[Mobile-Portable] Computers

[N1KHB at aol.com]

Hi All,
   In consideration of a suitable external power  source for a laptop while 
on portable ops such as portable ham radio, I'm  wondering how accurate the 
common 19 volts needs to be for proper operation.  I've already thought 
about running the normal power supply from an inverter, but  I'm looking for 
alternatives nonetheless and in any case I remain curious about  the voltage 
spec. Thanks!
 
Sonny N1KHB