If this is an external battery pack, don't forget to add its weight when comparing the iPad to his device. I think it's an amazing hobby project, but it's quite

If this is an external battery pack, don't forget to add its weight when comparing the iPad to his device. I think it's an amazing hobby project, but it's quite clear that getting ten hours of battery life out of a tablet is a tricky proposition involving tradeoffs from top to bottom of the hardware and software stack. e.g. Flash, pre-emptive multi-tasking :-)