What can explain why the brand new battery for my Macbook Pro drains so fast?

Try reading this article to see if it helps.

http://www.articlesbase.com/hardware-articles/maximize-the-battery-life-of-your-macbook-pro-1058066.html

@MrGeneVan Thanks, but this battery is brand new and has this issue. I will keep those tips in mind for this one (in fact, I was doing all those things except turning down the backlighting.)

One of your tags is overheating. Is the fan always running? That will kill your battery pretty fast. If you are just browsing and using word your fan shouldn’t really be running. (unless you visiting a page that uses Flash)

@johnpowell The MBP does seem to be hot, a lot, especially in the back left where the power adaptor connects. The fan runs frequently, but I’m not sure if it is running too frequently, not enough, or just right.

Try calibrating your new battery. It is possible that your battery has enough capacity but your computer doesn’t think it does and reports the wrong percentage remaining.

Also I feel like resetting the PRAM (and perhaps the PMU) might help although I can’t find anything concrete that says that might fix any battery issues.

did you season it correctly?

@shilolo your battery shouldnt run out so soon, my macbook pro battery lasts like 7 hrs!!!! i think something is wrong with the computer perhaps?
hope this helps

You know this happened to me and i saw a apple genius. They stated that a process was sucking up CPU cycles and therefore draining battery. Go to your activity screen and watch the processes.. if your machine is constantly running over 10% of total CPU power then something is running that you need to manually shut down.

Install iStat menus. You can easily monitor temperature, fan usage, and CPU activity. If any of these seem excessive, you might be able to pinpoint a hardware or software issue.