Lithium-ion batteries, also known as li-ion batteries, are found in a wide range of portable electronic devices. Many cells phones and laptops utilize li-ion batteries as well as many other portable devices that require a good amount of power.
Recharging a lithium-ion battery properly is crucial to getting the maximum life and power out of the battery. Because these batteries begin to loose their power capacity and recharging abilities as soon as they are produced, you'll want to get every last bit out of your battery before it needs to be replaced.
Charge often - Older electronic devices commonly used Ni-Cd batteries which benefited from deep cycling - allowing the battery to fully drain before recharging. Li-ion batteries on the other hand benefit from being charged often and early on in a fresh cycle. What this means is that a li-ion battery should be charged well before it is fully drained; think about when you plug your cell phone in to charge at night. You don't need to wait until the battery is running low to recharge it if it is a Li-ion battery.
Re-calibration - The exception to the above rule about charging is that about every 30th recharge or so, you should allow the battery to be nearly drained before recharging. This helps to re-calibrate the external battery meter on your electronic device. Your cell phone, laptop, or other device displays the amount of battery life left on it's display usually. Re-calibration ensures that your electronic device is giving you an accurate reflection of the actual battery life left since the last recharge.
Infrequent use - If you haven't used the li-ion battery in a while, you'll want to make sure you only charge it to about 60% of it's maximum charge. The reasoning behind this is that li-ion batteries that aren't used often are at risk for permanent capacity loss; a fully charged li-ion battery in storage will lose a far higher percentage of capacity then a partially charged li-ion battery. This is especially true when stored at warmer temperatures.
Laptop li-ions - This is for only li-ion batteries in laptop and notebook computers. Most portable computers can function fully without the battery connected when they are connected to an external power supply. During long usage periods, the heat from the laptop can affect the battery itself, removing the battery during long periods of externally powered use can protect the battery.
Temperature control - Li-ion batteries last the longest when they are recharged and stored in cool temperatures. Some people store extra li-ion batteries in a refrigerator, although most batteries will be alright stored and used in temperatures below 77 degrees F. Fully charged li-ion batteries loose capacity far quicker then partially charged li-ion batteries, so if you don't use it often it is best to keep it partially charged and stored in a cool location.
Total depletion - If your li-ion battery reaches it's minimum voltage, usually below 3 volts per cell, the battery is considered dead and won't recharge at all. This is why it is important to never allow your li-ion battery to fully drain, it should be plugged in from time to time.
Li-ion batteries when taken care of and recharged properly can last quite a few years. All li-ion batteries begin to loose permanent capacity from the time they are produced, their storage conditions play a big part in just how long they will last. You should recharge your li-ion battery as often as you can until the charge it holds is too low to be useful for daily use. Only then should you purchase a new li-ion battery.