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Laptop batteries are a fascinating work of engineering. They live, they die, and then they are resurrected. I have always struggled with prolonging each brief recharged life in my laptop batteries ever since my first Powerbook 145B back in 1993.

Now I have a late 2008 aluminum unibody MacBook (MacBook5,1). I am a little displeased with my battery life, which usually tops out between 4-5 hours (I believe I was promised at least 6 hours when I purchased it). However, I have figured out a few things on my own and read others on the net that may lead to longer battery life for your MacBook or MacBook Pro.

• Power cycle your battery. I do this each time that I use my Macbook. What this means is to run your MacBook off its battery until it goes into deep sleep. Then, plug your power cord in and let it recharge completely. This keeps the battery properly calibrated.
• Turn off your radios. When I’m on the go, I always turn off Bluetooth, because I don’t carry my wireless Mighty Mouse with me. Also, I only turn on Airport when I plan on surfing the web.
• Reduce your screen brightness. I lower my screen brightness to the lowest level, which works fine in good indoor lighting.
• Run fewer concurrent apps. This means not only running fewer apps that you directly interact with, but also keep background running apps to a minimum. If something is eating up processor cycles, then it is eating power from your battery.
• Streamline your browser. During the school day, I usually only leave Safari open as I go from class to class teaching. Flash is terribly inefficient on MacOS X (I say this, because it is hard to imagine how Flash ads can cause Flash to take upwards of 100% processor use, leading to more heat expenditure, and increased fan use). Make sure Flash is up to date, and install Safari AdBlocker (64-bit) and ClickToFlash to reduce ad trash and invoke Flash when you want it. Also, I only use one tab/window with Safari 4 to reduce its memory footprint and hopefully processor time.
• Try other browsers. In this article, AnandTech demonstrated that your choice of browser and the things that you browsing will affect your battery life. However, they tested a number of browsers on PCs, and not Macs. Obviously, the underlying hardware on the newer Macs and PCs are similar, but the applications themselves on the two platforms will be affected by the OS, APIs, different library builds, etc. So, I don’t know which browser works best on Macs to increase battery life, but I do hope that someone out there will run a methodical test to determine which browser at the moment saves the most juice. If you do this, please post a comment with a link to your results.
• Leopard vs. Snow Leopard. I am currently running Snow Leopard, and I do not find an appreciable difference in run time between the two OSs. However, there is a tremendous amount of debate over this issue online. This is something else that requires methodical testing to determine, and I have not found anyone to have done so on a baseline piece of hardware.
• Be radical. Some folks online have removed their optical drives in order to save a little power, and others swear by SSDs at saving more power than traditional HDDs. My MacBook has an Apple supplied SSD, but I do not have another MacBook identical to mine to compare run times.
• What did I miss? Leave a comment below.