Backup USB battery

I use a Duracell PPS2. It's simple to use and gets the job done without any drama at all. It's very slim and light. When my phone needs a charge, I use it with a very short cable, but when my headset needs a charge I use a longer one. The battery's cake, cables are the hassle point.

I keep it in a little kit bag with AC & DC chargers, and all the various cables needed to charge all my gizmos.

If you're hoping to charge an iPhone this is a good read - iPhones are notoriously finicky chargers because different models require different voltages / ground on the USB data pins - some chargers ignore those data pins and it can cause problems charging.

http://www.ladyada.net/make/mintyboost/icharge.html

I find the most reliable way to charge is to get something that has a 12v car socket, then use an iPhone specific car charger. I've had mixed luck with USB chargers.

@Wayne R: Have you used it with an iPhone? If yes, which model? @itsrob: regarding your "mixed luck"... which one worked? or worked best?

Thanks!

The one I'm currently using successfully came as part of a more expensive solar kit. The battery is a 5400mAh lithium-polymer battery. It is remarkably lightweight but is bigger than my phone. I use it to top off my phone at night during campouts which it can do 2-3 times before dying. The solar panel is slow to charge but I usually just charge the battery via USB before leaving town. http://www.amazon.com/StrongVolt-Charger--18Watt-Portable-Folding/dp/B005N1P7HM/

This solar panel / charger doesn't charge an iPhone (but I did have luck with other phones). http://www.amazon.com/PowerFilm-USB-AA-Solar-Charger/dp/B001RMBHMK/

I think if it specifically lists the iPhone (like in your original link) you are probably going to be ok.

I use the Just Mobile Gum Pro. It's powerful enough to completely recharge my iPhone in a bit over an hour, while still being small and light enough to be pocketable. iLounge gave it their "Highly Recommended" rating, and it gets 4.5 stars from users on Amazon.

Just Mobile has a couple of newer models with slicker packaging, but the Gum Pro has a more rugged case and the best size+weight to power ratio of the bunch. If you're looking for something with more oomph, there's the iSound Portable Power Max, which has more than triple the capacity of the Gum Pro (with correspondingly greater size and weight), but the reviews seem to be much more mixed on all of the larger battery packs.

I've used this rechargeable battery for about a year, and it's fine. (I use it with various Android devices, not an iPhone).

In case you cannot follow the link: it's described as "New Trent iCarrier 12,000mAh Heavy Duty 2A/1A Dual USB Ports External Battery Pack".

pamar @ Did you bought New Trent external battery? Would you like to give feedback please. I am thinking to buy that External Battery. I am personally using usb battery http://theeffectiveguide.com Streamlight Protac Hl USB flashlight is the perfect for this type work.