XO power management

Ismael Schinca ischinca at plan.ceibal.edu.uy
Thu Mar 24 10:41:24 EDT 2011


I'm planning to use different XO's, all of them 1.0 hardware. I definately
won't be able to finish today because they all have different OS images and
I think it would be best if I update them all (even for future tests). Maybe
tomorrow, maybe monday.

I think it will be very hard to perform the same test under the same
conditions as you suggest because:
- It will be very time consuming (though it doesn't need a lot of attention
during the test)
- The air conditioning in our building is quite frankly chaotic so
temperature is really variable (which is actually a lot worse for us humans
than batteries ;) )

The closer I might get, which I think could be pretty close is:
- Install the SAME fresh OS image and firmware version on all the test XOs
- Disable power management in every XO
- Keep the XOs close together
- The laptops batteries are mostly charged, so it will be a charge after
discharge, so I think temperature there is less of a concern
- Run the tests at the same time in every XO

Ismael

2011/3/24 Richard A. Smith <richard at laptop.org>

> On 03/24/2011 10:31 AM, Richard A. Smith wrote:
>
>  If you run _exactly_ the same test under the same conditions. Same
>> temperature, same test duration, same XO, then it might be possible to
>> compare the current voltage,
>>
>
> Battery temperature will also be a concern. If you test the discharge
> immediately after a charge when the battery is hot you are going to get a
> different result than if the battery was sitting on the table all night and
> is at room temperature when you start the discharge.
>
>
> --
> Richard A. Smith  <richard at laptop.org>
> One Laptop per Child
>



-- 
Ismael Schinca
Centro Ceibal - Depto. T├ęcnico - I+D
Avda. Italia 6201 - Edificio Los Ceibos
Montevideo - Uruguay.
Tel.: 2601 57 73 Int. 2232
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