Makers of smart phones have worked very hard to get longer battery life.
> For satnavs its nice, but less essential since they are most often used
> where there is power available. Older satnavs were often better due to
> being physically larger and allowing for larger batteries. However as
> the prices have fallen they have got smaller and cheaper in construction
> as well as price. My old tomtom go 700 can still do 4 to 5 hours on
> battery, and that has a (small) spinning hard drive in it. My phone
> could probably manage similar life - but 5 hours would take a sizeable
> chuck of its battery capacity (although its a physically very small
> phone and only has a 950mAh battery). The battery monitor on the phone
> is quite sophisticated and will tell you which activities are using the
> power. The display is the number one user. However enabling GPS uses a
> bit. Wifi uses quite a lot, bluetooth a little bit. Cellular data a fair
> bit (depending on signal levels).
and being in a steel framed building, where reception is almost impossible, eats up battery life.