[ltp] Running with line power and no battery

[Christos Papadopoulos]

Unfortunately, there is a lot of folklore on maximizing battery life.

I have seen manufacturers consistently rating battery life in terms of
charge cycles. I can't see how a battery that is constantly drained and
recharged will last very long (in contrast of what crusty old IBM
engineers might believe).

As for leaving the battery plugged in while working on AC, this does
not have a detrimental effect on battery life. The electronics in the
battery ensure that it is never overcharged.

As anectodal evidence, I have heard that periodically (once a month)
letting your battery drain and then recharging will help prolong its
life. I have been trying to do this, but not religiously at all.  The
battery in my X40 is about 5 years old, and will still hold charge for
about 3 hours. And this is with minimal care on my part (i.e., often
plugging back AC in mid-charge).

As for quality, I bought 3-4 batteries on ebay, but all deteriorted
much faster than the OEM products. Not surprising, really.

Christos.

On Fri, Feb 29, 2008 at 12:11:00PM -0500, David A. Desrosiers wrote:
> On Thu, 2008-02-28 at 11:53 -0300, Henrique de Moraes Holschuh wrote:
> > 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).
> 
> I've had Thinkpads consistently for the last 10-12 years, and I've tried
> two distinct usage patterns, both of which seem to have a very negative
> effect on battery life: 
> 
> 1. Plug in the laptop with the battery attached, use it until the
>    "Battery is fully charge" alert comes up, then disconnect AC, and
>    run exclusively on battery. When the low-power alert comes up, plug
>    AC back in and continue to work until the laptop battery is at 100%
>    charge again. 
> 
>    Lather. Rinse. Repeat.
> 
>    Time and time again, across about 7-8 different Thinkpad laptops,
>    this has proved to "kill" a battery before the initial warrantee
>    period of the battery expires (i.e. no longer holds a charge). A 
>    call to IBM for a replacement battery, and you can start all over
>    again. 
> 
> 2. Charge battery to full while on AC, then remove the battery, working
>    only on AC power. When you need to disconnect from AC (or work
>    mobile), plug the battery in and use until the low-power alert comes
>    up. At this point _switch_ the battery for a full-charged second
>    battery.
> 
>    Take the first battery and use the "Battery Rundown" tool to fully
>    drain the battery (usually will provide at least 1 more hour of
>    "life" past the low-battery audible warning alerts). I've usually
>    done this before the end of the day, so I can then plug the laptop
>    into AC with a _fully_ run-down battery, to charge it to full by the
>    morning commute outbound.
> 
> Both of these approaches seem to rapidly kill Thinkpad batteries (direct
> from IBM, not third-party replacements). 
> 
> I spoke to an IBM tech at one point about #1 above, and he recommended
> that as the best way to ensure you don't "prematurely age" the battery.
> He said that keeping the laptop plugged in while the battery was fully
> charged was a bad idea, if I wanted to ensure long life from that
> battery. My own tests confirm and validate this.
> 
> > My 9-cell and bay batteries are at 95% of their design capacity after
> > two years of use (proper storage at 10C).
> 
> 10°C is 50°F... are you storing these in your refridgerator in a ziplock
> or something? Keeping them in a metal container in your basement or
> cellar? 
> 
> 
> -- 
> David A. Desrosiers
> desrod@gnu-designs.com
> Skype...: 860-967-3820
> 
> 
> -- 
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