Eton Corporation has just announced the new Eton Mobius iPhone 4 battery pack, which will give you extra juice while you are out and about. The Eton Mobius can be charged via a USB port, but it is also equipped with a large enhanced Monocrystal solar panel on the back which is almost as big as the iPhone itself. Solar powered charging usually doesn’t look this good.

The Eton Mobius has a 1800mAh battery and will add about 20mm to your iPhone’s thickness, while doubling your iPhone’s battery life. It will charge your iPhone directly from the sun at a rate of 20minutes of talk time for every hour in the sun.

Mophie’s juice pack air external case added some battery life to the iPhone, but it also makes your iPhone chubby. Now Mophie is introducing a line of external juice packs that pop into your device using a retractable dock connector.

The smallest will be the $40 1,000mAh juice pack reserve, then the $60 1,500mAh boost. Both are compatible with the iPod and iPhone and also offer “super-bright” LED flashlights. Lastly there’s the juice pack power station, which hasn’t been given a price or mAh rating, but will be compatible with the iPad.

I have been using a Mophie Juice Pack for my original iPhone for a long time now. The device gives me much more call time and lets me play games and music longer before the phone is dead. Using the Juice Pack I get roughly twice the run time on my iPhone.

Mophie has announced a new version of the Juice Pack for the iPod touch 2G that promises significantly more run time when used. The touch 2G Juice Pack fits onto the iPod like a case and provides up to 72 more hours of playback for audio and up to 7 hours more for video.