Battery problems

[Mikkel L. Ellertson]

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On 03/12/2012 03:47 PM, Michael Cronenworth wrote:
> Mikkel L. Ellertson wrote:
>> It is not for conditioning the battery. It is to update the battery
>> calibration.
>
> Most do this at boot so if Robert did a full power reset he should
be fine. There is no need to run a utility or manually run the
battery down.
>
> Older, Ni-Cad, laptops did have calibration utilities in their
BIOS. No longer the case with Li-On.
How do they calibrate on boot? I know they can read the battery
status on boot, or battery change, but that is just getting a report
from the circuit in the battery. The circuit in the battery needs a
power cycle to recalibrate.

Now, Ni-Cads did not have or need this circuit, as they have a
predictable voltage curve, so you can check the status by checking
the battery voltage. Lithium-Ion batteries do not experience a
voltage drop until they are almost dead. So you can not determine
the battery status by reading battery voltage.  You have to ask the
battery about its state.

This circuit in the battery is the reason you have to go through
extra steps when rebuilding a Li-Ion battery pack to get full
performance. Some (most?) of the battery circuits remember the last
battery curve even after removing the power. So you have to tell the
chip to delete the saved battery state, and recalibrate for the new
batteries.

Mikkel
- -- 
Do not meddle in the affairs of dragons, for thou art crunchy and
taste good with Ketchup!
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