Jan 4, 2014 at 10:46 pm #1311787
I wanted to find the smartest choice so I compiled a list of specs. It was annoying as hell to convert it from a spreadsheet into an image and it didn't come out that great. I suggest you save the original file and then zoom in on your computer or phone. It'd be nice to have it on the web and sortable but I'm not going to put in the time.
I highlighted the best deals. It's unclear which weights include charger cable. A short micro-USB to USB weighs around an ounce or less. Most of them are USB output, a few have DC. This isn't totally complete. I left out ones that I couldn't find weights for and also bad deals. Let me know if I'm missing any.
If you have questions about how any of this works, check this out: http://www.rei.com/learn/expert-advice/solar-chargers-portable-power.html
NOTE: After doing a little more research on 2000mAh IOGEAR, I think the weight is >2oz and the specs quoted were wrong.
Also, it looks like Anker has great customer service so that might sway your decision.Jan 6, 2014 at 12:11 pm #2060908
Bump! Hopefully someone, anyone can get some use out of this!Jan 6, 2014 at 12:30 pm #2060919
Wow that's a lot of research. Nice effort.
It would be great to have a power pack that charges from the wall (rather than USB) so on a thru hike I could use the power pack to replenish a device in the field, but also use the power pack to charge the device at a Starbucks in town (ie. wall plug in -> power pack -> usb cord -> device). If one could do that and leave the regular wall charger at home then it would be more effective.Jan 6, 2014 at 12:48 pm #2060925
That's why I picked my USB charger by NewTrent, a TravelPak Plus. You can get bigger capacities (it is "only" 7000mah), etc. but I like the form factor, pop out AC prongs, and pass-through charging (so it charges itself in an outlet while also charging 1-2 items plugged into it).
Used it on a long trip recently to keep my headlamp (Petzl Core), GPS watch, Iphone, Ipod shuffle, etc. charged and it worked great. Topped it up every 3-4 days when I got to a power outlet, and it handled all my charging needs.Jan 6, 2014 at 2:29 pm #2060958
@jasongLocale: iceberg lake
nice work! thanksJan 6, 2014 at 3:28 pm #2060971
Anker Astro 3E 10000 mAh
Amazon Prime Price: $39.99
Listed Weight: 8.6oz/243g (I can give a more precise weight when I get home if you want)
Dual 3A output, 1 android 1 apple
Cost per mAh: .39¢Jan 6, 2014 at 3:43 pm #2060975
@andysLocale: Midwest USA
I can attest to Anker's customer service, if not quality. My 12-year-old bought an Anker gaming mouse off Amazon which stopped working (not 100%) after a few months. With little help from me, he was able to contact their warranty department, and got a new one within a week without any hassle.Jan 6, 2014 at 4:31 pm #2060994
I got an email from Patriot (Fuel+) confirming that their weights include the cable. I'm going to assume the rest of the weights, for the most part, also include the cable.
The Travelpaks are definitely cool since they eliminate that redundancy, but they're heavy. The Travelpak+ (7000mAh) is 8oz, the Travelpak is 6oz, and the Chargepak is 6.6oz.
For the additional weight (unsure.. ~1oz?) of carrying a USB wall charger, you get more mAh: http://www.firefold.com/usb-wall-charger-white
eg, if you carry 3 GearPower 2000s and a USB wall charger, that's 6000mAh for 4oz. Or the PocketCell Duo and charger– 6800mAh for 5.7oz.
It's too bad they don't make more of these with plugs on them!
Benjamin- thanks for that addition. Let us know if the listed weight includes cable or not.Jan 6, 2014 at 5:52 pm #2061026
Mine comes in on the scale as 8.3750oz/238g. This is battery only weight and does not include cable(I don't use the original) or storage bag.Jan 6, 2014 at 6:16 pm #2061038
That NewTrent TravelPak Plus is really cool. I'll keep it in mind.Jan 27, 2014 at 11:46 am #2066829
About 6 months ago I got the NewTrent PowerPak Xtreme (http://www.newtrent.com/store/iphone-external-battery-iphone-portable-battery/powerpakxtreme.html). Lil heavier (11oz) but this is solid + dependable. I charged it once from the wall (approx 8 hours) and after that used it to recharge my iPhone 5 about 5x – and, it held that initial charge for about 4 months! Especially for heading into the wild this is excellent gear and dependable. I can use GPS a little more freely without nervously rationing horizontal bars. Surveying the current crop of manufactured goods, there doesn't seem to be much else I would trust for a multi-day trip; the solar tech seems underwhelming without MYOG mods/builds. Oh yeah, the Xtreme has mil spec features for shock+water so there's less worry about trail wear. Maybe a lil heavy for UL purists, but this is dependable FWIW.Jan 27, 2014 at 6:40 pm #2067003
just found this, 3000mah and a wall charger at 3.1 oz and $60Jan 28, 2014 at 4:53 am #2067098
@jenmitolLocale: In my dreams....
Don't laugh…but I'm pretty tech stupid. This is my understanding of said products:
These are rechargeable battery packs that one carries in lieu of a solar charger to recharge one's devices, correct? So instead of an as yet unreliable solar charger, I carry this batter pack around, can recharge things maybe 2-5 times, then I need to recharge the recharger????
So on a thru hike, this would work well as you could top off the battery pack AND the devices, but as the devices drain in the field you can keep topping them off until this battery pack dies. And the desire for a wall charger is to hook what to the wall??
Sorry, but I've been looking at solar chargers really closely and with great disappointment, but I've started to read about these…….
Can you school a girl please??Jan 28, 2014 at 5:38 am #2067103
Jennifer, I just wrote something to introduce the basics of external batteries including some purchasing tips for hikers. You may find it useful.
http://www.sparkyhikes.com/2014/01/choosing-external-battery/Jan 28, 2014 at 6:53 am #2067120
Philip, Very helpful article. Thanks!Jan 28, 2014 at 7:01 am #2067123
Choosing an External Battery
January 23, 2014
I recently investigated the external battery market. As always, a backpacker needs to become a minor expert in a subject in order to see through the marketing fluff and make a wise purchasing decision so I thought it might be useful to pass on some of my new-found knowledge.
What Is An External Battery?
Charging a smartphone
Physically an unremarkable metal and plastic oblong probably about the size of a thick smartphone (the thicker ones probably have more capacity, i.e. store more juice) or some smaller ones are lipstick shaped. It is basically a big battery which you can recharge hundreds of times from a wall charger or via a USB cable from, say, a laptop or personal computer.
It stores the electricity (which I shall call ‘juice’) for several months, losing only a little over time, and when you need to recharge one of your devices (ebook reader, phone, tablet, camera, GPS unit, headlamp, etc.) you connect it with an appropriate cable (you often have to supply your own, such as the one that came with your device) and it charges your device. It may or may not do this very quickly and it may or may not charge it all the way up and it may or may not be able to repeat this process depending on the respective capacities of the device and the battery.
It is worth noting that they are useful for many, but not all, mobile devices. A colleague just bought a Toshiba Excite tablet and, unlike say a Google Nexus or Apple iPad, it requires a traditional laptop-like ‘brick’ transformer outputting 3 amps and therefore isn’t really ‘portable’ despite its form factor and ‘tablet’ name. Such devices are beyond the purview of the external batteries reviewed here.
So, if you carry an external battery you will be able to recharge your compatible devices ‘in the field’, both metaphorically and literally, i.e. away from a wall charger. This makes them potentially useful to backpackers who wish to carry electronic devices (phones, GPS units and personal locator beacons in particular) that will otherwise run out of power too soon. Day hikers probably don’t need to carry one.
What Do I Need To Know In Advance?
You have to be clear in advance which devices you want to charge with this battery, what power input port each has (all devices have only one power input port ), what the input rating for that port is (in watts) and what the capacity of each of these devices is (in “milliamp hours”). You should also check the input voltage for your device is around the output voltage of the external battery, usually 5V.
And of course you have to decide yourself how many times you want to be able to recharge your device – is an emergency 20% top-up sufficient, do you want to recharge it fully twice, or whatever you want. Obviously, the more spare juice you want the bigger a battery you will have to carry.
Aside: some devices quote their capacity as ‘watt hours’ instead of milliamp hours. To convert watt hours into milliamp hours you divide the battery watt hours by the battery voltage and then multiply by 1000. In practice it is easier to just Google “‘my device name’ battery in mah” to get the answer. E.g. the iPad Air (2013 version) is only listed as 32.4WH on Apple.com but Wikipedia soon tells you that it’s about 8800mAh.
What Are the Key Features of the External Battery?
Capacity – aka how much juice it can store. Luckily this is expressed in the same way for all batteries and appears to be a reliable and trustworthy value. It is ‘milliamp hours’ or mAh and the number is often found in the product name itself but is always found in the product description or specifications list (‘specs’). A very small value is 1000, a medium size is 4000-5000 and a large one is, well, bigger than that.
Weight – this is always a key spec to consider for all items when backpacking.
How many output ports – batteries always come with at least 1 output port but some come with 2, 4 or even more. Decide how many you need. Having an extra one or two you won’t use is not a problem other than the extra weight and space they will have taken up.
What kind of output port(s) does it have? Micro-USB, full-size USB, Apple 30-pin or Lightning? Typically a 2-port unit has 0 or 1 micro-USB ports and 1 or 2 full-size USBs but check. To use an Apple device from a full-size USB port you just need to use the cable that came with your Apple device. While you can buy an Apple micro-USB converter it probably isn’t worth it; it’s easier to get a battery with a full-size USB.
Input rating – how much charge it can take into itself dictates how quickly the battery itself recharges. This is a very important feature that is little-discussed and can be hard to find but will impact you enormously when out backpacking with very limited access to wall sockets for recharging.
Output rating(s) – how much charge it can give out to your devices. What charge can each output port give out? How is that charge affected when more than one device is plugged in (is it shared)?
You might think that ‘ruggedness’ is a key feature a backpacker looks for but actually this feature is so rare as to render a shortlist self-defining and the battery would be so heavy that it makes more sense to pop a battery in a light waterproof bag and just be careful not to drop it.
Note: all external batteries supply only a fraction of their rated capacity to the charging device due to loss to heat and other inefficiencies. Typically this runs from 70% to 80% so before purchase you have to accept that a 5000 mAh battery may only supply 4000 mAh of juice at best.
Do You Actually Need One?
So now we know what is going on in with batteries in general we can decide if they are right for me. If I take a 1470mAh Kindle for book reading and an 1420mAh iPhone 4 for I would probably only need the battery for the phone since the Kindle lasts a long time between charges and is not at all vital to keep charged – whenever I run across a usable power outlet every week or two, that will be fine.
Some devices allow you to change the internal battery. Cameras and some cellphones for example. You can maybe even purchase such a replacement battery with a bigger capacity than the manufacturer supplied one making it a real double-win for you. In this instance you may elect to simply take a spare battery for that device only, rather than use a generic external battery, or at least use that idea to supplement your battery needs. For example, I will take two camera batteries because I can get a 1500mAh battery for my Olympus TG-630 for £5 to supplement the Olympus-supplied 925mAh one. Together they ought to last a week or two.
That iPhone 4 has a 1420mAh capacity. A battery that weighs about the same as the phone (136g) will be about 5000mAh capaity so will supply about 2.8 full charges (5000*0.80 efficiency/1420). That’s pretty useful. A fully-charged iPhone and battery will give me at least 3.8 uses of the phone.
One tip I picked up is that many devices ‘fast-charge’ up to 80% of its full capacity and then slow- or trickle-charges up to 100%. This means that it is more time-efficient to only recharge to 80% each time as the final 20% could take almost as long. Check your own device before setting off and see if this true for it.
And another thing: there is a long-held myth that batteries such as these or the battery in your device must be fully drained before each recharge, and that each recharge must be to 100% each time, or else the battery will develop a ‘memory effect’ such that it doesn’t store as much juice as when you first bought it. This is not true with modern lithium-ion batteries (“li-ion”). Check your manual. It may recommend the occasional such cycle, in which case follow those instructions, but nothing more is necessary.
My core needs were as following:
I am taking an iPhone 5 and a Kindle The iPhone has a capacity of 1440mAh, accept 1 Watt input and uses an Apple Lightning port. Apple supply a USB-Lightning cable with the phone so that can be used. The Kindle is about 1300mAh, uses micro-USB and accepts 500 ma (milliamps) of input.
My shortlist criteria therefore were:
A 4000-5000 mAh battery with a full-size USB output port capable of supplying at least 1 amp. This is a pretty standard requirement.
I want it to be as light as possible (of course).
One output port. Nothing wrong with 2 but I only need 1 as I have no requirement to charge my phone and Kindle simultaneously.
I want it charge as quickly as possible so I want the input rating to be as high as possible (2 amp or more). The vast majority of batteries only take 1 amp so will charge twice as slowly as one that takes 2 amps. This was a big filter that cut down the shortlist to a very short list.
Good reputation. I didn’t want a battery direct from the Far East with no trading history, no US- or European-based company to take responsibility. I wanted to be able to rely on the unit working in the backcountry, I wouldn’t have the chance to ring suppliers, return the product, get a replacement, etc. It had to work first time and best way to ensure that is to stay away from the ‘bleeding edge’.
Optional: 2 amp or greater output. While an iPhone and Kindle would not need it, many people report an iPhone charges slightly quicker when the charger exceeds the standard 1 amp and I also wanted the battery to work for the tablets we have at home so it had more use outside of the AT hike. This was a minor decision criterion therefore.Jan 28, 2014 at 9:20 am #2067170
@jenmitolLocale: In my dreams....
So you tech types…considering the state of the market at this point, it seems like a battery pack may be the best for thru hiking at this point, yes? I need a rare Nook charge, a more frequent Delorme SE and an occasional iPhone top off.
During my JMT I wished I could have charged the delorme and the nook (accidentally drained the reader in my pack one day…wanted a charge SO bad!! But a borrowed solar charge gave me a mere 3% charge that lasted just a day. But I digress). I'd like to be able to have the delorme drop more frequent breadcrumbs (for later viewing, not necessarily for safety…).
I'm doing a thru hike of something this August/September (CT or the JMT again) and was looking at solar chargers, but I'm so unimpressed and they're not cheap. Maybe the battery pack is the way to go.
Thanks so much for the article!!!Jan 28, 2014 at 10:00 am #2067183
> It'd be nice to have it on the web and sortable but I'm not going to put in the time.
You could pay someone $20 bucks on Craigslist to put it into a google spreadsheet .Jan 28, 2014 at 10:03 am #2067187
The main issue with this is that you're losing efficiency moving power from one battery to another battery.
If you are stuck with your iphone or a camera that doesn't have external batteries then … you're stuck.
However, it makes much more sense in my book to just buy external batteries for your device.
I have the Samsung Galaxy S3 and it rocks. I have about 6 external batteries and I can charge them up and get about 2 weeks of power from it. This includes taking liberal videos, pictures, etc.
Anything more than 2 weeks implies you should probably be using a solar charger.Jan 28, 2014 at 10:04 am #2067188
@dwambaughLocale: Pacific Northwest
Solar is unlimited, but a weak current and give a slow charge and you need good direct sunlight for best output. I hike in deep dark forests in a region with lots of rain and overcast, so they aren't a very good option for me. If youre in deserts or above treeline, you might get good use from one. There's whole tangent to go on there. It struck me that forest fire lookouts would be the perfect place for a big solar panel.
The good quality battery packs are reliable and fast and easy to use. They have good everyday and general travel uses too. We keep one in the car so it is a universal backup and there for hikes as needed. I have a cigarette lighter adapter so I can charge it in the car.
I like the known value and control with the battery packs. Some have indicator lights to give you a rough idea of the state of the charge and how much remains. They can be shared, which drops the weight value a bit.
If I were through hiking, the ones with a charger built in are appealing, with less stuff to haul, lose or break. I would definitely want the option of charging the battey pack and my devices at the same time.
From there I think it is a choice of a small light CYA/backup that will give a single or partial charge vs a larger heavier unit that will give several full charges.
Another hiking option is a weatherproof case with a battery pack built in. Most have a switch, so you only use the extra battery deliberately, as needed.
I wish Apple would build a phone with replaceable batteries. My old phones worked well that way and carrying a couple spares was easy. Some designs would allow using a larger battery that was even better.Jan 28, 2014 at 11:20 am #2067210
@b-g-2-2Locale: Silicon Valley
There is another battery option. It should appeal to the ultralightweight hiker, but not to others.
That is to build an external battery pack that uses lithium primary batteries. Simple battery holders can be placed inside a plastic bag. These are "One-Shot" batteries, but they get you a very high amount of power for the weight. Besides, lithium primary batteries can supply a tremendous current, even at cold temperatures.
If you are trying to charge a device at 5V, then four lithium primary batteries in series will provide 6.8V, so a zener diode might be helpful for protection of the device.
The cheap version of this is the same, except that it uses alkaline batteries.
–B.G.–Jan 28, 2014 at 1:18 pm #2067248
@skopeoLocale: British Columbia
Like Bob mentioned, I like to be able to carry spare batteries for my charger so I bought a SolarFocus charger that uses AA batteries for its power source. I don't use the recharbgeables that came with it, they didn't work very well but with Lithium AA's it's been good. It also has an add-on solar piece as well that sells separately but I wasn't interested in that. With any of the battery chargers, I find it's most efficient to only top up to 50%… the last 30% or so seems to drain the batteries exceptionally fast, so I don't bother trying for a 100% top up.Feb 7, 2014 at 10:40 am #2070864
@drongobirdLocale: San Francisco Bay Area
Thanks Steven for the spreadsheet! (FWIW, it's easy to put your spreadsheet into a dropbox folder and share the link so people can view it that way.)
Thanks to Sparky for the link to his article.
And thanks to Tyler for link to FluxMob Bolt – I just ordered one.
I've been using a Jackery and mostly happy with it. But it doesn't allow pass-through charging, so with only one power adapter I have to choose between charging the battery and charging the phone when I stop for 15 minutes at a grocery store. So I've been on the hunt for a small light battery that has pass-through charging. The FluxMob looks just perfect for thru-hikes. For backcountry hikes the FluxMob product makes no sense, since you don't need a power adapter and you don't do any recharging during the hike – for those purposes I've been happy with the Jackery (or something similar from Steven's list).
The Jackery 2600mAh + its input charging cable + iPhone power adapter = 3.8 oz.
The FluxMob is advertised to be 3.1 oz and 3000mAh. 15% more battery capacity, pass-through charging, and 0.7 oz lighter than my current solution! I like it already.
AmyFeb 7, 2014 at 3:04 pm #2070967
@geokiteLocale: Southern California
You could build a Minty Boost, http://www.ladyada.net/make/mintyboost/
Made one recently, I'll edit this post with the weight when I get home. Might be worth while for a thru hike, figure it depends on how much charging you will be doing.
EDIT: Weight with 2 lithium AA batteries is 2.9oz
SteveFeb 19, 2014 at 7:16 pm #2075277
I have a little 2 oz battery pack with a solar panel attached. Not that great. Planning a 10 day hike and will need a larger one. My camera, Kodak ZX5, has integrated battery so I have to charge it. I also take a lot of video for youtube, am I a dork, so plan on recharging probably every 2 days. Lucky for me it has the same USB as my phone. I think the battery is 1050 mah. So how big do I need to get to get about 5 -7 charges? Was looking at the Anker Astro e5 at 15000 mah for 11.2 oz. it is 50 bucks. Heavy too but it is what it is. The E3 is 10000 mah at 8.5 oz. Little lighter.
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