The most adequate method to do a full discharge (100% to about 3%) consists of the following procedures:
Fully charge the battery to its maximum capacity (100%);
Let the battery “rest” fully charged for 2 hours or more. You may use the computer normally within this period;
Go to your Power Options in the Control Panel and configure the automatic hibernation to hibernate the computer when it reaches 3% of capacity. If you cannot set the 3% value, just set the minimum value you can;
Leave the computer discharging, non-stop, until it hibernates itself. You may use the computer normally [...]