How to power a laptop from a cigarette-lighter outlet
Although manufacturers sell 200-watt inverters, most cigarette lighter sockets only crank out 96 to 120 watts. Check the
wattage shown on the laptop power supply (or whatever other device you want
to power) to find its wattage. If yours is 90 watts (typical for a full-size laptop),
you've already maxed out the typical car's lighter socket. If you need to power two laptops, don't add a power strip or octopus adapter. Adding a second power supply
would overheat the inverter and most likely blow the cigarette lighter fuse.
Instead, buy a second inverter and
plug it into a different socket if you
have one. The bottom line is
that you can power up as
many devices as you want
as long as the total doesn't
exceed 100 watts.