Introduction
My digital cameras battery dies quickly when shooting video, about half an hour. And while I can charge the battery via USB, the port will not run the camera itself when recording. So I started looking for a way to power it externally. That led me to dummy batteries, and to some questionable third-party versions. So, is a dummy battery actually worth using?
My camera is an original Canon PowerShot G5 X, released in 2015, so it’s the frame of reference for this presentation. Canon’s official AC Adapter Dummy Battery kit for this camera is no longer manufactured, leaving third-party as the only option. There is one exception, people trying to sell the Original Canon kit for absurd amounts of money on sites like E-Bay and Craigslist. For my use case, it is a hard pass. For my use case and that kind of money, I would get a high end webcam instead.
But trying to not get sidetracked here, I want to explain what a dummy battery is, how it works, and a few things you will want to think about before investing in one.
I’ve heard similar concerns from other camera owners, though the details can vary by camera make and model. And I need to point out that not every digital camera will use dummy batteries in the same way or at all. For this presentation, I am focused specifically on what I found for the G5 X. I will however, point out some of the issues that can apply more broadly.
What is a Dummy Battery
At some point during the design and manufacturing process, my G5X got an external USB port. But this port has limited functionality, it charges the battery when the camera is off. Turn the camera on in play mode and things are good. Turn the camera on in record mode and the USB port stops charging the battery. Not what I would call the best design decision, though I can, to a certain extent, understand it. In 2015 there were a lot more standard USB 2.0 ports out there, which do not have the power handling capabilities needed to run the camera zoom lens and other internals. Proprietary technologies such as Qualcomm Quick Charge could deliver more power to compatible devices, but they weren’t supported by every USB port or device, nor considered when the G5 X was designed.
The solution, another questionable design decision, was the Dummy Battery. Which is basically a battery case with a power cord, meant to go in the cameras battery compartment. Connecting the power cable to an appropriate power source would provide external power to the camera via the battery contacts. Sound simple enough, right?
While this solution is workable, two design issues jump out at me right away. The fact that this dummy battery is replacing a lithium battery which does have internal circuitry, and the fact that there is no battery in the camera when a dummy battery is used. I do want to note that some dummy battery adapters do include internal circuitry, but many do not, and that is something you will want to to check before purchasing.
NB 13L Lithium Battery Construction
The G5 X uses a Canon NB-13L lithium-ion battery. I have several, because I often need to swap batteries while recording. Some are third-party batteries, which will matter later when I discuss the circuitry inside dummy batteries.
The batteries are about 4 × 3 × 1 cm, the size needed to fit the camera’s battery compartment. The Canon NB-13L is rated at 3.6 V, 1250 mAh, and 4.5 Wh. The third-party batteries I use are labeled 3.6 V, 1500 mAh, and 5.4 Wh.
Contacts 1 and 3 are the main power contacts; they’re also the contacts used by the charger. When I opened a Canon NB-13L battery that no longer charged, I found what appears to be a thermistor and two IC chips connected to contact 2 and 4. One IC appears to be a lithium-ion battery protection chip; the other is unmarked. If one of my third-party batteries fails, I may open it up and see what circuitry it contains.
From this tear-down, I can make a few assumptions. Which, with my limited testing, may or may not be valid. The thermistor likely monitors battery temperature. A dummy battery doesn’t contain lithium cells that could overheat, but could contain circuitry that could. Regardless, the camera may still expect a signal from the thermistor. I also suspect the unmarked IC may communicate with the camera identifying the battery type. I’ll need to do some testing to determine whether the camera requires all four contacts for a dummy battery to work properly.
Dummy Battery Kit
Lets take a look at a typical dummy battery kit. This one I acquiredhad decent reviews on Lazada, for what that’s worth
The kit included a USB power adapter rated at 5 V, 3 A. It looks identical to several of my Qualcomm Quick Charge 3.0 adapters, except that it does not have a Qualcomm label. I plugged it in and used my multi-meter to measure the USB Type-A output. Which was 5 V DC, as expected, but the unbranded adapter still looks a bit sketchy.
The kit also included a generically labeled USB camera converter, rated for 5 V, 2 – 4 A input and 4.2 V, 2 – 3 A output. I plugged it into the USB adapter and measured its output voltage: 4.12 V. That’s close to the unloaded voltage I measured from the NB-13L battery. The current output rating is also kind of vague; it would be clearer if the label specified a single rated current.
Finally, the kit included a DR-110 DC coupler. Its dimensions were correct, but it had only two contacts on top. I set my multi-meter to measure resistance between the input jack and the contacts and got 0.00 Ω. Without opening it up, that suggests the coupler is wired straight through. With everything connected, I measured 4.12 V across the two contacts, with no load.
Despite my reservations about the kit and its various issues, the output voltage is close to the expected voltage at no load. Since I don’t have a practical way of measuring current, the next step is to actually try this thing in the camera.
Canon G5X Battery Compartment
I confirmed that the Canon G5 X checks whether the memory card/battery compartment is closed. The compartment has a DC coupler terminal cover that opens to let the dummy-battery cable pass through while the compartment door is shut.
A spring-loaded clip holds the battery in place. To install the dummy battery, press the battery release and remove the NB-13L battery. Slide in the dummy battery, route its cable through the terminal cover, then close and latch the compartment door.
After this the only thing left to do is turn the camera on and check if the Dummy battery is doing its job.
Canon G5X Dummy Battery Test
A few things may be useful to other Canon G5 X owners, and is something to check on other digital cameras. The camera has a small internal backup battery that preserves its settings while you change the main battery. On my 10-year-old camera, the backup lasts about a minute. It also isn’t easy to access or replace, which seems like another questionable design choice.
A minute is enough time to swap batteries, but my dummy-battery test sometimes took longer, and the camera lost its settings. To avoid this, plug in the dummy battery before removing the camera’s battery. Your backup battery may last longer than mine, so your results may vary.
When I turn on the camera, I get a “Battery Communication Error.” Remember the unmarked chip I noticed in the Canon NB 13L battery I took apart earlier. I suspect the camera uses a chip to identify or communicate with the battery, though I can’t confirm that.
The first prompt asks, “Is this a Canon part?” Select No. If you select Yes, the camera displays a message about counterfeit parts and then shuts down.
The next prompt says, “Canon does not guarantee the performance or safety of this battery. Continue to Use?” Select Yes to continue; otherwise, the camera will shut down.
After this point the camera should be running on the dummy battery. Consider disabling power-saving mode to prevent it from shutting down during recording. I had to do this when the camera timed out and shut down first time around.
Some thoughts
Here are some thoughts on dummy batteries for digital cameras. I’ve probably mentioned some of these points already, but I wanted to bring them together here.
For manufacturers: If a camera has a USB port, it would be useful if the camera could run from USB power while a battery is installed. Older USB ports may not have supplied enough power for this, but some newer USB-C and thunderbolt power sources can provide more power. But the camera must support operating from USB power. Even a separate power plug would have been better than a micro USB port with limited funcitonality.
For consumers: Dummy batteries can be difficult to find by mail order, especially for older cameras. Listings don’t always include the information buyers need, so look beyond the promotional photos and check the specifications, which may also be missing. The number of contacts can be a clue: if the original battery has four contacts and the dummy battery has only two, it may lack some communication features. But contact count alone doesn’t confirm compatibility. Some dummy batteries include those features, while simpler, cheaper models may only supply power. Check that the model is suitable for your camera. You may need to contact the manufacturer or ask other owners on forums about their experience.
A dummy battery also won’t provide backup power if its external power source is switched off or disconnected. With a dummy battery installed, there is no regular rechargeable battery in place. Keep that in mind when planning a recording session.
Check the power requirements, too. Cameras can draw more current at certain times, such as when using the zoom lens or changing settings. Make sure the power source and dummy battery provide the correct voltage and enough current for your camera.
Finally, if your camera needs a coded chip in the battery to operate, a basic dummy battery that only supplies power may not work.
Conclusion
I tested a dummy battery kit, and found it functional on my Canon G5 X digital camera. My basic conclusion is that it works well enough for studio use, assuming you have verified voltage, current, and size. However I would advise caution using one out in the field, as it adds something else to keep track of. Also I would advise caution using a dummy battery kit with a power bank. The concern here is the maximum current rating of the power bank, as compared to the maximum current draw of the camera.
I am definitely going to try using the dummy battery in one of my recording sessions. So far my tests have been fairly short term. After a longer session I may revisit this article if I uncover any additional information or gotchas. But for now, its all good!
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