when i turn on the camera and its trying to read the battery the message i get is " cannot connect with battery" i thought it was a defective battery and went out and bought a new one and still kept getting the same message. what can i do ? Does anybody been through this situation from what i hear this is common on the CANNON EOS 7D models only why is that?
I've been shooting with a pair of 7Ds for close to four years now and have never seen such a message. Nor have I heard of a problem such as you describe from any other 7D users (and I'm pretty active on some Internet forums). So, no, I don't think this is a common problem.
If the camera turns on, it must be getting power from the battery. So I am guessing it's just not able to read the on-board battery diagnostics, can't report the battery condition or shot details.
Is it an OEM Canon LP-E6 battery or a third party battery?
Is the battery (or the camera) new, used but new to you, or have you had them for a while and they worked correctly before?
If Canon battery and/or one you have used without problem in the past, I'd simply clean the battery to camera electronic contacts. Just use a few drops of isopropyl alcohol to dampen a clean rag and wipe the contacts lightly... both on the battery and inside the camera's battery compartment. Look closely, too, to be sure there is nothing obstructing any of the battery contacts.
Note: if you are using a Canon BG-E7 vertical grip, also remove that and clean the contacts on both the grip and up inside the camera's battery compartment. If you are using some third party battery grip, that might be the source of your problems. I have heard of issues when using those.
If the battery is old and has been recharged quite a bit, it may be worn out and need replacement.
The OEM Canon LP-E6 have a built-in chip that keeps some data about the battery, that can be read with the camera. Besides the little charge level indicator on the top LCD display, you also can go into the menu, to the third camera setup tab (yellow "wrench" with three dots), and you'll find "Battery info" as the first item. Press "Set" and you'll get information about the battery(ies) condition... charge level, number of shots taken, recharge "condition". Press "Info" and you'll see the battery(ies)'s serial number and the date it was last placed into the camera. You'll also be able to "register" (or delete) the battery from that screen. If the battery is not registered, it's info will be slightly grayed down. Register it now. The word "register" should be highlighted, if the battery is unregistered. All you have to do is press "Set" while on this screen, and the battery should then show registered in the camera (the serial number and date data brighten). Press "menu" to get out of the screen and back to the Battery Info screen. Registering the battery that might cure your problem if you are using OEM Canon LP-E6 batteries. However, some non-Canon batteries do not have the proper circuitry to be registered.
i have two eos 7d camera body and four GENUINE CANON LP-E6 BATTERIES. ihave changed them around but still get the same message that the camera cannot communicate with the battery, so i know its not a faulty battery. apparently there are dozens of people having the same problem, and not just with EOS 7D CAMERAS. I am off to Japan soon for three weeks and am worried that it could ruin what is an expensive holiday of a lifetime. has anyone had this problem sorted and is it a simple repair, or a costly one ?
"... so i know its not a faulty battery ..."
Don't be too sure about this!
I have heard this rumor for a while now,...lately about the 7D. Not in the beginning when I first bought my 7D.
Another rumor floating around is a bad batch of batteries and/or the "chip" inside them.
Of course the standard warning to never use off-brand batteries is a solid one, so guys have made the error go away with one.
Again just what I have heard as it does not effect mine.