calibrate Mark IV battery

My Mark IV is telling me to calibrate the battery next time I charge it. How is this done?
Thanks for any replies

Slap it in the charger and hold down the button in the middle...

Lights should turn red and start blinking as it discharges and then turn green and blinking as it charges.

As FlyingPhotog said, the process is simple, but I would suggest you wait until the battery is almost depleted, since as part of the calibrating process it will first be fully discharged, and if it is almost fully charged, the calibrate and re-charge can take 8-12 hours. There is no rush to do it, just remember to do it next time you re-charge the battery.

FlyingPhotog wrote in post #14597744
Slap it in the charger and hold down the button in the middle...

Lights should turn red and start blinking as it discharges and then turn green and blinking as it charges.

Flying Photog and Phototeacher: Thanks very much for your helpful replies. Will do as you say and let the battery almost deplete.