BitDepth 538 - August 22

No matter how fancy your technology might be, it's only useful for as long as the battery holds out...
More power to the people

Inside the sleek shell of your laptop’s battery are the chemical packages that generate its energy lifeblood. Photo by Mark Lyndersay.

The dirty little secret of modern technology is electricity. All those useful little devices we stick in out pockets and hang on our hips depend on batteries to function and as they shrink to ever cuter sizes, there’s less room available to pack cells into the power packs that energize them.
There are all kinds of intriguing technologies lurking on the horizon, but fuel cells, hydrogen cells and even truly odd technologies like microturbines are still far from the kind of tested, commercial status that makes them fit for devices you’d want to hold close to your body.

Improvements in battery technology have been steady over the years, with batteries holding close formation with increasing power needs. Laptops and cell phones get incrementally longer run times not because the devices pull less power (big colour screens, fast processors and wireless connections are power hogs), but because manufacturers have become smarter about how to use the power that’s available.
Most cellphones and all laptops will periodically take a nap when you aren’t using them, screens will dim and eventually go black, nonessential circuitry goes into suspension and only the most essential functions will continue to draw power at the minimum needed to keep the devices on standby.

The default settings of most devices do a good job of increasing battery life, but you can enjoy longer run times of laptops and cell phones by paying closer attention to a few details.
Rechargeables retain electricity and discharge it by storing energy as a reversible chemical reaction between elements stored in the battery’s casing. Charging the battery reverses the chemicals to a state of potential and the chemical reaction resumes as electricity is drained from the cells.

Most of today’s rechargeable batteries use lithium-ion technology, a big improvement on older nickel-hydride and nickel-cadmium batteries.
Today’s lithium batteries don’t have the old cadmium/hydride memory problem, and the old solution to it, regular full discharges and charges, will adversely affect the performance of today’s lithium based cells.
There is, however, one time when you should fully charge and discharge a brand-new lithium battery, and that’s the first time you use it in a new device.

Doing this sends maximum and minimum electrical states to the smarter circuitry in most laptops and cell phones, calibrating them to your battery’s capabilities.
Laptop users can do even more to squeeze more life from their battery. A laptop pulls power to light up the screen, run the processor and motherboard circuitry and keep the hard drive spinning. If you have an optical disk in the CD or DVD drive, that’s going to pull power as well.
You can squeeze more battery life from a laptop by decreasing the brightness of the screen. Depending on where you’re working, you can dim today’s vivid LCD screens quite a bit and still be able to work comfortably. If you aren’t using wireless technologies like Bluetooth and WiFi, turn them off.
If you want to look at a DVD and you have some disk space available, you can use software to make a copy of the movie on your hard drive. This is, strictly speaking, illegal, but fair use laws leans in favour of an owner making a copy for personal use.

Macintosh users should visit the Energy Saver preference pane to fine-tune the behaviour of their systems while running on a battery. There, you can select processor speeds (slower is more frugal with power), how soon the screen should dim and how quickly the laptop will suspend when it isn’t being used.
Windows users have some more choices in the Power Options Properties panel.
Windows supports two levels of suspended operations while using a battery, standby and hibernate. Laptop users should be aware of the difference between the two.
A Windows laptop on standby spins down the hard disk, turns off the screen, idles the processor and uses reduced energy to maintain the information that’s in memory. You can return quickly to work by tapping a key, “waking” the system.

In hibernate mode, the computer goes into a deeper state of slumber, writing the contents of RAM to the hard disk for an added level of security (you’ll need free disk space equal to installed RAM for this to work). A laptop in hibernate mode will take longer to return to working state, but unlike a shutdown, it will retain everything on screen just the way you left it.
If you’re unhappy with the battery life in a device you’re using, remember that all rechargeable batteries have a useful life of around three years, the length of time that the chemical reaction built into them remains optimal, and a constant number of charge and discharge cycles, usually around two to five thousand. Eventually, the numbers will run out on you and replacing your battery will be the only option left.
Just be sure to replace it with a fresh one, not one that’s been sitting on a shelf for a couple of years, quietly dying.

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