why only 2 prong and not 3 prong? kind of useless, can't even plug in my laptop directly

where can a person buy a 3 prong to 2 prong adaptor?

 

homedepot? chances are there wont be enough power to charge your comp. unless mines just a piece of junk...

 

Works fine for my laptop. Any hardware store will have an adapter. Do not forget to push the button to turn it on....

 

mine cuts on and off like every 10 seconds... mac book, cell phone, everything...i gave up on it

 

Mine charged my lap top, and my power tool batteries fine. Maybe your inverter is defective.

 

isnt that third prong just a ground?

sould be no different than a standard outlet for power

 

Depends on the technology of your charger. Problem is that you are going from 12VDC to 120VAC back to ?? DC. Some power supplies don't like running off the square wave (Chopped) 120VAC.

 

I have not had any issues charging laptop and cell phones/ipods.

 

You cannot get AC from a square wave. You can get AC from a simulated sign wave and that is what the inverter does. But you are correct that it is a chopped up simulated voltage pattern. Dirty as it gets unless the truck has a rotary converter which I doubt it does.
The reason there is no third ground terminal on the 120 volt receptacle is because you have no earth ground like you do in your house.

 

Square wave is what you get from cheap invertors (as opposed to a sine wave)

http://blog.rv.net/2008/06/choosing-an-invertercharger/