[Ti] PowerBook energy usage

[Arjan Bos]

On 16 mei 2004, at 10:43, Kynan Shook wrote:

> Well, I just thought some people on this list might be interested in 
> how much power they're using by doing certain things, especially for 
> those extremely concerned about making their battery last as long as 
> possible before they need to recharge;
  Well, from your figures one can easiliy calculate how long a fully 
charged top condition battery is going to last.



> 12"/1 GHz/80 GB/768 MB/SuperDrive (47 Watt-hour battery)
>
> Approximate power use for various things, and which of the computers 
> the measurements apply to:
<snip/>
> Minimum power consumption: HD spinning but idle, backlight at minimum, 
> Airport and Bluetooth off, minimal CPU and GPU usage: 12 W total for 
> the whole computer.
47 Watt-hour battery / 12 Watt minimum consumption = 3.9 hours, or 3 
hours and 55 minutes.

>
> 17"/1 GHz/60 GB/1 GB (55 Watt-hour battery)
<snip/>
> Minimum power consumption: HD spinning but idle, Airport and Bluetooth 
> off, backlight on at lowest brightness, minimal CPU and GPU usage: 16 
> W for the whole computer.
55 / 16 = 3.4 hours, or 3 hours and 26 minutes.

> Typical power consumption: HD reading and writing occasionally, 
> Airport on, backlight at about half, moderate CPU usage, etc: 20-35 W.
roughly two hours on battery


> Maximum power consumption: battery at fast charge (other sources of 
> power drain, eg display brightness, just take power that would 
> otherwise go to the battery, the total power usage doesn't change at 
> all): 60 W
>
slighly less then an hour on battery.


> It should be noted that these measurements (especially the ones for 
> the whole computer) are NOT the same as what they'd be while on 
> battery power: the power adapter takes some power, and some things are 
> affected by a power change that can't be simulated on AC (some 
> circuitry isn't used on battery, the speakers and sound circuitry 
> won't turn off while on AC, etc.).

>  The 16 W minimal usable power drain would likely be several Watts 
> less while on battery power, but I don't have an easy way of testing 
> that.
>
So here you might gain a few minutes.

---
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