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.
For "will a hair dryer overload my car?" yes, an inverter capable of powering this hairdryer is not going to be fitted as standard, but you could purchase one and fit it or have it fitted.