Canon MARK IV User Manual (en)

Charging the Battery
With Car Battery Cable CB-570 (sold separately), you can connect the 
charger’s car battery cable socket (<DC IN> terminal) to your car’s 
cigarette lighter socket.
When recharging the battery this way, be sure that the car’s engine 
is running. If the car engine is off, disconnect the car battery cable 
from the cigarette lighter socket. If you leave the car battery cable 
connected to the cigarette lighter socket, it may drain the car battery.
Do not use a transformer for the car with the battery charger.
Battery charging from a car battery is possible only with a 12 V DC 
or 24 V DC car battery in a minus-grounded car. The shape or 
dimensions of the cigarette lighter socket in certain cars might not be 
compatible with the car battery cable.
This indicates that you should calibrate the battery so that the correct 
battery level is detected and the camera’s battery level indicator can 
display the correct battery level. Calibration is not a required 
operation. If you want to just recharge the battery, you can let the 
battery start recharging automatically after approx. 10 sec. If you 
want to do the calibration, press the <CALIBRATE> button while the 
<CAL/CHARGE> lamp is blinking in red. The Charge level indicator 
will blink in red and the calibration (power discharge) will start.
After the calibration is completed, the battery will start recharging 
automatically. Note that the less depleted the battery, the longer the 
calibration will take. The <2h>, <4h>, and <10h> figures on the side of 
the Charge level indicator respectively indicate the approximate number 
of hours it will take to complete the calibration (power discharge). If the 
<10h> indicator blinks in red, it will take approx. 10 hours.
After the calibration is completed and the battery is totally drained, it 
will take a further 2 hours to recharge the battery fully. If you want to 
stop the calibration before it is completed and start recharging the 
battery, remove the battery from the charger and attach it again.
Use the Car’s Cigarette Lighter Socket to Recharge the Battery
The <CAL/CHARGE> Lamp Blinks in Red