Q: How do I tell Lion to disable the LCD screen even when the lid is open?

eww wrote:

 

...to stay in top shape, the machine can be plugged into AC power 95%-98% of the time without any ill effects.

Thank you for your answer eww.

As stated in my message I have just returned to using my external display after the summer, so of course I have used my mac the whole summer on battery power, not as a desktop. I use my mac every day out of home and only use it as a "desktop" in the evenings, so I want to make sure my battery stays in full shape for as long as possible (it's now 2 years old and still pumping juice).

I have often read in mobile phone, other computer, mp3 player (etc...) manuals that to maximise lithium battery durability it is best to rarely leave them fully uncharged or leave them in charge while fully charged. My interpretation of the apple support page stating "all the time" was not as drastic as yours, so I assumed that it confirmed other sources stating not to leave batteries on charge for prolonged periods of time.

May I know what sources you have used to determine that batteries can stay on charge 95% of the time without ill effects?

This of course would make using my mac when at home much less of a hassle, eliminating the need to constantly plug in and unplug my mac (and thus those annoying clamshell interferences).

This said, I still do not understand the reason for totally impeding the use of an external display while on battery power and with the screen open (and deactivated) when performing heavy tasks.

As stated in my message I have just returned to using my external display after the summer, so of course I have used my mac the whole summer on battery power, not as a desktop.

There is no good reason to use the machine on battery power at all times if AC power is available. Doing so just runs up the battery's cycle count and reduces its storage capacity needlessly.

I have often read in mobile phone, other computer, mp3 player (etc...) manuals that to maximise lithium battery durability it is best to rarely leave them fully uncharged or leave them in charge while fully charged. My interpretation of the apple support page stating "all the time" was not as drastic as yours, so I assumed that it confirmed other sources stating not to leave batteries on charge for prolonged periods of time.

No Apple product manufactured in the last ten or fiteen years has continued to charge after full charge is achieved, so there is no danger of leaving an Apple product's battery "on charge" for any longer than it takes to charge it fully — in fact you can't do so. By design, the charging circuitry disconnects automatically at full charge, and doesn't resume charging again (in the case of your MBP's battery) until the battery has gradually drained to less than 95% of full charge — which it will slowly do over a period of a few days, even if the AC adapter remains connected the whole time and the battery isn't drawn upon at all.* This is why you will often see the colored LED on your MagSafe plug lit up green (indicating that full charge has been reached and charging has stopped) when your battery's charge level is only 95%-99% rather than 100%. When the level drops below 95%, the light turns orange to indicate that charging has begun again.

* Every battery is slowly losing charge whenever it isn't being charged, even if nothing is connected to it at all. This is just a fundamental characteristic of batteries.

May I know what sources you have used to determine that batteries can stay on charge 95% of the time without ill effects?

Batteries can't be charged continuously 95% of the time without ill effects. But Apple batteries aren't charged continuously, as I've explained above. The principal authority for my advice to leave your machine plugged in as much as 95%- 98% of the time iwhen it's convenient to do so is the following Apple statement:

"An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge."

If this hypothetical commuter runs her notebook for 45 minutes on the train to work, plugs it in to charge for eight hours at the office, uses it on battery power for 45 minutes on the train home, and plugs it in to charge at home, it will be plugged in 22.5 hours a day, or 93.8% of the time — not counting weekends, when presumably it will be plugged in at home all or most of the time.

Further advice about Apple batteries and their optimal management can be found in these articles (including the one I've quoted from):

http://www.apple.com/batteries/notebooks.html

http://support.apple.com/kb/HT1446

http://support.apple.com/kb/HT1490

Note in the last of these articles (on calibrating the battery) that Apple makes a distinction in its calibration-frequency advice between a machine that is regularly used on battery power (calibrate "every few months") and one that is "very rarely" or never used on battery power except when it's being calibrated (calibrate "once a month").

This said, I still do not understand the reason for totally impeding the use of an external display while on battery power and with the screen open (and deactivated) when performing heavy tasks.

You and many others who have posted in this thread. We'll have to wait and see whether Apple makes the desired change.

Ok, ok, eww your arguments are really convincing!

Especially the inference about the commuter, talk about reading through the lines....

From now I on I'll keep this in mind and not be so worried about leaving my mac on charge while at home! Your argument about the cycle count is pretty reasonable, you wouldn't want your count to increase by more than half while at home for the night...

Thanks for your useful comments.

...And yes, back to the original topic of this discussion, let's hope Apple considers us external monitor people in it's future updates!

Here's the command to make your laptop behave like it did Pre-Lion (courtesy of my friend):

sudo nvram boot-args="iog=0x0"

Works perfectly for me. If it screws up your system, just zap the PRAM next boot (cmd-opt-p-r) and you'll be back to the default Lion state. Or if you can still get into terminal, this command will get you back to Lion's default state as well:

sudo nvram -d boot-args

Enjoy!

Thank you it works!

Go work for apple

Works for me too after reboot.

Seems to do the trick, thank you chenga.8 and your friend!

Like everyone says, it works, Thanks!!!

Thank you so much! It works! You were faster than Apple in solving this problem. You're a real Genius, man!

With this method, does the display stay off even after a restart or only after waking up from sleep?

Works for me, too!  Nice!!!

Enigma, it'll behave the way that it did before Lion:

If you restart or wake it with the lid open, the laptop's monitor will turn on.

If you restart or wake it with the lid closed, the laptop's monitor will stay off until you do a "Detect Displays."

@chenga

Okay so if I want to have the laptops display off after wakeup I always have to close the lid to send it to sleep, then wake him up and only then I can open the lid, so it stays off.

A bit complicated imo if I am using it on an external monitor.

Chenga, that's the old Snow Leopard trick. It doesn't work with Lion - which is exactly what this thread is about.

Seph