Who said "boost converter"?

Automobile electrical systems put out 12-15 volts DC. Most laptops
these days want 18-19 volts. Sounds like a boost converter to me.

5 - 8 amps? Why? Most laptops run around 30 - 50 W. So at 18V or so
that would be a measly ~3A output.

Actually, most current laptop ship with 60-90+ watt supplies, depending
on whether you want them to charge and operate at the same time.

If you're starting with 12V and require 18V output at 90W, it's pretty
easy to need 8A input.

I'd guess netbooks are a somewhat lighter load, though I haven't
looked it up.

De