high on solder

After my previous experiments measuring power usage I decided to test how much of a difference the LCD backlight made in the power usage of my laptop and my HDTV. My laptop has a 13.3" screen with an LED backlight which is supposed to use less power than the typical fluorescent backlight.

• Backlight 100% - 26W
• Backlight 50% - 20W
• Backlight 0% - 19W

These readings show why reducing your backlight while running on battery can significantly improve your battery life. It also demonstrated to me that it's not really worth turning down the backlight below 50% since it only saves you 1W. While these results are interesting I wish I could compare them to the normal version of this laptop with the fluorescent backlight.

My HDTV is rated for 145W on the back of the unit, however, as part of my calibration of the display I turned down the backlight to improve the black level for better viewing in a dark room. The backlight control has settings from 0-16, I set mine to 5. At this reduced backlight level, my HDTV only draws 80W. For all the talk of flatscreen TVs drawing tons of power, if you adjust its backlight to a reasonable level, you can significantly reduce its power usage and improve its picture quality at the same time.

Update on Saturday, November 22, 2008 at 3:31PM by Joe

I recently purchased a new Samsung 37" 1080p LCD HDTV and took the following power usage measurements with my Kill-a-Watt while I adjusted the backlight control.

• Backlight Setting 10 = 199W
• Backlight Setting 9 = 166W
• Backlight Setting 8 = 161W
• Backlight Setting 7 = 154W
• Backlight Setting 6 = 145W
• Backlight Setting 5 = 136W
• Backlight Setting 4 = 127W
• Backlight Setting 3 = 119W
• Backlight Setting 2 = 111W
• Backlight Setting 1 = 104W
• Backlight Setting 0 = 96W

In the course of setting up my TV I found that setting the backlight to 3 made for the best overall viewing experience. As you can see it also saves me 80W of power over the highest backlight setting and 17W over the default setting of 5.