• The battery is bigger than needed.
• The system is running at 5 volts.

..this means i can use the USB port i took off the power adapter, mount it on the side, and charge my phone while i am sat by the river!

This could also be put to other uses, eg. when mounting a GoPro camera on the board it could be powered by USB, making sure it keeps on filming.

Edit: Mounting GoPro's on a longboard doesn't work very well, far too much vibration.