Proper laptop battery usage guide
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First of all it's necessary to unfold a myth that persists in
many peoples head.The battery memory effect.
In lithium-based
batteries this is in fact a myth, it only applies to older
Nickle-based batteries. So fully discharging and charging the battery is
completely useless and even harmful as we will see below.
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The modern lithium
battery can be charged regardless of its current percentage, given that it has
absolutely no negative effect in its performance.
Many laptop users have
this question and we will answer it right now:
The answer is: YES and NO, it depends on the situation.
The answer is: YES and NO, it depends on the situation.
Having a battery fully
charged and the laptop plugged in is not harmful, because as soon as the charge
level reaches 100% the battery stops receiving charging energy and this energy
is bypassed directly to the power supply system of the laptop.
However there's a disadvantage
in keeping the battery in its socket when the laptop is plugged in, but only if
it's currently suffering from excessive heating caused by the laptop
hardware.
So:
- In a normal usage,
if the laptop doesn't get too hot (CPU and Hard Disk around 40ºC to 50ºC) the
battery should remain in the laptop socket;
- In an intensive
usage which leads to a large amount of heat produced (i.e. Games,
temperatures above 60ºC) the battery should be removed from the socket
in order to prevent unwanted heating.
The heat, among the
fact that it has 100% of charge, is the great enemy of the lithium battery and
not the plug, as many might think so.
Full battery discharges (until laptop power
shutdown, 0%) should be avoided, because this stresses the battery a lot and
can even damage it. It's recommended to perform partial discharges to capacity
levels of 20~30% and frequent charges, instead of performing a full discharging
followed by a full charging.
Laptop batteries
contain a capacity gauge that allows us to know the exact amount of energy
stored. However, due to the charging/discharging cycles, this sensor tends to
be inaccurate overtime.
Some laptops include
in their BIOS, tools to recalibrate this battery gauge, which is nothing more
than a full discharge followed by a full charge.
So to calibrate the gauge, it should be performed, in every 30 discharge cycles, a full discharge non-stop , followed by a also, non-stop, full charge.
So to calibrate the gauge, it should be performed, in every 30 discharge cycles, a full discharge non-stop , followed by a also, non-stop, full charge.
An inaccurate gauge
can lead to the fact that the the battery capacity values are are wrong. The
battery may report that it still has 10% of capacity when in fact it has a much
lower value, and this causes the computer to shutdown unexpectedly.
Discharge (or charge) cycles consist of using all that battery charge
(100%) but not necessarily all at once.
For example, you can use the laptop for some minutes in a day, using half its capacity e then fully charge it. If you did the same thing in the next day, it would be counted a discharge cycle and not two, so it may take several days until a full discharge cycle is completed.
For example, you can use the laptop for some minutes in a day, using half its capacity e then fully charge it. If you did the same thing in the next day, it would be counted a discharge cycle and not two, so it may take several days until a full discharge cycle is completed.
The most adequate
method to do a full discharge (100% to a minimum of 3%) consists of the
following procedure:
1.
Fully charge the
battery to its maximum capacity (100%);
2.
Let the battery
"rest" fully charged for 2 hours or more in order to cool down from
the charging process. You may use the computer normally within this period;
3.
Unplug the power cord
and set the computer to hibernate automatically at 5% as described by the image
sequence below (click images to enlarge). If you cannot select 5%, then you
should use the minimum value allowed, but never below 5%;
4.
Leave the computer
discharging, non-stop, until it hibernates itself. You may use the computer
normally within this period;
5.
When the computer
shuts down completely, let it stay in the hibernation state for 5 hours or even
more;
6.
Plug the computer to
the A/C power to perform a full charge non-stop until its maximum capacity
(100%). You may use the computer normally within this period.
After
the calibration process, the reported wear level is usually higher than
before. This is natural, since it now reports the true current capacity that
the battery has to hold charge. Lithium Ion batteries have a limit amount of
discharge cycles (generally 200 to 300 cycles) and they will retain less
capacity over time.
Many
people tend to think "If calibrating gives higher wear level, then it's a
bad thing". This is wrong, because like said, the calibration is meant to
have your battery report the true capacity it can hold, and it's meant to avoid
surprises like, for example, being in the middle of a presentation and suddenly
the computer shuts down at 30% of charge.
To store a battery for
long periods of time, its charge capacity should be around 40% and it should be
stored in a place as fresh and dry as possible. A fridge can be used (0ºC
- 10ºC), but only if the battery stays isolated from any humidity.
One must say again that the battery's worst enemy is the heat, so leaving the laptop in the car in a hot summer day is half way to kill the battery.
One must say again that the battery's worst enemy is the heat, so leaving the laptop in the car in a hot summer day is half way to kill the battery.
If you intend to
purchase another battery, it's recommended that you do it only when the current
battery is very degraded. If it's not the case, the non usage of a battery
leads to its degradation.
If a spare battery is purchased and won't be used for a long time, the above storage method should be used.
Besides that, when purchasing a battery you must pay attention to the manufacturing date.
If a spare battery is purchased and won't be used for a long time, the above storage method should be used.
Besides that, when purchasing a battery you must pay attention to the manufacturing date.
BatteryCare allows you
to have the control over the discharge cycles number, and when this reaches 30
(or other configured value), it notifies you that it's time to perform a full
discharge in order to keep the battery gauge calibrated.
Like this, it's guaranteed to always have the correct capacity values reported by the battery.
Like this, it's guaranteed to always have the correct capacity values reported by the battery.
Besides, when using
the battery, there's the possibility to suspend some Operating System features
that help degrading the autonomy (only in Windows Vista or higher):
- Windows
Aero, the theme that allows for visual effects like window transparency,
requires graphics card acceleration, which obviously will help decreasing the
battery lifetime;
- SuperFetch,
ReadyBoost and SearchIndexer are three Windows Vista (and higher)
services that, even in battery mode, are using the hard disk a lot and increase
total power consumption, thus decreasing battery lifetime. Suspending these
services has absolutely no negative impact on the performance or security of
the system.
These
features are resumed once the laptop is plugged in to A/C power.
