Canon EOS 7D Battery Error Fix

Or, How to Beat Canon’s Money Grab

Canon 7D with main battery removed.

Canon 7D with main battery removed.

I purchased a factory refurbished Canon EOS 7D digital SLR camera several years ago. It’s worked great and I’ve been pleased with it—and I’m still using the original proprietary battery pack. Several weeks ago I’d picked it up after several months of disuse and tried to turn it on. The camera was dead. I wasn’t too surprised, so I pulled the battery and put it into the charger. After a charge I put it back into the camera. Still wouldn’t turn on. Pulled the battery again and placed it back into the charger, which thought it was fully charged. Hmm.

After reinstalling the battery and futzing around a bit I finally got the 7D to turn on, but with an error message on the display: “Cannot communicate with battery. Use this battery?” I selected ‘Yes’ and was able to use the camera, but there was no feedback as to the battery’s charge level on the status display. It turns out this is a common problem with the camera, and the most common solution is to return the unit to Canon with a $250 payment for repair. Although the problem seems widespread Canon has not enacted a recall. This is an unsatisfactory situation and seems to me like a money grab by Canon.

I wondered whether or not the battery contacts (on the battery itself or the contacts within the camera) had become fouled. I removed the main battery from the camera as well as the memory backup coin cell (a CR1616) from the battery compartment. Next I dug out my trusty can of Caig Laboratories Deoxit D5 (available at most fine electronic parts retailers, or at Parts Express and MCM Electronics) and some cotton swabs. Here’s what I did to restore the camera’s normal operation:

1)      Remove the main battery from the camera and look at the flat side. You’ll see two silver rectangular contacts side-by side. There are also two side-by-side slots halfway between the left and right sides on the same end of the battery. There are contacts within these slots as well.

2)      Wet one of a cotton swab with Deoxit. It should be damp when you’re finished, but not dripping wet. DO NOT SPRAY DEOXIT DIRECTLY INTO THE CAMERA OR ONTO THE BATTERY.

3)      Look into the camera’s battery compartment, using the location of the contacts on the battery itself to guide you as to where to apply the Deoxit. NOTE: when looking into the camera you’ll see a lot of copper-colored circles at the bottom of the battery compartment, as shown in the photo above. THESE ARE NOT BATTERY CONTACTS. The contacts will be on the wider, flat side of the compartment down close to the spring. Wipe the four contacts with Deoxit.

4)      Now wipe the battery contacts with Deoxit. For the contacts in the slots, you may have to pull and shape the cotton on the swab to make it thinner and flatter. Alternatively, you can take a corner of a paper towel and fold it several times, spray it with a little Deoxit and work the towel into the slots.

5)      Re-insert the battery into the camera, but pull the white latch to the side with one finger and hold it while you repeatedly push the battery in and allow the spring to pop it back out again. Do this fifteen or twenty times to help polish the contacts and ensure they’re coated with Deoxit. When finished remove the battery and set it aside for ten minutes or so.

6)      Take the opportunity to remove the CR1616 coin cell from the battery compartment and change it if you’ve never done so. With the carrier that holds the coin cell out of the camera you can see two sets of silver contacts in the slot. Wipe those with Deoxit, then carefully insert and remove the battery/carrier a few times. (This battery’s contacts aren’t as robust as the other set so be careful.) When finished, insert and leave the coin cell in the camera.

7)      The last step is to insert the main battery and try turning the camera on. You may still have to futz around with the controls a bit for the first turn-on cycle; I didn’t.  You should be greeted by a prompt to change the time and date.

Fortunately this routine allowed me to resuscitate my camera and one week out it’s still working. Now what could possibly have caused the issue? My theory is that some small amount of gasses produced by the battery’s internal chemicals may have escaped and fouled the contacts as the battery slowly discharged inside the camera. Perhaps this is why it’s recommended to remove the batteries from your electronics when they’re not being used for a period of time. In the future I intend on following that advice.

If this helped you please pass it on. Why should anyone spend $250 that they don’t have to?

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Filed under Photography

10 responses to “Canon EOS 7D Battery Error Fix

  1. Just found this page, my 7D popped up with the same exact problem/error about a week after you posted this. Using Canon batteries and the grip. Any errors since? I’ll try this, I’m still using the camera and it’s guesswork on how much battery life I have left – it seems like it’s using much more battery life then normal though. (I’ve read about the $250 fix also on other forums, many times the user doesn’t even know what is replaced/fixed!). It is amazing this error is a widespread issue on this model, Canon should recall this problem, if it’s from the firmware updates or some odd flaw, they need to address it.

  2. vvenesect

    KanyesSkirt, I just checked the camera and it’s still okay. I’ve read that the camera will work if you can get it to start without battery communication, but it will drain the battery at a higher rate. I agree; Canon should own up to the problem. It’s getting them a lot of bad publicity.

  3. I have just run into this problem. unfortunately the cleaning contacts solution did not fix it.
    I was reading elsewhere that there is a problem with the battery. I have 4 genuine Canon batteries of various ages. They all have the same problem in my canon 7d.
    They all work perfectly well in my canon 5d III. Why is it so?
    This problem only occured after I let a battery discharge to exhaustion in the canon 7d. I have a feeling that this is the problem.
    Either it fries some internal connection with corrosion, or the software has a melt-down because of the discharged battery.
    It has been suggested that taking out the cr1616 and letting the camera “lose” its memory may fix this problem

    • vvenesect


      You can certainly try removing the memory battery. I did that in the course of my troubleshooting and, in fact, replaced it with a new one. As of today the camera is still working well with my fix. Perhaps I lucked out.

      • I’ve tried that and the freezer trick – no joy. I guess the Camera is 4 years old. and I expect to be hit with a $250+ bill. Almost not worth it when I can buy an EOS M with EF adapter for $390

  4. Hi. I have to say that you saved my money. It really works. I had to do it twice, but it worked. for the second time I put a kitchen’s paper between the battery and the contact cleaner, and I spayed directly, for the camera compartment I did what you say. thanks a lot for your help. I have had this problem almost one year

  5. It works!!! Thank you very much!!!

  6. Short circuit by screw!!! SOLVED: Canon 7D “will not communicate with battery”

    • vvenesect

      I’m not sure if this completely solves the problem, or whether there are a number of things contributing to the issue–but there seems to be mounting evidence that Canon needs to do two things. First, admit there’s an issue and be upfront with their loyal customers. Second, fix the problem(s) at no charge to their customers. It looks as though Canon is trying to take a page from Apple’s playbook: Deny until you cannot deny any longer. The question is how many customers will still be loyal and continue using their products?

      • Customers do not know what the problem is and get paid for the repairs. If you will be to identify more cases of problems with just a screw tightened enough, the chance to make free repairs after the warranty service will be higher.

        Until yesterday, I found only one message that bolts are gone and the author has put newer, but not searched, which could disappear old. Hopefully after my posts will begin to change the situation.

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