MBP: Better to Charge it Or Let Battery Drain During Normal Usage?

[rekhyt]

Is it better, during normal usage, for example at home, where you could either charge your MacBook Pro or let the battery drain until it is used up (5%, ...).

Some people say that letting the battery cycle is the best option, yet other people, including my friend who had lost many many cycles even though he had attempted precautions (Dim screen brightness until one block remained, wireless off, bluetooth off) had said that having your laptop plugged in as muchas possible is the best option, as there would be no cycle change.

What is the best option?

 

[Tonsko]

This website is an ideal resource:

http://www.batteryuniversity.com/

It's pretty long and involved. It depends on your type of battery. I suspect the battery in a MBP will be Lithium-Ion or Lithium-Polymer:

http://www.batteryuniversity.com/parttwo-34.htm

...and for the really lazy, a quick summary:

Lithium-ion has not yet fully matured and is being improved continuously. New metal and chemical combinations are being tried every six months to increase energy density and prolong service life. The improvements in longevity after each change will not be known for a few years.

A lithium-ion battery provides 300-500 discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible. Instead, charge the battery more often or use a larger battery. There is no concern of memory when applying unscheduled charges.

Although lithium-ion is memory-free in terms of performance deterioration, batteries with fuel gauges exhibit what engineers refer to as "digital memory". Here is the reason: Short discharges with subsequent recharges do not provide the periodic calibration needed to synchronize the fuel gauge with the battery's state-of-charge. A deliberate full discharge and recharge every 30 charges corrects this problem. Letting the battery run down to the cut-off point in the equipment will do this. If ignored, the fuel gauge will become increasingly less accurate. (Read more in 'Choosing the right battery for portable computing', Part Two.)

Having said that, that's only one site, but it does seem to be grounded in research at least, rather than just passing on experiences. It's advice I've always followed.

HTH

 

[fcortese]

I had to have my battery replaced last year because it wasn't holding a charge. I was told that it needs to be periodically drained completely and then recharged. I know have a monthly reminder through iCal to do a battery drain/recharge go to the apple web site and type in batteries and you can get this info and set up your iCal reminder to boot.

 

[GGJstudios]

This should answer most, if not all, of your battery questions: Apple Notebook Battery FAQ