Macbook Battery

I have a macbook that is 33 months old according to the coconutBattery utility I downloaded yesterday. I also used the onyX utility to clean things up a little thinking that may be part of the problem. I bought a new battery because the old would not hold a charge any longer. The new battery had a 38% charge when I installed it so I ran it down to nothing and recharged it to full. I turned it on and like a gas guzzling sports car, in the span of about 3 hours I drained it. I charged it to full last night and over 30 minutes today have lost 20%. That seems too fast. Do any of you have suggestions of where I went wrong and what I might do to remedy the situation?

My apologies for starting a thread on a topic that has been done to death, but I haven't found an older post that answered my question. Thanks to you all!

Batteries are not an exact science. There is no "float in the tank" as you would have in a car to tell you the fuel level.

Instead, the estimates you see are educated guesses based on usage trends and the way the battery responds to those trends. When you replaced the battery, you essentially reset everything the SMC knows about your battery. So, it will take a little while to learn about your new battery.

First thing you should do is charge the battery FULLY. Then, run it down on battery until it is fully depleted and goes to sleep. Close the lid. Attach the power adapter and leave it alone until the MagSafe indicator turns green.

After that, your estimates should be a little more accurate. But remember, they're just estimates, so take them for a grain of salt and just use your machine and don't sweat what the gauge says.

Thanks CWA

I really appreciate your help CWA. I remember purchasing the macbook and seemingly going for 4-5 hours on a single charge and this falls way short. I really should have charged it out fully before using it, but I needed to finish some work and forgot to follow the rules. Have a good one!

Apple has a great site for how to maintain and use your batteries properly for all of their devices:

Apple - Batteries

In addition, you'll find a lot of great information by searching here at Mac-Forums. There are many threads out there that you'll find useful on this subject:

Mac-Forums.com - Search Forums