Chosen Solution
I can’t find anyone with a solid solution online. Batteries that and confirmed to be good and charged will read as empty and my 5D mk II will not operate. Nothing on the rear LCD screen. Only a blinking empty battery on the top LCD. The top LCD comes to life and responds to settings changes (wheel to change aperture or shutter speed) for a second before becoming unresponsive and blinking the empty battery icon. I’ve replaced the internal “watch” battery.
Joel Gautraud , Ensure batteries are indeed good and fully charged. Remove the card and try turning on, then put card back in and try. Still no go, check battery contacts in camera for damage and clean the battery compartment terminals with a pen eraser(a little more grit to remove corrosion/tarnish) or Qtip dampened with 90%+ Isopropyl Alcohol and blow out debri, check and clean battery terminals also, reinsert and try. Still no go try a reset/reboot, link below will take you through the reboot process. Good luck. I hope this helped you out, if so let me know by pressing the helpful button. http://photography-on-the.net/forum/show…
Hi, I’ve had this issue. It turned out to be the battery door microswitch. With the battery in, open the door and press the microswitch to verify if it’s the problem.
This is a very late answer but I hope it will help other users. There is a ribbon cable that runs from the battery “C” contact to the mainboard and it is the only thing that the camera uses to read the status of the battery. If it were damaged the battery would be considered empty no matter what. Otherwise you are probably having issues on the mainboard. By no means it is an easy fix and I’d say replacing the mainboard is actually easier.
I have a Canon 5D Mark ii. It has no problem when I use it with the stock LP-E6 battery. But recently I got a dummy LP-E6 battery box that can connect to external USB-C charger. When I use the dummy battery, the empty battery sign always blinking and the camera can not function. However, if I open the battery cover and close it, all function well. It seems everytime I turn on the camera power switch or USB-C charger, I need to open and close the battery door to “activate” it. A bit annoying but it does work in this week. I could not explain why though. just to share.
