https://community.usa.canon.com/t5/EOS-DSLR-Mirrorless-Cameras/battery-cannot-communicate-Canon-7D/m-p/9799#M1251 <P>Try cleaning the contacts on the batteries and in the camera with an eraser.</P><P>&nbsp;</P><P>Hope this helps.</P><P>&nbsp;</P><P>Pat</P> Thu, 03 Jan 2013 00:47:46 GMT PatrickE 2013-01-03T00:47:46Z https://community.usa.canon.com/t5/EOS-DSLR-Mirrorless-Cameras/battery-cannot-communicate-Canon-7D/m-p/9777#M1250 <P>I have a 7D about 3 years old now. One battery is original , the other is 6 or 7 months old.</P><P>I upgraded to the latest firmware version 2.0 shortly there after (Don't know if there is a relationship?) one battery could not communicate, the other worked fine. I recharged it and it worked one time more then errors after that. the second battery worked for about 3 more days then it failed to communicate as well.</P><P>&nbsp;</P><P>Questions</P><P>1. Batteries ?</P><P>2. Charger issue causing chip in battery to go bad?</P><P>3. Camera battery sensor chip gone bad ?</P><P>&nbsp;</P><P>Any suggestions?</P><P>&nbsp;</P><P>Thank you</P><P>Jimbo</P> Wed, 02 Jan 2013 20:50:56 GMT https://community.usa.canon.com/t5/EOS-DSLR-Mirrorless-Cameras/battery-cannot-communicate-Canon-7D/m-p/9777#M1250 Jimbo728 2013-01-02T20:50:56Z https://community.usa.canon.com/t5/EOS-DSLR-Mirrorless-Cameras/battery-cannot-communicate-Canon-7D/m-p/9799#M1251 <P>Try cleaning the contacts on the batteries and in the camera with an eraser.</P><P>&nbsp;</P><P>Hope this helps.</P><P>&nbsp;</P><P>Pat</P> Thu, 03 Jan 2013 00:47:46 GMT https://community.usa.canon.com/t5/EOS-DSLR-Mirrorless-Cameras/battery-cannot-communicate-Canon-7D/m-p/9799#M1251 PatrickE 2013-01-03T00:47:46Z