Use USB power banks to get hours more shooting time out of your camera

Feb 9, 2017

John Aldred

John Aldred is a photographer with over 20 years of experience in the portrait and commercial worlds. He is based in Scotland and has been an early adopter – and occasional beta tester – of almost every digital imaging technology in that time. As well as his creative visual work, John uses 3D printing, electronics and programming to create his own photography and filmmaking tools and consults for a number of brands across the industry.

Use USB power banks to get hours more shooting time out of your camera

Feb 9, 2017

John Aldred

John Aldred is a photographer with over 20 years of experience in the portrait and commercial worlds. He is based in Scotland and has been an early adopter – and occasional beta tester – of almost every digital imaging technology in that time. As well as his creative visual work, John uses 3D printing, electronics and programming to create his own photography and filmmaking tools and consults for a number of brands across the industry.

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The more features that get packed into each new generation of cameras, the less time batteries seem to last. Things like liveview, gps, WiFi, NFC, VR/IS, and a host of other doohickies just drain them faster than they used to. Even if your camera doesn’t feature superfluous battery draining features, other things can kill them quickly, too. Shooting video or timelapse with long exposures, for example.

The obvious choice is simple. Take a bunch of spare batteries. But what if you want more time without having to worry about interrupting your sequence to swap out a battery? That’s where USB power comes in. This video from David at 30Five Millimeter shows you how you can get USB power with your DSLR or mirrorless camera with just a dummy battery and a $5 cable.

YouTube video

Of course, there are commercial USB power solutions available, too, like the TetherTools Case Relay. This is something we use ourselves when we’re filming at shows.  At Photokina last year, a 20,000mAh Anker battery managed to last us an entire day shooting video with the Sony A7II. Each night, we just topped it back up to full, ready for the next.

But it’s possible to get similar capabilities at a much lower price point. All it requires is a dummy battery, and an inexpensive 5v USB to 9v cable. Do make sure you get one that outputs no more than 9v. A few of those cables go up to 12v, and that will probably fry your camera. While most internal batteries in DSLRs and mirrorless cameras are 7.4v, cameras can usually handle anywhere between 7-9v.

Parts List :

The barrel adapter is down there as a maybe as it really depends on which dummy battery you get. Some will already have the appropriate 5.5mm barrel connector. Others, like the Nikon EP-5B (EN-EL15 dummy battery) will have a proprietary plug. And you’re probably going to have to go at it with a pair of scissors and a soldering iron to get the plug you need.

Essentially, though, there’s not really much to the whole setup. Insert the dummy battery into the camera. Plug the 9v end of the USB cable into the dummy battery, with an adapter if need be. Then plug the other end into the USB battery and you’re good to go.

The SmallRig Cheese Plate, 1/4-20 Cold shoe Adapter and the Velcro is optional but wise. It lets you easily mount the battery on top of your camera, so that you can keep it out of the way.

Skip this bit if you’re not into maths

There is a little issue with the maths in the video, though. In the video, David mentions that he’s using a 10,000mAh Anker battery. He also mentions that the battery in his Panasonic Lumix G85 is 1,200mAh. So, he divides 10,000 by 1,200 to get an answer of 8.33. So, 8.33x more power, right? Well, not exactly.

The problem is, that’s 10,000mAh at 3.7v (the voltage of the cell inside the power pack). The Camera’s battery is 1,200 mAh at 7.4v (it’s a 2 cell battery). That means the USB power pack has 37Wh (Watt hours) of total power. The Camera’s battery has a little under 9Wh. So, total power is only a little over four times as much. Not 8.33.

When this 37Wh of power is converted to 9v, that means 4,111mAh. And that’s assuming 100% conversion efficiency, which isn’t physically possible. 92% efficiency is usually a pretty good benchmark. And the voltage here is being converted twice.

So, 92% of 37Wh to convert 3.7v to 5v is 34.04Wh. 92% of 34.04Wh to convert 5v up to 9v is 31.32Wh. That leaves around 3,500mAh. Still a little under 3x as much power as the original camera battery.

TL;DR the maths

Basically, a 10,000mAh USB power bank is going to give you around 3x the life of a 1,200mAh camera battery. Not 8.33x as suggested in the video.

Still, triple the life isn’t to be sniffed at, though. It’s still a great increase over the standard batteries supplied with cameras. And 10,000mAh USB batteries are inexpensive, easy to get hold of, and can be used for so much more than just keeping your camera powered.

On any given location shoot, I have at least 6 USB batteries ranging between 8,000mAh and 12,000mAh with me. Always handy for charging phones and tablets, or powering a WiFi router – you can’t beat having your devices connected to each other in the middle of nowhere sometimes.

It would be nice to leave the extra DSLR batteries at home and just have everything run off USB. So, I’ve already ordered myself a couple of those USB to 9v cables for my existing dummy batteries.

What do you use to prolong your camera’s life when away from power to recharge? Do you just take a bunch of spare camera batteries or do you have another solution?

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John Aldred

John Aldred

John Aldred is a photographer with over 20 years of experience in the portrait and commercial worlds. He is based in Scotland and has been an early adopter – and occasional beta tester – of almost every digital imaging technology in that time. As well as his creative visual work, John uses 3D printing, electronics and programming to create his own photography and filmmaking tools and consults for a number of brands across the industry.

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13 responses to “Use USB power banks to get hours more shooting time out of your camera”

  1. David Mattos Avatar
    David Mattos

    [FACEPALM] Can’t believe I forgot to take the voltage into consideration…thanks for the catch on that one, and the share!

    1. Kaouthia Avatar
      Kaouthia

      We’ve all done it at some point. :D

  2. Jyi Offer Avatar
    Jyi Offer

    Does it factor in the reduction in amps between 5v up to 9v ?
    How much current does the camera require?

  3. Julian Cataldo Avatar
    Julian Cataldo

    GX80’s USB FTW

  4. Nicolas Racine Avatar
    Nicolas Racine

    I was wondering if I could power a speedlite the same way. I’ve been looking into this for a while without success. Anyone knows?

    1. Kaouthia Avatar
      Kaouthia

      I doubt it. You’d need to have a go-between battery that could dump a lot of current at once (essentially the USB pack would charge that, and then that would power the flash). I tried modifying a Yongnuo YN560-II to use 5v USB batteries, and even at minimum power, it couldn’t draw enough current to charge the flash up.

      Ultimately it would just choke and die after the internal capacitor was empty.

      1. Nicolas Racine Avatar
        Nicolas Racine

        Yes, I figure the amperage is not high enough on those USB power packs. A flash needs about 10A, and they give out 4-5 at most. I don’t want to use a “8AA batteries power pack”, but It’s the price to pay for being cheap and using speedlites (not because I am cheap, because I like them). :-)

  5. chrisTopher A Avatar
    chrisTopher A

    Would this work to power a continuous LED light that uses a Sony L-series battery (like the Neewers or Aputure Amaran 198)? The output is 7.4v at 2amps. If so, why isn’t everybody doing that?

    1. Paul K Avatar
      Paul K

      It works and I’ve tested it myself, but check my post for the specific 7.5v usb to dc adapter link. Less chance of feeding the LED panel too much power and works so much better than carrying more L-series batteries. When I can carry say a 20K+ Mah external battery with two ports to power my camera and lighting for whole event to shoot. My Yongnou YN300 Air has a dc power input or takes Sony L batteries. I’m glad I opted for this model to have both power options.

      I’d have to agree with you. I rather go this route as buying a Godox PB960 for my speedlite is quite bulky and it, itself is about 4000 or so Mah.. Just need to find a way to either go from usb to 5 DIN for the speedlite/ flash.

  6. Paul K Avatar
    Paul K

    I found a similar hack / work around for sony cameras, in my example the A7ii with a dummy plug. Just due to the amazon reviews for that step up usb adapter outputting to 9v and worrying that’s too much than the stock output. I found this usb that outputs to 7.5v and found that it does not over heat during my testing. It also powers my Youngnou YN300 air LED panel for video. For anyone worried that your expensive gear is getting too much volts and breaking later down the road, I would recommend this instead.

    7.5V USB power cable for My Weigh Ultraship 55 Scale by MyVolts for $10.
    link – https://www.amazon.com/gp/product/B00GC0WZLY/ref=od_aui_detailpages00?ie=UTF8&psc=1

    It ships out from Sweden, but if you can pay additional $5 for faster postage it might get faster to you than a week and half. Or find the same item listed under a different store page with prime shipping, but it’s going to cost $40.

    I also would only use the better branded and built external battery packs; Anker, Aukey, RAV, etc. I tried it with a Kamashi and either the pack doesn’t keep the power consistently or something, but the camera would reset here and there with that one.

    I use the following battery pack, for 10K mah and fits in your fist, it’s pretty weight savings and saves me from having to swap out at least 3 NPFW50 batteries when I shoot 3 hour restaurant events every week. A missed shot opportunity due to swapping out batteries is costing me more than this simple hack, so for me, it’s very well worth it.

    Anker PowerCore 10000
    https://www.amazon.com/gp/product/B0194WDVHI/ref=od_aui_detailpages00?ie=UTF8&psc=1

  7. hemant vaishnav Avatar
    hemant vaishnav

    Hey John
    I want to do this similar hack for Godox Speedlight Flash using PV-nx socket, it’ll be great if you help me out?

  8. Jose A. Ramirez Avatar
    Jose A. Ramirez

    I wonder if there are camcorders batteries with a USB power output. In my case i have an HDMI to SDI converter can be powered with a powerbank. The think is it an extra work to charge camera battery and the power bank. If i could have a centralized power source would be great.

  9. Ganesh L Avatar
    Ganesh L

    Hi All, For specifically charging cameras, I have developed a power bank prototype that can be customized to different voltage and current requirements. It is a DIY project. Do look into my youtube video to get an idea.

    https://youtu.be/xeFokAu-39k

    Ganesh Laxmanmurthy