Q. What uses the most battery power on my laptop?

We had a reader ask about this article:

The question posed in the subject line was addressed in the Windows Tips & Tricks eLetter for April 6, 2009. This is great information but I have a question. I've heard that wireless networking "eats" battery life like crazy. That is why most current laptops have a way of shutting down the radio when not in use. Is this true? Is that factored into the "network" result of 4%? I would expect this result to be much higher if wireless networking is truly an issue.


Here's John's response:
Interesting question. After some additional research it seems that most modern wireless networks/bluetooth are not the huge battery killers we typically think they are compared to something like a large laptop screen. The 4% includes wireless/bluetooth. Yes, its great to turn them off if you are not using them but consider the average mobile phone and its tiny battery. Those devices have wlan/Bluetooth and can run for a day. Now consider the battery we have in a laptop and the proportion of battery used by the wlan/bluetooth is pretty small compared to everything else. Turning off is also good from a security perspective to not have networks available that you are not using.