Should I disconnect the power cable when the battery is full? [duplicate]

Solution 1:

If you are asking if you should disconnect your computer from power once the battery if full, the answer is no. If you do so, your battery will keep discharging and charging. The number of times batteries can be charges is limited and if you unplug your computer every time it is full, it will quickly die.

If computer is in such location that it will be almost always connected to power, it may be smart to disconnect it once every two weeks or so and let it run on batteries for a few minutes.

Also, since the laptop is new, it probably uses lithium based batteries. That means that you should avoid completely discharging the batteries because doing so will considerably reduce their lifetime (on older nickel-metal hydride batteries, opposite was true, but they aren't used in laptops any more).

Solution 2:

I would always leave a laptop plugged in whenever I can.

Many modern machines have power save modes and/or can underclock the CPU when on battery power so you will get reduced performance if unplugged. (Although it usually is configurable, but why bother).

Also, batteries only have a finite life, therefore whilst it is good practice to do a complete charge/discharge cycle at least once every so often, the more times you run the battery down from start to finish - the less total capacity you will have.

Solution 3:

From what I have learned reading magazines and also from my personal experience using two different laptops during the last 6 years: If you want to save your (Li-Ion)-battery and keep it as fresh as possible, the best way would be, to take it out of the laptop if the charge is down to about 35-40% and only run your machine with cable. I also tried not to charge or discharge the battery completely. If possible, I tried to charge the battery while the laptop was turned off (or used the docking stations extra power to charge it). Doing so, I did not have to change the battery after 2 years - like most of my colleagues with the same machines were forced to.

Disadvantages are comfort related: You need to know, when you need your battery - it has to be charged 1-2 hours before you take your laptop off the power plug. Other than that, on a sudden power loss, your laptop has no buffer and therefore will turn off.

For my new laptop, I decided, to set the threshhold for battery charging via boot script, so that it will never charge completely and is mainly kept between 40 and 70%. I have an extra button, that will trigger a complete charge of the battery on my desktop. But I basically decided, that the disadvantages in comfort are not worth an extra year or two with my battery.