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device chargers that use lithium AA's
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Adam Berg
(AdamMBerg) - F - M
device chargers that use lithium AA's on 03/27/2014 12:28:14 MDT Print View

I have very little technical knowledge about electronics and batteries, how they charge, etc. Please educate me. Apologies for the long post.

I have seen discussions of fairly lightweight AA device chargers in a few threads. Specifically, these two:

Energizer, 45g for charger, runs off of 3 AA's (possibly discontinued?):

Miller, 32g for charger, runs off of one AA:

What are the pro's and con's of these two? For example, I'm reading in the inReach SE thread that the Miller has the amperage to charge the inReach but the Energizer one does not. Will either work with pretty much any smartphone (if you have the right cable or adapter)? What about other devices that charge from USB but have different requirements, like headlamps, iPads, Kindles, Steripens, and so on?

What is the difference between the kinds of lithium AA's that these two chargers can use to top off electronic devices? Weight? Capacity? Reliability? Rechargeability?

The Miller one can charge rechargeable batteries in addition to using those batteries to charge other devices. How do the batteries you can charge with this Miller device compare to the Energizer lithium AA's you commonly see at RadioShack (other than the fact that one is rechargeable and one is not)?

Are there better chargers out there in this same weight range?

What are the advantages/disadvantages of these chargers that run off of lithium AA's compared to external batteries that you charge from a wall socket (other than weight differences, and the use of AA batteries vs. AC charging)? Obviously depending on how long you'll be away from AC, the decision might be fairly obvious unless you want to carry solar panels. But what considerations are there other than that?

Right now I have the Energizer charger and a Lightning adapter to charge my iPhone with Energizer Ultimate Lithium AA's. I also have an inReach for Smartphone (which itself uses lithium AA's). But at some point I could see myself taking an inReach SE, a Steripen Freedom, maybe a Kindle, or some other sort of USB-charging device. And when I travel other than backpacking I take an iPad. Haven't tried the Energizer charger with the iPad.

At home I use one of these during power outages:

Chris .
(cwb) - F

Locale: Los Angeles
Chargers on 03/27/2014 13:29:42 MDT Print View

That Energizer one will charge your average smart phone in about 6-8 hours, one time. I have a 4000MaH thin charger from Verizon that is the same size and weight as my phone that will charge it from full dead in about 45 minutes, but again only once. I don't think the battery powered ones are worth the time in my opinion, but again, it depends on how long and how far you are from power.

Mike W
(skopeo) - F

Locale: British Columbia
device chargers that use lithium AA's on 03/27/2014 14:03:16 MDT Print View

You have misinterpretted what has been said on the other threads regarding the Miller charger/power supply (mentioned in the inReach thread). It is DEFINITELY NOT an AA battery charger like the Energizer.

The Miller Charger is made to use a single Lithium rechargeable 18650 battery. This is a 3.7 V 3400 mAh battery that is quite large compared to an AA battery. You can't buy a disposable version of this battery (at least I'm not aware of one).

The Miller charger with the single 18650 can charge my iPhone twice or my inReach once.

Edited by skopeo on 03/27/2014 18:14:44 MDT.

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

Locale: Silicon Valley
Re: device chargers that use lithium AA's on 03/27/2014 14:13:43 MDT Print View

I wonder if there is another device charger that uses _four_ lithium primary batteries instead of three. If so, I wonder if the higher voltage would do anything disruptive in the device battery.


Adam Berg
(AdamMBerg) - F - M
Re: device chargers that use lithium AA's on 03/27/2014 15:15:03 MDT Print View

Thanks, Mike. That's exactly the kind of info I was looking for. In the picture it looked like a AA, so I thought they were the same size.

Troy Childs
(tchilds) - F
charging on 03/27/2014 18:17:59 MDT Print View

Have you looked into the various lithium ion chemistries?

The 18650 3400mah battery mentioned is a good one. However there are various sizes of batteries available for charging USB devices. As big as you need there's no limit and they're all very efficient for the weight.

Furthermore there are other devices for charging including the 2 ounce Brunton hydrogen reactor which puts a 10,000mah li ion to shame in terms of efficiency per pound.

There are also solar chargers and Peltier chargers available in the 10,000mah Li ion weight range. Examples of these are the flamestower
or a hand generator.

The cobalt chemistry (ICR) Li ion batteries are the most efficient option per pound until you get into hydrogen reactors or over 10,000mah of power demand.

It is very easy to build your own 5v micro USB regulator as well and use any 3.7v Li ion cell you wish on the diy route.

Edited by tchilds on 03/27/2014 18:21:27 MDT.

Ryan Smith
(ViolentGreen) - F

Locale: Southeast
Re: device chargers that use lithium AA's on 03/27/2014 20:20:15 MDT Print View


I use a similar setup to the below and it comes in at ~7oz. If you don't need that much capacity, you can take only 1-2 18650's or get a battery bank that only fits 1 or 2.

Rex Sanders
(Rex) - M

Locale: Central California Coast
Re: charging on 03/27/2014 23:23:51 MDT Print View

Furthermore there are other devices for charging including the 2 ounce Brunton hydrogen reactor which puts a 10,000mah li ion to shame in terms of efficiency per pound.

According to Brunton:
  146g Reactor, 242g with Hydrogen Core

242 grams is 8.5 ounces. That's what you have to carry to recharge anything.

Each Brunton hydrogen core delivers 4500 mAh at 5 volts, or 22,500 mWh, or ~93 mWh per gram of carried weight.

The combination of Miller charger and Panasonic 18650 battery delivers about 3400 mAh at 3.6 volts (slightly less due to conversion loss), or 12,240 mWh, or ~156 mWh per gram of carried weight.

There are also solar chargers and Peltier chargers available in the 10,000mah Li ion weight range. Examples of these are the flamestower or a hand generator.

The Flamestower is really impractical:
  ... it will take three hours to completely charge your phone with FlameStower.

So you get to carry a 10 ounce charger that needs three hours of sitting in a hot fire (plus adding cooling water), to charge a phone, once?

Am I missing something?

-- Rex

Edited by Rex on 03/27/2014 23:25:35 MDT.

John H
(pastyj) - F

Locale: SE US
Re: Re: charging on 03/28/2014 07:37:04 MDT Print View

I have yet to find anything simpler, more reliable, better performing or cheaper than Jackery external batteries.

The Bar is 5400 mAh, 5.4 oz, $29 and will charge an iPhone 5 ~2.5 times.
The Giant+ is 12,000 mAh, 10.4 oz $49 and will charge an iPhone 5 just over 6 times.

I use the Bar for backpacking and the Giant+ for kayaking. Combined with keeping the phone in Airplane mode when not needed, the Bar will keep me charged for over 12 days.

I am not affiliated with Jackery...I just like an use their products.

Troy Childs
(tchilds) - F
18650 for the win on 03/28/2014 10:06:08 MDT Print View

Sorry my numbers were off. It looks like you're best off carrying up to 10,000 mah USB external batteries period.

Darn interwebs misinformed me on reactor weight.

The 18650 is what a lot of ecigarette users are carrying around. It is hard to beat unless you need more than 10,000 mah.

There are lighter more efficient lithium polymer cells that can hold more amp hours but they run in a series circuit to lower the drain across that type of very low draw chemistry. This is where you'd have to DIY a charger to get ahead of the 18650 cobalt chemistry cell at 3.7v.

I don't know of a commercially available option that uses higher capacity lower draw cells in series to accomplish this feat. By the time you regulate the voltage down that far at a full charge it would end up pretty close. You'd certainly have to run at least two 2600mah lipoly cells to get ahead of two 3400mah ICR Li ion 18650s. Even then I don't know if you'd even benefit.

I run higher voltage charger that I built but it uses much larger cells than were talking here to benefit me over 3.7v cells.

In short run 3.7v up to 5000mah and carry up to 10,000mah before looking into more complex alternative.

I still like the flamestower at 10 ounces for reading on a Kindle by the fire... If it works lol isn't out yet. It has merit over carrying light for a book versus a reader plugged into your fire though potentially.

Edited by tchilds on 03/28/2014 10:34:11 MDT.

Troy Childs
(tchilds) - F
cells/cells on 03/28/2014 15:04:38 MDT Print View

Charging a cell off of a cell really cuts your cycles in half. Not very green of us to do so.

That's the part I forgot to mention trying to weigh all your options.