Update 7/25:
I’ve tested it this weekend. I have done 3 full charging tests on my iphone 4. I had my iphone die out completely where it had to shut down. The external battery charged up my phone to about 75-80%. Although not a full charge, for the price, it’s a very good deal. If your phone was down to about 20%, the external battery should be able to fully charge it. I also tried it on my old ipod photo 20GB and it fully charged it with room to spare.
Overall, for the price, its more than worth it, it’ll be good on long trips, plane rides, camping etc. Shipping took about 2 weeks because it came from a slave shop in China. I think you can probably pull off a 3-5 day safari deep in the Amazon rain forest with this thing combined with your iphone’s internal battery on light usage.
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I ordered this rechargeable battery yesterday, I think its a good idea for long trips or out camping. It can fully recharge any ipod or iphone and it's also rechargeable, 1900 is the biggest size I can find.
They are selling them for 7.19 shipped on ebay, that's a fantastic deal for a battery like this.
http://cgi.ebay.com/ws/eBayISAPI.dll...fvi%3D1&_rdc=1