Thursday, January 21, 2010

Charge A Lithium Ion Battery

Lithium ion batteries are highly efficient and widely used in laptops, cell phones and similar devices. When you charge a lithium ion battery, ions are forced into the anode and cathode of the battery by the electric current. The process of charging is simple, provided you follow some simple precautions to insure safety and to maximize the life of the batteries. Always check the battery manufacturer's specifications before you charge a lithium ion battery. Improper charging may create a serious fire hazard.


Instructions








1. Use a battery charger designed for lithium ion batteries. A charger for lithium batteries should be able to deliver 3.8 to 4.2 volts per cell. Never use a low power (trickle charge) system. This can cause lithium to adhere (plate) to the anode and oxygen to be generated at the cathode, producing an extremely flammable mixture. Lithium ion batteries come with an internal "safety board" that automatically terminates charging when the current rate drops to 10 percent of the initial charge rate, indicating the battery is fully charged. The best chargers also feature a timer you can set to stop the charging process at a preset time.


2. Place the lithium ion batteries in the charger and make sure it is plugged in. Depending on how much power remains in the battery it will take two to six hours to fully charge most lithium ion batteries. As an added safety precaution, set the timer to avoid the possibility of overcharging.


3. Charge the batteries at the appropriate voltage setting. To maximize the charge, the voltage should be set at 4.20 volts per cell. However, you can extend the useful life of lithium ion batteries by using a slightly lower setting (about 4.10 volts for most lithium ion batteries). This will give you about an 80 percent charge.








4. Charge lithium ion batteries to about 40 percent before storing them for long periods. It is not good for the battery to bring it to full charge and then store it, since this will reduce the battery's useful life. To further extend battery life, recharge stored batteries to the 40 percent level every few weeks (check the battery specifications for recommended times).

Tags: lithium batteries, about percent, batteries charger, check battery, lithium batteries