I am looking to purchase a power supply to take with me on trips. What product do you use to charge up your ipod/cell phone/gps while hiking?

Depends on conditions, how long the trip is, what options you might have along the way ...

In sunny and more southerly California I liked tying a Solio solar charger to the top of my pack, I thought it was worth carrying there. Not so much in Oregon and Washington, not just because of latitude but also more tree cover.

I recently did some tests with a lightweight unit by Energizer that takes two AA lithium batteries, but for my particular smartphone, at least, I wasn't satisfied with the results, nor were the results very consistent ... things just acted kind of wonky. I got some charge out of it, but it stopped charging at one point with the device far from completely charged and an independent battery tester saying that the batteries still had a lot of charge left. Go figure. Anyway, lithium batteries are expensive.

I've not seen any hand cranked units that are good for anything but getting a few emergency minutes of talk time, though it could be that something better is out there (?). There are wind power units, as well, and I've read that folks are working on something that uses biomechanics (your body motion while walking).

Bottom line is that it's still a PITA if you have any sort of power hungry device. The choice the typically works for me is to use a single device (my smartphone is cell phone, gps, journaling device, camera, etc), and carry extra batteries.

But again, the particular dynamics of the type of trips you have in mind, and how weight and price conscious you are, these can impact your selection a lot.

I do not take an Ipod or cell phone (no reception most places anyway) or GPS when I go hiking. The only items I take with batteries are my headlamp and camera. I put fresh batteries in the headlamp and camera before each trip and turn off the LCD screen of my camera to save power (it's useless in bright light anyway).

I go backpacking to get away from the electronic gadgetry of everyday life, and I don't miss it!

Your Mileage May Vary.... Just keep the volume really low when I'm around, please!

I do what OM does. Also, when I take scouts, I make it a rule that the only battery powered items they can take is a flashlight and camera. I do this so that they can experience nature and get away from all the gadgets. They use them enough at home.

But, if you want to, more power to you. I just can't answer your question other than bring extra batteries.

I've had good luck with products from Xpal They have small rechargeable battery packs that will charge your device. They even have one with a solar panel built in.

The thing that makes the xpal approach unappealing to me is that my device uses removeable batteries. I'd rather charge up and carry spare batteries that are made for my device than carry around what is in effect a spare battery in another form and then have to transfer (a subset of) the energy in the field.

But maybe this perfectly fits the bill for the original poster --- dunno!