[ltp] Running with line power and no battery

[Henrique de Moraes Holschuh]

On Thu, 28 Feb 2008, Arno Trautmann wrote:
>> Every non-ancient ThinkPad works fine without a battery, AFAIK.  But I'd
>> still rather use a screwed-up 5s-of-charge-only old battery than run the
>> laptop without any secondary power source it can count on.
>
> Just yesterday I read the thinkwiki, which tells me:
>
> ???Battery health
>
> Batteries, especially of the modern Li-Ion type, wear out quicker when  
> they hold a large charge or are subject to higher temperatures (see 
> above).
>
> If you use your laptop at a desk, reduce battery wear by maintaining an  
> appropriate charge level. When possible, remove Li-ion batteries while  
> operating from AC as the notebook gets hot enough inside for that to  
> damage the battery in the long run, even if charging is stopped.???
>
> [http://www.thinkwiki.org/wiki/Maintenance#Battery_treatment]
>
> So I mostly run my X61s without battery and never got any problems.

ThinkWiki is correct.

But as always, there is another side to the issue.  How much is a battery
worth over the price of your X61s?  I'd just get the cheapest battery to
always have something on hand I can use as needed without any concern.

In fact, I have a 6-cell, a 9-cell and a bay battery for my T43, and the
last two ones are kept at 40% @ 10 degrees Celcius for 99% of their lives,
while the 6-cell almost never leaves the laptop battery bay.  I still have
about six hours of battery time when I need, and one hour and a half of
battery time on a battery pack I use as much as I need.

Even when the laptop is in my desk, which has a damn good UPS feed, I still
keep the battery inside because I often want to sleep-to-ram and remove the
laptop to work on another part of the house (and I do NOT trust
sleep-to-disk).

Yes, such usage pattern damages that particular battery slowly.  It is at
about 50% of its design capacity after two years of use (I usually keep it
in the 30% to 85% charge range, and it is usually at 37C on the charger, 30C
on the cells).  My 9-cell and bay batteries are at 95% of their design
capacity after two years of use (proper storage at 10C).

[Dammit, I need to find a way to type in the proper degrees Celcius symbol
on mutt. C is Coulombs, not Celcius degrees, but you get the idea I am not
talking about Coulombs above, I hope]

One thing one learns fast is that trying to preserve batteries to a point
that it starts interfering on how free you are to use your laptop just
doesn't pay off.  You should care for them, of course.  But not to the point
it starts giving you trouble.

If for your usage pattern, removing the battery while on AC doesn't cause
any problems nor extra risk to the laptop, by all means do remove it.  It
will last a bit longer.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh