Before calibrating it's important to determine what the voltage of your battery is. To do this you need to access "Diagnostic Mode." Follow our BionX Diagnostic Mode instructions to determine your battery voltage and then return here to proceed.
If you see that your battery does have the correct voltage and is fully charged, hold down the MODE button for 20 seconds - wait for a loud beep - then release the MODE button. If it doesn't work, retry the above steps a second time. Sometimes it takes 2 runs through to get it to grab.
If you do not get a correct voltage reading, you either have an older battery, a battery which has not been taken care of properly and has therefore lost some of its capacity, or a case specific issue that needs further looking into.