Canon EOS-1DX Instruction Manual page 33

None of the Charger's Status Lamps Light Up
If the <CAL/CHARGE> lamp lights up but none of the status lamps
do, the battery's internal temperature is outside the required 0°C -
40°C / 32°F - 104°F temperature range. The battery will start
recharging when the internal temperature is within 0°C - 40°C / 32°F
- 104°F.
All Three Charge Level Indicators Blink
If any of the following occurs, remove the battery from the charger
and consult your dealer or nearest Canon Service Center: All the
Charge level lamps blink in green, all the Calibration (Discharge)
status indicator lamps blink in red, or the indicators blink alternately
in red and green (including the <CAL/CHARGE> lamp).
Also, if a battery other than the Battery Pack LP-E4N/LP-E4 is
attached to the charger, the indicators will blink in red and green
(including the <CAL/CHARGE> lamp) and the battery cannot be
recharged.
The charger cannot charge any battery other than the Battery Pack LP-E4N/
LP-E4.
When two battery packs are attached to the charger, the battery attached
first will be charged first, then the other battery will be charged. Although
one battery can be recharged and another calibrated at the same time,
two batteries cannot be recharged or calibrated at the same time.
It is best to perform battery calibration when the battery is nearly
exhausted. If you try to calibrate the battery while it is fully charged, it can
take as long as approx. 15 hours to calibrate and then fully charge the
battery.
Charging the Battery
33