voltage, which implies a switching-mode DC-DC converter).

I don't know how lithium cells stack up, but in the previous thread here, someone gave us a URL to tech data. At low current they outlast alkalines, and much more so at low temperature. Don't know about their fast-discharge performance, but many digicams now come with a starter set of lithium cells. (often each 3-volt cell is packaged to replace a side-by-side pair of AA's).

Paul Wilson wrote: The Lithiums are much better for high current draw as in a photoflash usage wherein the battery has a significant recovery time between flashes and rewinds. Alkalines perform best when subjected to low steady current draw, as in a gps or modern LED headlamp. All the reports I can find about Lithiums having longer life at normal temps are for usage in cameras or other intermittent, high current applications. Can anybody provide reports comparing low current draw between the two different batteries? Real info would be better than the photo people testimonials. If someone has Backpacker from some time last year they compared Lithiums against alkaline's. Dont know about current draw or temperature, but I was told it was a low temperature test.

BTW, I would not consider my LED headlamp as a high current drain device with a alkaline battery life or about 20 hours. My gps has similar low drain characteristics. Even my old halogen lamp was good for 6-8 hours on good old low mAh alkalines.

Steve Eckert wrote: Battery capacity depends STRONGLY on temperature (which most people recognize) but ALSO on current drain (which few are aware of). Some alkaline batteries have a longer life in a clock than sitting on the shelf not providing current at all. The slow discharge keeps them from leaking.

Other batteries appear to discharge completely when used in a bright (high-current) headlamp, but if you take them out for an hour or two they will magically 'recharge' and you can get more use out of them. Sort of like sopping water off the floor only to find that more water seeps out of the soaked walls. That's the kind of battery that would work better in a low-current application.

Those ratings like 3000mAh, mean '3 amp-hours'. That can TECHNICALLY be a 3 amp current provided for 1 hour, or 1 amp provided for 3 hours.... but good documentation requires keeping those two numbers separate. They will NOT be the same. You can't JUST look at the mAh rating. You've got to know whether it was tested with high or low current, intermittent or steady drain, and at what temperature.

Alan Ritter wrote: Steve is quite correct. If you go to the battery manufacturers' WWW sites ( for instance) and look up the technical data on batteries, you will find that alkaline batteries have vastly different energy content depending upon the drain to which they're subjected. By 'vastly', I mean 3:1 or more, getting worse and worse as the drain goes up. Alkalines are also more temperature sensitive than lithium cells.

Part of this has to do with the internal impedance (resistance) of the battery, part to do with the chemistry. That's why alkalines are absolutely worthless in high-drain applications like digital cameras but work great in relatively low-drain applications like LED headlamps, Walkman radios (not CD players), etc.

As usual, it's a matter of matching the tool to the task. I have a couple of small single-LED flashlights that run off 9V batteries. Using them fairly regularly (but briefly) on Scout outings, the original batteries lasted nearly a year. The one that really died would actually burn brighter on the 'low' setting than on 'high' at the very end. The internal resistance of the battery had gone up enough that the loss across it consumed enough power that the LED could not achieve its maximum brightness. I don't know how long the second set will last...they're out of my 'change the battery in the smoke detector every six months' box, but, hey, if I get six months' use out of them, they're free...sort of...

longest-lasting battery is different in moderate vs. low temperature applications

Paul Wilson wrote: For arctic expeditions most use a battery pack for the headlamp that is worn inside the clothing so they work fine at low ambient temps since the batteries do not get cold.

Alan Ritter wrote: My experience with the NiMH batteries has been in moderate temps, down to near freezing, but certainly not winter conditions. They seem to hold up pretty well down to 32F.

Kevin Craig wrote: NiMH's also suffer from the cold; to a lesser extent than alkalines but MUCH more than lithiums. A matter of fractions of ounces, but the Lithum batteries are also noticeably lighter than either alkalines or NiMH's.

even in ideal conditions, capacity varies with battery type

Paul Wilson wrote: I just looked up alkaline capacities and the Eveready's best alkaline is rated at 3135mAh and their new Lithium Photo is listed at 2900mAh. This validates Monty's post. Who should we believe, Eveready or various testimonials? Consumers Reports tested alkaline's and said that the Duracell Ultra is significantly better than the Eveready. The cost at Walmart is 0.95 vs 2.48 each,less for the alkalines when on sale. Lithiums seem to be pretty hard to find in the out of the way places I tend to go. Not many Walmarts or camera shops.

Another observation: The Lithiums at 2900mAh and weigh 0.51 oz, Eveready alkaline 3135mAh, 0.81 oz and Duracell Ultra, 0.95 oz (all per battery). Or 7647mAh/Oz, and 3870mAh/Oz. A huge difference.

Don't confuse [lithium batteries in] this discussion with the [rechargeable] lithium-ion batteries that come in many electronic gadgets these days. They are not the same as the Eveready Photo lithium's.

Alan Ritter wrote: When you buy NiMH batteries, be careful of capacities (printed on the battery). The older Energizer AA NiMHs were only 1200 mAH and my Nikon 990 eats them awfully fast. Radio Shack has 1600 mAH AA cells. The latest Energizers (blue and gold color scheme) are 1600 mAH, but I haven't tried them yet. Thomas has some 1700 mAH AA cells, but they're pricey...

Ed Lulofs wrote: On a per weight basis, [lithium batteries] have 4 times as much energy per gram [as standard alkalines]. So I only use lithium batteries when backpacking. I gave up on my Tikka because AAAs are not available in lithium. I think that lithium [batteries] and LEDs are the most weight efficient and reliable light source.

Craig Smith wrote: The capacity of NiMH batteries has been slowly increasing. The best ones you can buy in most stores now are 1500 or 1600 mA hours. But if you go to the internet or some camera stores, look for batteries branded as either MaHa or Quest. These are available in 1700 and 1800 mA hours for AA size. Quest also makes a very nice charger for them that will charge 2 or 4 AAs or AAAs with either AC or car battery. I highly recommend these products - have used them extensively with both GPS and digital photo gear.

Battery Life (summarized from battery technical info taken from Eveready's website)

Monty Smith wrote:

In prepping for Denali, I wanted to find out how different batteries performed in the cold, both for storage as well as power output. I found much good info at Eveready's website, and the following is a summary of the tables and graphs.


  1. Lithium batteries are by far the best for cold usage. The voltage stays constant as they discharge and they have the lowest temperature storage and usage ranges. They are more expensive, however.
  2. Despite theories to the opposite, storing a battery in the cold will not discharge it, and in fact cold storage is good for batteries. They need to be warmed for proper power output, however.
General notes on all batteries: Definitions: Carbon-zinc Alkaline Silver oxide Lithium Rechargable batteries

Ok. Here is my $.02 on batteries.

Richard Booth wrote:

I have shifted to NiMH for most applications in order to cut down on the disposing of batteries. They work well in cameras, headlamps, gps, etc. Just a personal preference.


NiMH: Lithium:

AA Battery Endurance Testing

Paul Wilson wrote:

We all use AA batteries for our gadgets such as head lamps, GPS receivers, radios and the like. The typical alkaline batteries have been the most popular since they are readily available and can be found discounted at many big box stores. Recently, Eveready came out with new chemistry, 'Lithium/iron Disulfide (Li/FeS2)'. The proper name for this battery is 'Eveready Photo Lithium'. This new battery comes from the store with an initial voltage of 1.775 volts average compared to the Duracell Ultra of 1.61 volts average. This portends that the lithium battery will perform better due to higher potential. Lithium batteries are also well known for their low temperature and long shelf life as well as much higher cost.

In the sport plane field the subject came up as pilots often use the same stuff climbers use. So, one of the electrical experts decided to test a bunch of batteries. I provided him with the extra batteries so low temperature data could be collected. This person Is Bob Nuckolls III. What he did was write software for his laptop and wire up the batteries to allow them to be discharged through a 5 ohm load each to a level of 1.0 and 0.8 volts at room temperature and in his freezer. Let's examine the numerical data in table 1 which resulted from the testing.

Standard alkaline battery comparisons at 20 C:
The Duracell Ultra has the greatest energy at 2.42 watt-hours, but the Dollar General batteries have the lowest cost, $0.12 per battery. So the discount house gives good value but not as long a life compared to the best alkaline battery which is the Duracell Ultra.

Lithium battery comparisons at 20 C:
The lithium battery compared to the Duracell Ultra has 31% more energy and is 120.% $/watt-hour higher in cost. The lithium battery compared to the Dollar General has 52% more energy and is 558% $/watt-hour higher in cost.

Comparisons at -20 C:
The Lithium has 272% more energy than the Duracell and costs 23% $/watt-hour LOWER in cost.

If the temperature is real cold, use lithium instead of Duracell Ultra for lower cost and for longer life. At normal temperatures and long trips select Duracell Ultra. For shorter trips select the cheapest alkaline batteries you can get and change them as required.

Click here for a larger bitmap, or scalable PDF version of this table.

The real numbers from the computer are as follows: The lithium took 30,500 seconds to drop to 0.9 volts at -20 C and it ran 33,680 seconds at room temperature. The Duracell Ultra poops out at 8,800 seconds at -20 C and it runs 31,430 seconds at room temperature.


Battery Life, at Cold Temperatures - overall graph

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Part of the graph above, zoomed in to read brand names:

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Battery Life, at Warm Temperatures

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Part of the graph above, zoomed in to read brand names