Battery performance | check your EOS camera battery
My Canon EOS 5D Mark IV is asking if the inserted battery is original or not. What are the implications of my answer? - Photography Stack Exchange
Canon EOS 7D Battery Error Fix | The Virtual Venesect
How can I fix a "Cannot communicate with battery" error on Canon 7D? - Photography Stack Exchange
Amazon.com : Battery Grip Kit for Canon EOS 7D Digital SLR Camera Includes Qty 2 Replacement LP-E6 Batteries + Vertical Battery Grip + More!! : Digital Camera Accessory Kits : Electronics
A Canon 7D Mark 1 issue – “Cannot communicate with battery” – Stephen Monro's blog