[ltp] Re: ThinkPad Batteries

Thu, 13 Nov 2008 13:40:03 +0000

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Amazing replies!!! Thanks very much to all!!!It's all crystal clear now...

2008/11/12 Michael Karcher <karcher@physik.fu-berlin.de>

> Am Mittwoch, den 12.11.2008, 22:13 +0000 schrieb Daniel Castro:
> > echo 30 > /sys/devices/platform/smapi/BAT0/start_charge_thresh
> > echo 80 > /sys/devices/platform/smapi/BAT0/stop_charge_thresh
> > i though that it would charge up to 80% and then run on battery until
> > it gets to 30%, then charge again to 80% and so on... isn't that
> > what's explected?
>
> These thresholds just inhibit charging: Your laptop decides to start
> charging the battery if the charge falls below 30% (by using it on
> battery or by self-discharge, the latter needing a very long time), and
> keeps charging until 80%. At that point, charging is stopped, but that
> does not mean that discharging is startet. The battery is just left
> alone. There are ways to force using battery power on AC, see the
> documentation, but this is not recommended on normal use.
>
> The sense of the stop_charge_threshold is that charging the last 20% of
> the battery is done with high cell voltages (as the cell voltages rises
> during charging) and the battery cells are stressed more if the voltage
> is higher. The sense of the start_charge_threshold is to keep the
> battery at even lower average charge (and voltage) and avoid
> charging/discharging cycles.
>
> Regards,
>   Michael Karcher
>

-- 
________________________

Daniel Castro, M.Sc.
+353 083-318-2058
dancasmo@gmail.com
castromd@tcd.ie
________________________

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Amazing replies!!! Thanks very much to all!!!<div>It&#39;s all crystal clear now... <div class="gmail_quote">2008/11/12 Michael Karcher &lt;<a href="mailto:karcher@physik.fu-berlin.de">karcher@physik.fu-berlin.de</a>&gt; 
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Am Mittwoch, den 12.11.2008, 22:13 +0000 schrieb Daniel Castro: 
<div class="Ih2E3d">&gt; echo 30 &gt; /sys/devices/platform/smapi/BAT0/start_charge_thresh 
&gt; echo 80 &gt; /sys/devices/platform/smapi/BAT0/stop_charge_thresh 
</div><div class="Ih2E3d">&gt; i though that it would charge up to 80% and then run on battery until 
&gt; it gets to 30%, then charge again to 80% and so on... isn&#39;t that 
&gt; what&#39;s explected? 
 
</div>These thresholds just inhibit charging: Your laptop decides to start 
charging the battery if the charge falls below 30% (by using it on 
battery or by self-discharge, the latter needing a very long time), and 
keeps charging until 80%. At that point, charging is stopped, but that 
does not mean that discharging is startet. The battery is just left 
alone. There are ways to force using battery power on AC, see the 
documentation, but this is not recommended on normal use. 
 
The sense of the stop_charge_threshold is that charging the last 20% of 
the battery is done with high cell voltages (as the cell voltages rises 
during charging) and the battery cells are stressed more if the voltage 
is higher. The sense of the start_charge_threshold is to keep the 
battery at even lower average charge (and voltage) and avoid 
charging/discharging cycles. 
 
Regards, 
 &nbsp;Michael Karcher 
</blockquote></div> -- ________________________ Daniel Castro, M.Sc. +353 083-318-2058 <a href="mailto:dancasmo@gmail.com">dancasmo@gmail.com</a> <a href="mailto:castromd@tcd.ie">castromd@tcd.ie</a> 
________________________ 
</div>

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