"The Medway Handyman" wrote in message
...


My sat nav battery only lasts about half an hour unless plugged into the
fag lighter socket. I was told that the display screen is what consumes
the power.

The sat nav has a touch screen, but you can touch it with anything - the
end of a pencil for example.

The smart phone (Samsung Galaxy Ace) can be used as a sat nav for hours
without appreciably draining the battery and also has a touch screen, but
you have to use a finger or special stylus - the end of a pencil don't not
work.

Can someone explain the differences in technology?

In fairness, if you keep the smartphone screen on with real-time mapping and
GPS running constantly (as a dedicated satnav would) then your battery will
start draining fairly quickly.