the ipad has 2 batteries, and each 1 is the same size as the iphone. The power coming from the batteries though is MUCH higher than the previous model.

This will probably mean that the next iphone will have more juice, but given the OS 4.0 speculation and its rumored inclusion of 'expose type multitasking' it would mean it needs the extra juice.

Perhaps after the OS 4.0 is updated on the IPAD, it will JUST manage to reach the 10 hours.