it would harm the inverter and blow a number of the fuses on the circuit. Wattage measures the optimal potential a gadget might draw. It does not constantly choose that potential, yet, while it does, and the circuit can't furnish, fuses would be blown or, if incorrect fuses used, issues will catch on hearth. Now, many laptop adapters in recent times are rated for one hundred ten-240 Volts at 50-60-HZ. examine if yours is like that. if so, then the inverter isn't mandatory. EDIT: if your laptop's potential brick says "a hundred-240v 50-60Hz." then you definately might basically plug it into US circuits without concern. All you elect is a plug adapter, yet not an inverter. those plug adapters decide for some funds at return and forth shops. EDIT 2: Do you ought to run this off of a automobile inverter for 13h? it relatively is an entire new can of worms. those "wattages" are many times meant as "height" and not non-give up.