Friday, December 31, 2010

Top 5 lithium-ion battery myths

With the transition from nickel-based batteries to lithium-ion batteries in the past decade, batteries have become one of the most confusing things in our daily life. Nickel-based batteries had their problems. Lithium-ion (or Li-Ion) batteries, which most-probably power up your laptop, phone, music player, cameras and other rechargeable gadgets are always being tossed about in a sea of myths.

Here are five really popular myths (in no particular order) that you should know:

New batteries need an overnight charge
This is completely untrue. If it's a new lithium-based battery, you DO NOT need to completely charge it once. It does have its benefits (will be discussed shortly), but it DOES NOT affect its life or anything.

Why manufacturers recommend this is that the battery will be calibrated properly, and your power indicator will display the right amount of charge. But you can start using your gadgets right away, out of the box. Even if the calibration is wrong (which it rarely is), it will fix itself over use. Really.

Fully discharging it will damage it
This may be true for the older, nickel-based batteries, but ISN'T for the newer, lithium-ion ones. Fully discharging the battery will NOT damage your battery, though it is good for calibration (discussed later).

No problem if you run out of juice. Just get the most done on the next flight and let your computer hibernate on its own instead of shutting it down at 10% charge and wasting a tenth of your power.

Disconnecting the battery when a laptop is plugged in has advantages
It does NOT matter if you let the battery remain in place when your notebook  is plugged in.

Some people used to say that for best results and to extend the life of the battery, disconnect it when the AC power is plugged in. But it is fine even if you shut down the computer, with the battery in and keep the power on. I'll explain why in just a moment.

You need to fully discharge the battery to calibrate it
Calibration of a lithium-ion battery DOES NOT at all require you to discharge it to zero and charge it up again. It is fine if you go down to about 30% to 20% before plugging it back it. Anyway, because I told you earlier, there is no problem whatsoever with it going down completely.

Leaving a laptop plugged in when it's turned off will degrade the battery
This is a huge one. I had this conception since times unknown. I thought that when a computer is turned off, keeping the AC plugged in will reduce the life of the battery, and I made sure to turn the switch off whenever the laptop shut down. No doubt, a ton of people still think this is true. So let me explain everything to completely blow out all the cobwebs of myths in your mind related to this particular myth.

If you have a modern notebook, you most probably know that there is an indicator on it somewhere that lights up when the battery is charging and shuts off when the charging is done. How does this work? The little 'brain' in your lithium-ion battery monitors the amount of charge in the battery. It is behind this turning on and off of the indicator. It also tells your operating system the amount of charge in the battery (so you can use the battery meter).

Thus, when it knows that the battery is full, it simply shuts the electricity going to the battery. The battery is in fact not doing anything at all when it is full and the laptop is running on AC power. To prove this, you can, right now, pull the battery out. If the AC power is connected, the computer should not shut down. And it doesn't! So, the electricity is not flowing through the battery. When the charging is going on, part of the electricity from the wall socket is powering your computer, and part of it is charging the battery. So, when the charging is done, the computer knows it, and the gates are closed. Your battery is NOT being affected at all when the AC cord is plugged in.

So I hope that these myth-busting helped you and cleared out your doubts. Now you can discharge the battery as far as you want, you know how to calibrate it properly, and you know that it is perfectly fine to auto-shutdown the computer even if it is going to be plugged in overnight, among other things.

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See also:
How to turn an AMD Radeon HD 6950 to an HD 6970 (for free)