Phone/USB charger using AAs or AAAs?

[dgjessee]

I'm experimenting with utilizing my smartphone as my only navigation unit (been using a Garmin Vista HCx and paper forever). For one particular trip I am pretty sure that this plan is perfect. The thing I am worried about is power. I don't want to have to rely on solar or walls to recharge my phone. I know there are some battery packs that would get me by for 1-2 extra days/charges. But what would be ideal is if there was a unit that could accept regular batteries and then charge a phone. I swear I've seen these before but I can't seem to use the right search terms anymore. Anyone have any suggestions? Used anything like this? Pros/cons?

[coldbike]

Goal zero makes them.  I have one to go withmy solar panels.  It is good for at least 2 iphonecharges.

[ImAFred]

If you go to Home Depot, in the battery section there is a very simple recharger(energizer brand) that with lithium(takes regular as well= one full charge and heavier than lithium) you can get two full iPhone charges out of a set(3). I have the 5 and I got the micro USB one then just bought a cheap micro to lightening connector and left it on there. Was considerably lighter than a goal zero set up even carrying another set of 3 lithiums(4 full charges) and you don't need sun to do it.... personally I'm disappointed with my goal zero set up.

[dgjessee]

Nice! And I even have a Home Depot gift card

[MartinFarrent]

I have an AA charger which takes four batteries. With lithium batteries, it's slightly lighter and much cheaper than a rechargeable battery pack. But you don't even get one whole refill on an iPhone 5. I'm back to battery packs.

Put it this way: About €12 for the AA charger. If you pack the lithium batteries from the outset, it's at least €6 per ride. If you buy batteries at a filling station en route, you probably won't get lithium - so expect a 45% (or so) refill. It doesn't take all that long to half-recharge an iPhone the normal way. Buy a coffee, and the guy at the filling station will probably let you use a plug.

Very few advantages to those AA chargers. Buy a battery pack, get two or three refills. For longer trips, get used to asking people whether you can use their electricity. Restaurants etc. always say yes.

[bumbler]

I built/use a Minty Boost [1]. Works fine; weighs 1.3 oz w/o batteries. Pack as many AA batteries as you'll need for a trip, or buy 'em along the way.

[1] http://learn.adafruit.com/minty-boost

[the tortoise]

Here is an option, and if you have a dynamo hub you could recharge the batteries on the go. http://www.amazon.com/Sanyo-eneloop-Pre-Charged-Rechargeable-Batteries/dp/B004UAG776/ref=cm_cr_pr_product_top

[DoctorRad]

In order to keep my old HTC Desire from discharging its battery when using its internal GPS receiver it needs a charge current of around 700mA. Many other mobile phones are similar. The Minty Boost and many similar battery powered USB chargers cannot supply this much current. If you connect them to your phone, if you're running the GPS, the battery will still discharge, albeit more slowly than if the charger was not connected.

Anyone wanting to go down the DIY electronics route may be interested in this regulator:

http://www.pololu.com/product/2119

Works with a very wide range of voltages, and can supply more current than the Minty Boost if it's stepping down. It's most efficient (i.e. will waste least energy and generate least heat) and can supply maximum current when operating from 6v, i.e. 4x Alkaline cells or 5x NiMH or (if you must) NiCd cells. It will, however, remain operating until these rechargable batteries are in an overdischarge situation, so you should use it with care.

It should also be possible to it from a dynamo if you rectify, smooth and voltage-limit its output before feeding it to the regulator.

[murf]

I'm not sure which phone you have, but if it's anything other than an Iphone you can buy spare batteries for dirt cheap. From ebay i bought 2 batteries and a charger , so i can charge them without having to be in the phone for $11 shipped

[Mike K.]

What phone and service are you using?  I ask because some work better for backcountry navigation than others.

iPhone 4 with AT&T service works great and I have lots of real world testing on this set up.

-- iPhone 5 with AT&T - no testing but I don't think it will work well for backcountry.
-- iPhone 5 with Verizon or Sprint - no testing but I do think it will work well for backcountry.
-- Other phones and service - no research or testing

This is how I use my iPhone 4 for backcountry multi day navigation.

1. Paper plan/map/narrative is primary and iPhone is for confirming turns or confirming I am where I think I am. Plus I would have the iPhone with me anyway so why not make do double duty. iPhones are rugged, especially inside a waterproof, schock resistance case (e.g. Lifeproof). I lash mine to the stem with closed cell foam cut to cradle it. The case keeps it warm enough without overheating.

2. Lock out the sim as Apple supports but do not turn on airplane mode.  This keeps satellite gps signal reception but stops the phone from wasting power searching for non existent cell service.  Unlock the sim only if you are in town and need to use cell. Lock out sim right after using cell service. Except for your GPS app (e.g. MotionX) manually turn off all applications from running in background. Power phone off completely overnight. While riding run the GPS app continually but turn off the screen except when you need it. I flip the screen on and off to confirm turns and run continually on fast descents if there are any turns coming up.  Set for appropriate background light. 

3. Before a backcountry trip, manually download to the phone's memory detailed terrain and road maps specifically for your route.  Balance map detail/file size vs. available memory and time to download.  Think GB's of data.  Works best overnight via wifi.

4. Recharge as needed from disposable AA lithium via cheap USB charger carried inside frame bag. It needs to be kept dry but also gets VERY hot while charging. Run the USB cable to the phone through the frame bag's water tube slit.

5. By miserly using power and really limiting GPS usage, I can go about 18 hours on just the phone's internal battery. The extra AA power is for backup or heavier than normal GPS usage. Two lithium AA easily charge the phone 4 battery from 20% to 80% in about one hour. There may be a little juice left in those two batteries, but not much. I ditch them and get a replacement set at the next opportunity and carry them in the turned off charger. You need to test that the charger you use outputs the correct power spec for your phone.

For me the main advantages of this set up are:

1. Since I'd be taking my phone anyway, no need to carry a separate, dedicated GPS device
2. iPhone is significantly more rugged and reliable compared to Garmin devices I've used.
3. The iPhone and the MotionX GPS app are easier to use compared to Garmin.
4. Option to turn on and use cell service.

The main disadvantage is power conservation necessitating not employing always-on, turn-by-turn navigation.

Hope this helps.



Hope this helps.

[dgjessee]

Thanks guys! I'm using an iPhone. I am starting to lean back towards battery packs. And also realizing that for endurance racing it's really not going to work for more than a day or so of racing (unless I'm planning to sleep indoors the whole time). I'm spoiled by my etrex Vista running for about 40-50 hours on lithiums and since it's only 3.5 oz, it's hard to justify the phone-only option. But as you guys said, the phone's coming we me anyway so I might as well try to use it. Anyway, you guys gave me lots to experiment with. If I come up with anything that's significantly awesome, I'll let you know. Thanks!

[Cortvald]

http://dx.com/p/portable-4-x-aa-charger-w-usb-cable-for-samsung-i9300-i9500-n7100-white-220486

works great for all USB powered items...
its gonna be my source of power on the 2014td

[dgjessee]

Nice, thanks! I found one at Home Depot made by Rayovac.