The Dock-Square includes iPhone/iPod dock connector, PC USB connector, and stereo outputs.
One difference in the Battery-Square circuitry is that we've included a resettable fuse to protect the circuit and batteries from high currents in the event that the magnetic toes are shorted. From the Kickstarter feedback we received earlier in the project this fuse is a very necessary feature. However, as a result some devices that require high spikes in current may not operate in the same way with the Battery-Square as other chargers.
For best results you should make sure to fully charge the 3 AAA rechargeable batteries that come with the Battery-Square. Also, when using a single Battery-Square the best performance is achieved when the device being charged has a charge level of lower than 50%. Finally, charging the device with the device powered down improves the efficiency of the charging process.
Using two Battery-Squares in parallel (with both '+' connected) provides the best performance for high current devices, such as iPhones and Android smartphones.
Device not supported!
The Dock-Square circuitry is very similar to the open-source circuit design used in the Minty-Boost; a standard 5V DC voltage booster with specific resistors on the iPod/iPhone data lines. Particularly with the iPhone 3GS it's not uncommon to get "Device not supported" message, which usually goes away after removing the iPhone from the dock and reconnecting it.