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Battery charger pack specs comparison!
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Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Battery charger pack specs comparison! on 01/28/2014 12:20:35 MST Print View

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.


Mike W
(skopeo) - F

Locale: British Columbia
Battery charger pack specs comparison! on 01/28/2014 14:18:35 MST Print View

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.

Amy Lauterbach
(drongobird) - MLife

Locale: San Francisco Bay Area
Battery charger pack specs comparison on 02/07/2014 11:40:19 MST Print View

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.


Edited by drongobird on 02/07/2014 12:01:20 MST.

Steve B
(geokite) - F

Locale: Southern California
Minty Boost on 02/07/2014 16:04:29 MST Print View

You could build a Minty Boost,

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


Edited by geokite on 04/05/2014 19:35:41 MDT.

Scott Hayden
(Spiffyguy) - F
How large? on 02/19/2014 20:16:00 MST Print View

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.

Scott Hayden
(Spiffyguy) - F
E3 or E5 on 02/22/2014 11:17:03 MST Print View

Any thoughts? If not I guess I will go larger with the #5 just to make sure I am covered.

Valerie E
(Wildtowner) - M

Locale: Grand Canyon State
Thank You, Steven D! on 02/22/2014 12:13:28 MST Print View

Great chart -- thank you for sharing all your hard work! It helped me make a decision on which one to buy, so I'm very grateful. :^)

Amy Lauterbach
(drongobird) - MLife

Locale: San Francisco Bay Area
Battery charger pack specs comparison - FluxMob on 04/01/2014 17:41:07 MDT Print View

I received my Fluxmob Bolt.

It's a single unit that has a power adapter and a 3000 mAh Samsung Li-Ion Battery. It's exactly perfect for long hikes in which I'll have occasional access to power. On short trips where I won't recharge during the trip it is not appropriate since I don't need a power adapter on those trips.

Weight = 3.1 oz (85 grams). But since I don't have to carry the iPhone power adapter, the weight penalty for carrying the backup battery is 2.3 oz. (65 grams).

Capacity = 3000 mAh
Output Type = USB 1A
Weight = 2.3 oz, 65 grams [less than actual device, since I've deducted the power adapter I don't need to carry.
Price = $60
Cost per mAh = 2 cents
mAh per gram = 46.1

Unlike the Jackery battery that I own, this one allows pass-through charging, which is a requirement IMO.

Compared to the NewTrent TravelPak, which is also an integrated battery & power adapter:
The Fluxmob has 75% of the capacity
The total weight of Fluxmob is 3.1 oz vs 5.9 oz.

[I have a NewTrent TravelPak (the 4000 mAh version, not the 7000 mAh TravelPak Plus), never used, that sell if anybody wants it. $25 shipped to CONUS. PM me.]

Tim Zen
(asdzxc57) - F

Locale: MI
Re: Re: Battery charger pack specs comparison! on 04/01/2014 18:03:48 MDT Print View

I bought a battery case off ebay for $10 and harvested the batteries from an old lap top (most of them are probably good) Lithium 18650s. Four batteries -- 243 grams. Easy 12,000 mah.


TSA compliant -- I have not had an issue.

Edited by asdzxc57 on 04/01/2014 18:05:57 MDT.

Ian B.

Locale: PNW
Re: Re: Re: Idiot question... on 04/01/2014 19:06:44 MDT Print View

"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."

Hi Jennifer,

By no means am I a "tech type" but from a little reading, it's my understanding that you need to calculate 30% loss in energy transfer.

If my googling is correct, your Delorme SE has a battery capacity of 2450 mAh which needs to be recharged every 100 hrs (Let's just say twice per week) so that's 6370 mAh per week for two charges. If you can get to town before it needs the second charge, then you'd only need 3185mah per week. All at 3.7v.

Don't know which Nook you have but I believe the Simple Touch is roughly 1530 mAh and I personally wouldn't need to charge it more than once per week so there's another 1989 mAh you'll need from your battery bank. Also 3.7v.

If you felt the need to keep your iPhone on in airplane mode for pictures and such, I believe the 5S is roughly 1440 mAh and would only need to be charged once per week so 1872 mAh. Again at 3.7v.

So theoretically you could probably get by with a 10,000 mAh battery bank delivered at 3.7 volts. If you kept your gadgets off except for when you really need to use them, you'd probably be fine with much less.

I know nothing about backpacking solar panels and barely more than that about larger systems. It's my understanding that you'll want one with a charge controller built into it or there's the possibility that it'll suck juice out of your gadget in low light situations. I'll let someone smarter than me confirm if this is correct or if I'm lost in space on this one.

I believe Buck used a solar charger on one of his adventures so you might want to PM him on his set up.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: Re: Idiot question... on 04/02/2014 01:02:47 MDT Print View

Solar charge controllers do different things, depending on the model.

In general, they control the solar charging to the battery. What does that mean?

If the battery already has a high voltage (high state of charge), then the solar panel is cut off. That way, the battery is not subjected to overcharging which would shorten its life. Plus, the battery is cut off from reverse current going into the solar panel, which would be wasted.

If the battery already has a low voltage (depleted), then the solar panel can charge the battery, perhaps unless the battery is completely too far gone. The charge current is typically controlled to be roughly correct for that capacity of battery.

So, the charge controller is constantly monitoring the battery voltage and the solar panel voltage, and it keeps trying to do the right thing.


Derek M.
(dmusashe) - MLife

Locale: Pacific Northwest
Why wouldn't this work? on 04/05/2014 15:34:17 MDT Print View

After reading through this thread, it strikes me that my Eneloop XX NiMH batteries, at least on face value, hold a lot of charge at a reported value of 2500mAh per AA battery.

So four of these batteries would be the equivalent of a 10,000mAh Li ion battery pack, at least in terms of capacity? Am I missing something here?

Also, I have read that a typical iPhone can hold about a 1420mAh charge. This seems unreal to me, that my phone holds less than a high-capacity AA battery's worth of charge. Is this all right?

If it is right, then why aren't there more battery banks out there that simply hold multiple high-capacity AA batteries, like the one Tim Zen made above?

If this works, then it seems like the ideal system would be one where the battery pack itself can be directly plugged into the wall (similar to the NewTrent TravelPack Plus), thereby acting as a AA wall charger, but there would also be one or more 5V USB oulet ports where you could transfer the stored charge to your phone/gadgets.

Am I missing something critical here? I must be.

It seems that a system like this would combine many systems into one: phone charger, battery bank, AA battery charger, and AA battery storage for other AA-based systems, such as headlamps.

So you could bring a system like this and not have to take: a separate phone charger, a AA battery charger, or standalone extra AA batteries.

Again, what am I missing? This seems like it would be the ideal system for me on paper for multi-week hikes with town resupplies...

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Why wouldn't this work? on 04/05/2014 16:15:38 MDT Print View

2200mAh, 5 Volt, 0.8 amp, 2.7 oz, USB output, $10, I think it's lithium, cheap shit from China but I've been using one for a while no problem

Eneloop that I have - 1.1 oz, 1.2 V, 2400mAh - plus you need some stuff to regulate and convert to USB plug

4 Eneloops would be only 4.8V so you'de need 5 of them = 5.5 oz

Edited by retiredjerry on 04/05/2014 16:36:19 MDT.

Glenn S

Locale: Snowhere, MN
Re: Why wouldn't this work? on 04/05/2014 16:23:35 MDT Print View

Eneloops are 1.2v x 2500mAh = 3000 watts x 4 batteries = 12,000 total watts of energy.

Li-ion are roughly 3.6v x 10,000 mAh (in the example) = 36,000 total watts of energy, or, 3x as much juice as 4 eneloop maxis.

Volts x amps = watts.
Watts = apples to apples comparisons

Your idea of an AA batt charger that can be charged from USB via the wall, solar, auto, etc., while also being able to be used as a battery bank to charge other devices via a seperate USB output, is what Goal Zero's Guide 10 is. The problem I have with it, is it doesn't charge each of the 4 batteries independently, so mixing dead cells with good ones produces poor performance. At least that's beem my experience.

Edited by Glenn64 on 04/05/2014 16:35:47 MDT.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: Why wouldn't this work? on 04/05/2014 17:32:43 MDT Print View missed a "milli" or two in there ....

Rex Sanders
(Rex) - M

Locale: Central California Coast
Re: Re: Why wouldn't this work? on 04/05/2014 17:35:23 MDT Print View

Eneloops are 1.2v x 2500mAh = 3000 watts x 4 batteries = 12,000 total watts of energy.

Li-ion are roughly 3.6v x 10,000 mAh (in the example) = 36,000 total watts of energy, or, 3x as much juice as 4 eneloop maxis.

Volts x amps = watts.

Best to get all the units correct:

1.2 volts x 2,500 milliamp-hours = 3,000 milliwatt-hours (mWh) x 4 batteries = 12,000 mWh of energy, or 12 Watt-hours (Wh).

3.6 volts x 10,000 milliamp-hours = 36,000 mWh, or 36 Wh, still three times as much as four Eneloops.

Watt-hours = apples to apples comparisons for battery storage.

-- Rex

Edited by Rex on 04/05/2014 17:36:30 MDT.

Glenn S

Locale: Snowhere, MN
Re: Re: Re: Why wouldn't this work? on 04/05/2014 19:06:45 MDT Print View

Ah, guilty as charged for sloppy work. Anyway you slice it though, whether it's kilo, mili, or plain ol' run of the mill regular watts, it's still watts to the rescue! :)

Edited by Glenn64 on 04/05/2014 19:08:55 MDT.

Steve B
(geokite) - F

Locale: Southern California
Thanks on 04/05/2014 19:41:11 MDT Print View

Been thinking of a portable power source for USB items for a while, just purchased the NewTrent TravelPak Plus from Rakuten for $22. Seems like a good deal, and way more capacity than that Mintyburst I made.


Troy Childs
(tchilds) - F
22mm/26.2mm batteries on the way too? on 04/05/2014 20:24:26 MDT Print View

To make choices even more involved, don't forget there is always the option of the 22mm/26.2mm successor to the 18mm (18650) that we all love so much.

The safe chemistry IMR 22mm/26.2mm batteries are starting around 4000mah with a manufacturer rated sustained draw of over 60 amp. This means you can charge them around 10amp...

As soon as an ICR 22mm/26.2mm comes down in price I'll likely be ditching my old school lithium polymer batteries for the newer hybrid chemistry. Having a battery that charges in 15 minutes in town and packs 7000mah is pretty slick.

Its getting to the point where all we'll need is to hook up to an alternator with lithium ion batteries pretty soon (crazy sounding now but by end of year will be safe I'm sure).

Its getting to a point where running lower draw cells in series isn't going to even be necessary what so ever anymore. Gotta love li ion development. Gotta hate the trash its making to get to the goal.

Most of us have the junked electronics laying around to gut and build our own 5v regulator for micro USB charging purposes. I really think I'm going to get into the new 22mm/26.2mm cells and ditch my bricks very soon. I urge you all to consider DIY solutions. The circuits are so simple a third grader could build them. These consumer driven solutions are really using such out dated cells now, (from last year) , that they aren't even worth buying!

Edited by tchilds on 04/05/2014 20:58:04 MDT.

Troy Childs
(tchilds) - F
26mm even? on 04/05/2014 21:03:03 MDT Print View

Brand TangsFire
Type Rechargeable Li - lithium battery
Capacity 6800mAh
Voltage 3.6 - 4.2Vv
Dimensions 7 x 2.5cm / 2.76" x 0.98" (L x Dia)
Number of Charge Cycles 10000times
Color Blue
Weight 3.33oz / 94.5g
Model 26650
Plus Board Yes (2.78V - 4.25V)

Package Includes

1 x TangsFire 26650 6800mAh 3.6 - 4.2V Lithium Battery with Board Blue

And that ain't even a name brand like sony, or panasonic... I'm still waiting for the Sony or panasonic version of this format to come out in a "protected high capacity" format.

I've got a couple of these batteries and my icharger is actually loading around 7400mah on them at 4.25v, versus the advertised 6800mah. I think within a few months maybe there will be some 10,000mah for around 3 ounces.

Edited by tchilds on 04/05/2014 21:14:24 MDT.