T61 Question, built in Light in the LCD

I have a thinkpad X30 which I love to death, but its getting on the slow side even for just basic tasks. One thing that I really like is the built in light in LCD lid so I can use my notebook in my bed in complete darkness. Can anyone confirm they do in-deed has this feature still?

 

My R60 has one.

 

Yes it does.

This PDF gives alot of info:
http://www.notebookreview.com/assets/22089.pdf

The Light is called Thinklight

 

is the thinklight on models with the camera?

 

Thinklight is a standard with ALL thinkpads except X series.

 

Thanks for confirming this. I was unaware that this was a standard feature and completely ignored this little helper.

How is the battery life when using this? Significant difference or barely noticeable?

 

id guess its an LED which is hardly any power draw.

 

Flipping back and forth between light on and light off, it doesnt change the watt meter any bit, which goes out to the hundredth of a watt.

 

A small LED like that will likely have a maximum current of 20mA at a maximum forward voltage of maybe 3.2 V. So P = VI, P = 20e-3 * 3.2 = .064 W MAXIMUM. My laptop has a typical 6-cell, 65 Watt-Hour battery. If that battery lasts me 2 hours, that means I'm drawing 32.5 Watts over an hour. If I also use the light constantly over that hour I'm drawing 32.5 + .064 = 32.564 watts over an hour instead of just 32.5. So in the end I end up using 32.564 * 2 = 65.128 watt-hours instead of 65. Creating a ratio I see that:

120 - (65/65.128 * (120 minutes)) = .23584 minutes

This means that if you keep your light on for the entire duration of the battery, you will lose 14.15 seconds from your battery life maximum.

So you can see in the worst case scenario, having your light on barely affects your battery life.

 

DAMN, can you provide some actual evidence to support your answer?

 

The math is there, I don't see any reason why real-life performance would deviate from the known and proven mathematical rules of electricity.

 

someone is/was an EE major

haha

 

Not in sarcasm, though.

 

my x60 has the light and i must say i love it. never knew such a little thing could be such a bonus until i got one.

 

Haha yup, IS.

 

Maybe you could make yourself a little more clear.:twitcy:

 

That pretty much summarizes it.
U'll lose 14.15 seconds max in a worst case scenario.

It's negligible battery life loss.

 

I was being sarcastic. I think xnviews was crystal clear.