Prof John L said:Dusty,
Basic electrical formulas suggest that to produce 2000W from a 12V source would need 2000W/12V = 166A.
That suggests that a 110Ah battery would be fully depleated in about 35 to 40 Minutes.
To run the hair dry you would of course need a 2000W 12Vdc to 230Vac inverter, which will also use a little power of its own.
BUT, There are a number limiting factors that might reduce that time further.
Caravan battery chargers will only charge a battery to between 85 to 90% of its full capacity. So at best your 110Ah battery will only have about 95 to 100Ah.
As batteries age, their capacity is also reduced.
Also leisure batteries do have a limited maximum current draw so you would need to check the batteries specification to see if its is capable of supplying 166A.
Further, Most inverters have a battery protection system so if the batteries terminal voltage fall below a threshold it turns off. Its quite possible the battery may still have 20 to 30Ah charge remaining, but is unavailable to the inverter.
So all in all you may get 20 Minutes from a caravan charged battery.
Alternatives:-
Only use sites with EHU, Get a 2kW generator,
Send the OH to the toilet block where a 13A 230V supply is available,
Tell her you love the bad hair day wild look!
Thanks John
I'll stick to EHUs and gas.
Better still SWMBO can have the bad hair day!