Canon has released a product advisory for the Canon LP-E6 Battery Pack when used with the LC-E6 Battery Charger.
In short the advisory states that at times the LC-E6 Battery charger will not charge the LP-E6 Battery Pack when this occurs you will notice the orange light blinking rapidly, and usually occurs if the battery pack has not been used for a long time and the battery has been depleted.
- Plug the Canon Battery Charger LC-E6, with the Canon Battery Pack LP-E6 inserted, into a power outlet.
- Wait for 20 seconds.
If during this time the orange lamp blinks once per second, please continue to charge the battery until the green lamp lights up, which indicates a full charge. At this point, the battery is ready for normal use, and there is no need to follow the remaining steps.
If during this time the orange lamp blinks rapidly, please move on to Step 3 of this procedure.
- If the orange lamp blinks rapidly, remove the Canon Battery Pack LP-E6 from the Canon Battery Charger LC-E6.
- Wait for 10 seconds.
- Reinsert the Canon Battery Pack LP-E6 into the Canon Battery Charger LC-E6.
- The Canon Battery Charger LC-E6’s orange lamp should begin to flash slowly (once per second) and charging will begin.
Please note: If the orange lamp blinks rapidly again, please repeat steps 3-5 above. If, after a third attempt, the Canon Battery Pack LP-E6 does not charge, please contact the Canon Customer Support Center for assistance.
- Charge the Canon Battery Pack LP-E6 until the green lamp on the Canon Battery Charger LC-E6 illuminates, signifying that the Canon Battery Pack LP-E6 is fully charged.
The product advisory also mentions in some cases the these symptoms can also occur when trying to charge non-genuine Canon battery packs in the LC-E6 charger.
The full original product advisory can be found via following link