Some of you may not have noticed, but both the latest MacBooks Air and MacBooks Pro promise even 30 days battery life when at rest.
Of course, when it comes to laptops, getting there is not very simple.
To make this possible, what OS X does put machines in hibernation mode (standby mode), which differs from a simple standby / rest mode (sleep). When this happens, all of the laptop's RAM content is transferred to your hard drive so that random access memory can be temporarily turned off.
This means that when the user opens the cover of the MacBook, the system needs a certain amount of time to rewire the RAM and pull that data from the HDD. In general, the process takes 5 to 15 seconds, which is still quite noticeable. The screen even lights up almost immediately, but what appears is a screenshot of its last state before hibernating, so it is "useless".
Fortunately, users can change this behavior using some Terminal commands. It is located in the / Applications / Utilities / folder of the system, and it is worth noting that the following commands will ask for the user's administrator password to be executed. Therefore, this is not recommended for beginners.
sudo pmset -a standby 0
Increasing the time to enter hibernation
sudo pmset -a standbydelay 21600
The above 21600 is the number of * seconds * that the system takes to exit the mode sleep to standby. In other words, 21600 divided by 60 in 360 minutes, that is, 6 hours. Likewise, if you want to switch to 12 hours, then you should use 43200.
By default, OS X is configured to do this after 70 minutes (1h10), that is, if you change the configuration today and then want to return to the original state, just run the command above changing the 21600 for 4200 seconds.
Checking the current configuration
pmset -g |grep standbydelay
And a final comment: anyone who owns a MacBook Pro with Retina display or any other custom Mac with a solid state drive may not have to experience this aforementioned delay, not least because the process of transferring data from SSD to RAM ends up being much more fast. So be sure to consider this, as the change obviously results in less battery life.
(tip from Cleri Aloisio Azevedo, via Ewal.net)