[maemo-developers] [maemo-developers] Re: Measuring power consumption of 770

[From: Nils Faerber]

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david feldman schrieb:
> Will the 770 run with the recharger (or other external DC power source)
> attached, with the battery REMOVED? This could be same as the case of an
> expired battery that will no longer accept a charge. In this case, the
> only power consumed by the 770 would be by the machine itself, not by
> the battery recharge, nor assited by battery discharge.

Nope... look at the battery, it has three pins, not only two.
What you think is the third pin for? Hot air?
I guess not and if it is not connected the device will detect that there
is in fact *no* battery than an empty one.

> I have not tried this idea, and it could cause unit damage or
> malfunction, so I do not recommend the procedure - it is just a point
> for discussion (I have never seen a laptop that would not function
> without a battery, only using external charger, however, the 770 may be
> quite different.)

You will not want to measure the external charger input in any way.
If at all you want to measure the current flowing through the battery pins.
The charger input will run also through the charger logic and might also
toggle other things that would not be toggled in battery mode. If you
want to get an estimate (an exact measurement is more complex) you will
have to simulate a battery and DO NOT ATTACH THE CHARGER then, since it
would try to charge your power supply ;)

> Dave
Cheers
  nils faerber

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