iPhone external battery options

[trousers]

I'm looking for a portable battery booster for my iPhone and can see several options on the market.

 

There seems to be two main types though:

 

a) ones that come in an external case form that you slot one's iPhone into (e.g. http://www.powerskin.co.uk/ or http://www.juicepack.co.uk/batteries/juice-pack-airtm-iphone-3g-and-3g-s.html )

 

or

 

b) one's that come as a block that one simply plugs into one's iPhone via a connection lead

 

The main consideration for me is the solution that gives me the most additional charge time. The skin solutions seem to offer about 1 full re-charge whereas (I believe) the external block variety may offer more. That said, I like the concept of the skin ones.

 

Any recommendations?

 

cheers

[saint_stevo]

Are powermats out yet?

[saint_stevo]

edit- useless for what you want it for anyway!

[saint_stevo]

http://www.gadgetsnews.co.uk/post/2009/07/29/iPhone-to-go-green-with-the-latest-solar-charger.aspx

[mdearlove]

http://www.amazon.co.uk/Duracell-Instant-Power-Charger-PPS2/dp/B001GXNJLC/ref=pd_sim_sbs_office_1 works as long as you have the sync cable. It will charge any USB device