I've got a 2012 Honda Odyssey. I'm wondering if I can plug in my hair dryer or if it will overload the car. It uses 1500 watts I think...not sure what wattage a car can handle.
Your owner's manual will explain what the inverter plug is rated for in watts. The hair dryer will also have a label explaining the maximum watts.
I'm pretty sure the answer is "no". That plug is for laptop chargers and very small electronics that do not draw much current. A hair dryer (with the heater) is a huge electrical load - even if it is the 1500 watts you think, that represents almost a 13 ampere load @ 120 volts AC.
I doubt the inverter system in your Odyssey is rated for that.
I could be wrong - I suggest checking the owner's manual to be sure.
A quick internet search seems to suggest that each outlet is only rated for a maximum of 120 watts. Far below what you would need. The fuses seem to be 10 amps, so at roughly 12V DC that means a maximum of 120 watts before inverting to AC.