The point has been well made and is now taken for granted that all our electronic devices should share a common battery size, with AAs being the most referenced. The argument is typically "I can take the batteries from my GPS and use them in my headlamp," or "My spares can be used in either device," or "AA batteries are available everywhere."

How often does having a common battery type actually get played out with these arguments? Has anyone ever taken the batteries from their headlamp and placed them in their GPS? Or conversely, do members here fly in the face of the common battery wisdom, and use a mix of two our more cell sizes (like me)?

For all except the thru-hikers, I suspect the need for a common battery type is a myth, and like the "need" for heavy packs and 12" waffle-stompers, reality is far from need. I believe it's a myth because:

--We're usually knowledgeable enough about the use of our devices so we know what our battery needs will be, and pack accordingly. Often a set of batteries will last far longer than a typical 2-5 day adventure, and we know which device needs spares and which don't.
--Some electronic devices can be satisfied with lightweight backups or modified behaviors when batteries die: map and compass, asleep before darkness, Photon on necklace, etc.
--Devices that use AA batteries are typically bigger and heavier: a Steripen using CR123A vs. one that uses AAs, headlamps, flashlights, GPS, etc. By seeking lighter items (AA vs. CR123A vs. AAA), we wind up with asymmetrical battery types anyway. I know half of us will race out and buy the first AAA-powered Steripen if it's ever produced.

There's also financial motivation: money spent leveling the battery-type field could be put to better use, as many electronic devices are $50+, and that could be used for a lighter quilt, or tarp, etc. We happily drag our AA GPS, AAA headlamp, and CR123A Steripen into the woods, since we'd rather use that money elsewhere in our kit.

I have an 1X AA headlamp, a 2X AA GPS*, a 2X CR123A Steripen, and a 1X AAA flashlight (for trail markers). Three different battery types! Each does it's job very well, or is fairly new, or would cost a lot to upgrade. Each device has been tested in my "lab" and in the field for battery life, so I have a pretty good idea how long I can go before replacement. For 2 night trips, I don't carry any spares, but it's comfortable knowing that I can last 5 days if necessary.

So how many different battery types are you toting around?


*Lately, I've been using my phone in a waterproof case. Cell phone batteries are a lot cheaper than a new GPS, and I have to carry my phone anyway. But I guess the phone batteries are just another battery type to carry!

I like things that use AA not so much because I want everything to use the same type but because I've got a boatload of rechargeable AAs. At home I use them in remotes, flashes, toothbrushes, game controllers, etc so I know I've got plenty. I don't have anything that runs on 123's and only a couple of AAA rechargeables. So for me its more about simplicity at home rather than in the field. I only have to worry about stocking one or two types of battery rather than three or four.

When I hike I carry a 1x AA headlamp, a Photon light, and sometimes a 2x AA GPS. Plus that damn D300 but its battery will last well over 600 shots so one is normally enough. I do have a battery grip that will power the camera with 6x AA batteries though :D

Adam

Batteries are different for a purpose. AA size offers high milliampere hours. AAA offers less, but the package is much smaller and lighter. Lithium primary cells offer great shelf life, high milliampere hours, high peak current, and great cold temperature operation, but the cost is high. Rechargeables are great, since you can recharge them, but in many cases they won't provide the voltage and amperage quite so consistently as alkaline or lithium.

As long as the device designer chose the correct battery type for the purpose, that is good by me. I generally do not carry any spares, but I test the state of each battery before I leave home.

--B.G.--

There is some good news here.
Because of power requirements and available size (inside the device) I am pretty confident that we will never see a common battery size , however there is a solution.
That is a :common way to charge them and that appears to be the USB standard.
We see more gadgets that can charge directly from USB so all you need is one USB "bank" (battery with USB in and out) and a plug adaptor for each device and you are in business.

I have a GPS with 2 AA batteries. They last for about 24 hours which is enough for any trip, yet I always carry a spare set but never need them. Except, after a year or two, the lifetime of the batteries shortens so maybe I'll use the spares. Especially if it's cold. I never go more than about 50 miles in 5 nights which I do in less than 24 hours of hiking.

I now have a radio with 2 AA batteries. They're good for 100 hours. That's good for 5 night trip, because I don't always have it on. Might need the spares, but it's not critical, if the batteries ran out I'de just quit listening.

Hmmm... I think maybe one spare set of 2 AA would actually work.

I have a 3 AAA LED headlamp, but they last for about a year, and towards the end they gradually get weaker so I can tell during a trip that it's time to replace, no need for spares. Plus I have a Photon button LED light as a spare.

I use the new Eneloop AA 2400 mAH

And Lithium AAA for LED headlamp

Edited by retiredjerry on 01/30/2013 18:31:13 MST.

I never saw it as a need. A preference yes. I don't think a preferenc can be a myth.

I've definitely moved batteries from one device to another. Not so much while backpacking, but caving can involve multiple lights, cameras, flashes, GPS, and sometimes instruments (water quality, CO2/O2).

I have a strong preference for AAs. Somewhat for the exchangeability. But also, I can buy a 40-battery brick at Costco for pretty cheap. And lithium AAs are about the same cost as lithium AAAs, so the cost per joule is a lot less.

Even at home, I try to limit the different types of batteries -- and use either AA or AAA rechargeable batteries as much as possible. I like the idea of recharging more than throwing away. But in the field, I will use headlights powered by coin-cell type batteries just because they are so much lighter and more compact.

Having common batteries may not be a necessity, but I've found it useful. For example, my camera uses AA as does my GPS. I've found that I can run my GPS for a considerable time on batteries that are already too weak for my camera. I've also got a AA charger for my solar charger so I can charge up spare batteries and have them ready for either device.

The usefulness of having a common battery type may be a myth to one person and not for another.

I also have swapped batteries between devices...common ones being GPS and headlamp. And I've done it both ways...my problem is that on my quick 1-2 day weekend trips I frequently forget to check if I have any spares in my ditty bag...and I really only use the GPS on those trips for recording purposes (short trips, don't carry much consumable stuff, have room/weight for the little device...it can be fun to play with if I'm so inclined). So...when that headlamp is too dim (oh crap! I forgot to add the new AAs in there again) I just rob from the GPS because honestly, I don't really need it...

I'm much better when planning for bigger, "real" trips. These quick weekend getaways I kind of just grab my pack and go. Not too much thought sometimes. Of course, I've forgotten more than batteries before...stove fuel? So needs stove fuel??

"For all except the thru-hikers, I suspect the need for a common battery type is a myth"

Even there, I think. The problem is that when you're selecting gear, you're trying to optimize for several different criteria at once, and it can be difficult to decide what to prioritize among factors such as cost, durability, functionality, weight, even size. The more factors you add into the mix, the more likely that you have to give ground on some of them. I see "uses a particular battery type" as yet another factor to try to optimize if you're carrying multiple battery-operated devices.

Some choices to limit such devices helps --- smart-phone as a multi-purpose device, for example, but there you're already blown out of the "one battery to rule them all" approach. Chemicals rather than a steripen. That sort of thing.

I do think that the smartphone as multi-function device is what put the nail in this one for me --- that plus comparing the weight of a Petzl e+lite to other headlamp options. I have had a couple of situations where carrying a spare set of lithium AA's made sense in the context of being useful for a couple of different devices I was carrying, but it's been rare.

I like to have my important devices on the same batteries for convenience, CYA and weight savings in about that order. My GPS uses two AA's and my headlamp and flashlight us one each. My radio uses one AAA, but if that dies it is just an annoyance, but not a show-stopper; lighting is my main concern. So one or two spare AA's will take care of any critical needs. For an overnight or 3-day and fresh batteries all around I could go without spares, knowing that I have the cross-compatibility.

I would class this concern as a refinement and a move to simplifying my kit-- less to haul, keep track of and maintain. Once you get the major items tweaked to your weight and performance needs, there are all the little bits to work on. I'm thinking of things like decanting all your hygiene items to small containers, minimizing stuff sacks, safety essentials, tools, etc. Batteries are one of those little tweaks. None are really significant on their own, but they can add up and you can shave a pound pretty quick.

Since my headlamp that I like uses AAA's, I searched for an MP3 player for audio books that takes AAA's. Ipods are no good for me because the battery does not last long enough for a week-long ski trip.

Yes, battery commonality is "nice".

OTOH, like Simon, the OP, I use 2 AA for my Garmin Colorado GPS, 4 coin batteries for my tiny Princeton Tec Scout headlamp and 2 CR-123 batteries for my Steripen Adventurer. So battery commonality is out the window for me too.

...and then the same number of spares - all lithium, of course. Wouldnt' want to carry too much weight with those heavy alkalines, ya know.
That would be SO 20th century. :O)