1 Calibrate It

Calibrate the battery based on its usage. “Under the normal usage, batteries should be calibrated once every three months,” Wentzel said. “However, a battery that is rarely discharged fully should be calibrated about once a month.”

To calibrate, turn off all hibernation or suspend modes, then charge the battery until full and unplug your notebook from the wall. Once the battery has completely drained and the laptop has automatically shut off, connect the AC adapter to the notebook again and charge it completely. Turn back on your power management settings, and the calibration will be complete.

Also, avoid battery-conditioning utilities. “They were really more applicable to previous generations of battery technology,” Wentzel said.

2 Don’t Overdo It

Remove your laptop’s battery if it’s going to remain plugged into AC power for more than two weeks straight. It’s unnecessary to plug in while you’re connected to the wall.

3 Dial Down the Brightness

“It seems obvious, but you need to turn down the display brightness while running off of a battery,” Wentzel advised. “I’ve done tests and have seen 15 to 30 minutes of saved battery life between a display at low brightness and at high brightness. Airplanes are usually dim environments, so it’s easy to keep the display brightness low.”

4 Hibernate is Better than Suspend

“The big thing that most people miss is using the display’s Suspend or Hibernate modes that come with their machines. Note that Standby keeps the notebook’s state in memory and uses some power, while Hibernate stores the machine’s state to disk and uses almost no power.”

5 Turn Off What You’re Not Using

If your machine has infrared and you don’t use it, disable it. Same thing goes for Bluetooth. As for Wi-Fi, be sure to toggle the radio off when you’re doing work that doesn’t require you to be online. In our tests we’ve seen as much as an hour difference in unplugged runtime between systems with their Wi-Fi connection turned on and off.

6 Big Downloads Equal a Big Hit on Endurance

Windows users are constantly reminded to install Automatic Updates. These can wait until you find an outlet. “Avoid doing big downloads and software installs while running on a battery, if you can, and save them for later when you are plugged in,” Wentzel suggested. This includes e-mails with big attachments and updates to programs such as iTunes. 

7 Store it Properly

Leaving your laptop exposed to high temperatures, in excess of 77 degrees, such as in a hot car, can accelerate the deterioration of the battery. “Store lithium-ion batteries between 68 and 77 degrees with a 30- to 50-percent charge.” 

8 Have a Backup Plan

While proper conditioning will certainly help your notebook’s battery live a longer life, it will eventually wear out. “After a certain number of charge-discharge cycles, batteries will stop taking as much of a charge,” Wentzel said. “You can’t revive a worn-out battery.” Consider carrying a spare battery so that, when one wears out, you can quickly put your notebook into Hibernate mode and make the swap.