&D can't communicate with battery but works

[Kajito Nagib]

I turned on my 7D today and I got an error message that says "cannot communicate with battery. Use this battery?" I select yes and the camera works fine but I can't get any info on battery life. Yesterday I use it for a few minutes it worked fine.I tried 3 different batteries all of them were recharged and I still get the same message. I'm about to go on vacation and now I'm wondering if I should rent a 7D to be on the safe side. Any ideas what's going on?

[Kajito Nagib]

I just turned it on and it worked without the error message then I shut it off the camera and turned it back on and got the same message again.

[Chris Soucy]

Sounds like the camera circuitry which communicates with the battery has gone intermittent.

Whether that is the start of a general creeping paralysis or not you'll only find out by flogging it till it drops dead (or not).

I'd send it in for repair soonest, before you go away and rent a replacement unit in the meantime.


CS

[Kajito Nagib]

thanks Chris.

[Ervz Tia]

Hello! Any update on this issue I just got got this error after 3 years of normal operation.

[Kajito Nagib]

The error message "cannot communicate with battery" went away on its own and the camera has been working fine now for a few weeks. I have no clue what's going on.

[Seth Bloombaum]

Dirty terminals? A little schmutz could be intermittently interfering.

Just speculating...

[Charles Newcomb]

Are you using Canon batteries, or aftermarket batteries? I had that same issue with a Wasabi battery, which I have since relegated to use only in my field monitor. If you're using Canon batteries and it's doing that, I'd strongly consider sending the camera in to Canon Service.

I had a Canon battery just quit taking a charge recently. I tried different chargers, no difference. It's kaput. I think the battery was only 2 years old. Bummer, dude.

[Kajito Nagib]

I only use Canon batteries.

[James Holtzman]

7D owners, I hope this fixes your problem, don't waste your time resetting the camera, wiping battery contacts, putting it in the freezer, etc. It could be from a bad battery, but very likely is from a screw that came loose inside the camera, please read on:

I didn't mention in posts on other forums, I've been an instrument technician for more than 40 years and don't have a problem going into the camera and making the repairs, I've done so on other Canon cameras and Canon lenses. Service manuals don't always give the order of which screws need to be removed. I wouldn't know in the case of the 7D because I've never seen a service manual.

We have been led to believe that the cause of the problem was due to a screw making the ground connection on one of the circuit boards had come loose and was floating around inside the camera. The first symptom is that we get the famous error as described on the subject of this thread. If the problem goes long enough unfixed, not only can we not read the battery level, I've heard that even if the camera is turned off, the battery will discharge over a very short period of time. Worse than that, if the loose screw shorts between some traces on any of the boards, catastrophic results will occur, then circuit boards actually will have to be replaced.

I held off repairing my camera, simply because I didn't have the time.

I put out the request on multiple forums asking which screws need to be removed. As it turns out, a total of eight screws need to be removed to remove the bottom panel of the camera. Six screws on the bottom and one screw on each side of the camera. I took my camera apart, found the loose screw, applied a tiny drop of #242 blue loctite and put the screw back where it belonged. It should have been loctited in the first place, never was, I have heard that Canon is charging people as much as $300 for a repair that never should have been necessary, because of a factory defect. I took a photo showing the bottom removed, it is obvious as to where the screw is missing from. The screw was jammed up into the camera, a couple taps on a table top loosened the screw. There are three types of screws, three of the screws on the bottom have a blue thread lock, probably loctite. Three of the screws on the bottom do not, they are the same size. The two screws on the left and right side near the bottom of the camera are a little longer than the bottom screws, don't get them mixed up.

I would attach my photo showing where the screw is missing from but don't know how to attach a photo to this post. I've seen similar photos elsewhere on the web.

We owe the help to John Clark
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John made a 15 minute video, it is on youtube showing exactly what he had to do to perform the repair.

This video is being shared with John's permission:

https://www.youtube.com/watch?

v=DQaejgJM1Rc&list=UU2MDDaPI8sz97ybNJ2mZDyg

As I mentioned, if you let this problem go too long, it may only get worse, damaging more boards and costing you more money.

And, yes, I did ask others which screws were to be removed, I didn't have the time to experiment, I had other priorities.

Jim, owner of many Canon products

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