I recently came across a few different external power packs for iPhone, including a Kensington Powersled and a iPower2 (not sure which brand). Apparently, these things will double your battery capacity.

Have you tried one of these, or a similar device? Thoughts? Thanks!

Jarle, I've used the Mophie Juice Pack Air with my old 3GS and it was very good. The juice pack attaches to the back of the iphone like a thicker case (so it doubles as a case protector -- but without front cover). It has a charging connector and as you charge the iPhone it also charges the juice pack. You can opt to keep the Juice pack Air in standby mode until you absolutely need it. It does not block the camera, buttons, etc.

It worked like a charm -- I took it on a longish flight and it kept my 3GS totally charged through the flight and then some. Unfortunately, I had to return it to the friend who had lent it to me!

The only dislikes I had: the extra bulkyness. I carry my iPhones in my pants pocket and I like its unobstrusiveness. The Juice Pack definitely increases its size. It is not horrible =, and they took great care in designing it smoothly, with nice lines, but it does add size and weight. Another thing: in my case the Juice Pack had a smooth back, which made it easier to take out of my pocket (or put it in), but it also provided little "grip" help.

If I still had it I'm not sure I would use it everyday (I seem to have chargers everywhere I go),, but I would definitely use it while traveling.

N

Thanks. Will be going on a long distance flight soon. May have to get one of these.

Monoprice.com has several, and great prices. I purchased one before my last vacation since I was relying on my 3gs to be the sole camera/cam-corder/gps/ereader/ipod/videogame/laptop/portable dvd player replacement system and was worried about battery life. I got 3 charges from the one I got and never had a problem.

I've been using an emergency charger from dealextreme that runs on 2 AA batteries, along with a super-short cable (also available at DX). It's obviously nothing like a charger case in terms of pocketability, but it's cheap and it works.

Monoprice, sadly, has yanked everything that has an iPod connector on it. I'm guessing they were not paying the iPd tax and they've been under pressure from Apple.