Travel Technology - Power Saving/Security Advantage of Leaving Laptop Battery Home and Booting Off USB?

I just created a bootable Ubuntu USB stick. This means I can boot up my laptop without any hard drive whatsoever, and can store data on the USB stick.

If I took out my laptop hard drive before a trip and just used the USB stick, there is the obvious advantage that prying customs officers can get nothing, except what is on the USB stick (assuming I don't just throw it in the garbage before landing.) I am aware of the hard drive encryption options, but if one encrypts and doesn't show what is on the drive they can hold the PC.

Here, however, is my question - anyone have any idea on the extent of what I assume would be the positive effect on laptop battery life by using the laptop it without a hard drive?

The CPU and screen use most of the power. Removing a hard drive adds maybe 15 minutes to the battery life.

Title of thread should have been laptop HARD DRIVE not Battery.

Here's (http://www.codinghorror.com/blog/archives/001099.html) a kinda easy to understand analysis of how much power a laptop uses. Note that the baseline for an idle laptop is around 20 watts. According to this page from Toshiba (http://sdd.toshiba.com/main.aspx?Path=StorageSolutions/2.5-inchHardDiskDrives/MKxx54GSYSeries/MKxx54GSYspecs), their laptop drives use between 0.9 watts and 1.2 watts at idle. Note that it also uses 0.18 watts in standby, which means that with proper power management, your drive would use a negligible amount of power. I might even agree with Bobster and call the 5% of battery life that the idle hard drive uses negligible as well.

One thing I've been thinking about is how much extra battery life I could get by using only one SODIMM memory module. I've heard that DDR2 modules use around 4 watts so you could save 4 watts by only using one DIMM instead of two. Of course, this means your memory wouldn't be running in dual channel mode so it would be a little slower.

Anyway, good luck with your experiment. Let us know how it turns out.