how many watts does it take to run a 15" macbook pro?

85w i think, but not 100% sure.

Yes it is 85 watts but I have read that it can run on 65 watts.

The MacBook Pro operates on an 85-watt power adapter although the nominal value may be less depending on usage. (see technical specifications)
Re: http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/wo/0.RSLID?mco=9 25997E8&nclm=MacBookPro
Regards,

I have a Macbook Pro and a Macbook.

The Macbook has a 65 watt adaptor and the Macbook a 85 watt. I can use both off the adaptor on both macbooks without any problem. Short, i can use perfectly a 65 watt adaptor a my Macbook Pro.
Anyway, Apple does not give a 85 watt adaptor for fun, so i quess it is better to use 85 watt instead off 65 watt. But iff you dont want too use to much power, 65 watt will be enough. But i think you have to buy a macbook adaptor for your Macbook pro!

that's interesting. I also have both a MB and MBP but have always been very careful not to mix up the adapters.
How long have you been doing this? Do you find that the 65W adapter on the MBP tends to run hotter becuase of the increased demand for power?

d

If i do use the Macbook adaptor on the Macbook pro, then the adaptor is not hotter then the Macbook Rro adaptor on the Macbook. I have to temperatured it exact, but it feel the same.

Als the charging time is exact the some, so i do not see much different whil using them.

But again, i prefer using the 85 watt adaptor, apple does not for nothing give a bigger-watt adaptor with the Macbook Pro. Anyway, i have uses the Macbook adaptor on my Macbook Pro for some days, and there were no problems or different with the Macbook Pro adaptor.

So just use the Macbook Pro adaptor always on you Macbook Pro. But in a car or ship, where is less power, there you can use the Macbook 65 watt adaptor without a poroblem!