Originally Posted by firewire
20 bucks for an 2,200 mAh battery? That is a great deal and the highest portable power I have seen yet. The site says that it's for both the 3g and 3gs, so like others said you probably have a contact problem. Nice find btw.
I found out that this error msg only pops up when the backup battery is empty.
So far I love this product: It provides one full charge for the iPhone, does not make the iPhone too bulky or heavy and it even has a cut out for the camera lens. And the price makes this a no brainer ...