Nikon D6 Reference Manual page 1167

2h
Charge
lamps 4h
(green)
6h
Calibration (CAL
ON) lamp (yellow):
L/R
Although calibration is recommended for accurate
measurement of battery charge state, calibration need not be
performed when the calibration lamp flashes. Once begun,
calibration can be interrupted as desired.
•
If the calibration button is not pressed while the calibration
lamp is flashing, normal charging will begin after about ten
seconds.
•
To interrupt calibration, press the calibration button again.
Calibration will end and charging will begin.
When calibration is complete, the calibration and charge lamps
will turn off and charging will begin immediately.
Approximate time needed to recalibrate battery
Under 2
2–4 hours
hours
I (off) K (on)
I (off) I (off)
I (off) I (off)
K (on) K (on)
Over 6
4–6 hours
hours
K (on) K (on)
K (on) K (on)
I (off) K (on)
K (on) K (on)
Specifications
1115