External power and non-Nikon batteries on the Nikon D3100

_DSC8718, originally uploaded by afiler.

The Nikon D3100 is a great camera for the price, the bottom end of Nikon’s DSLR range. Being a bottom-end camera, a few things are missing, like an external power connector. I’m using this camera in a fixed setup for slide scanning. The 1080p live view makes an excellent way to preview slides on an HDMI monitor, but this will drain the battery quickly. One option is to use the Nikon EP-5A, which is basically a battery-like plug for the camera, which then attaches to the Nikon EH-5A power supply. This will run you about about $108 at B&H. A spare battery will run you another $50. None of the third-party batteries available apparently work in the D3100, as Nikon puts some sort of inkjet cartridge-style money-sucking chip inside their batteries. (I’m sure the vast camera accessory factories in China are working to overcome this issue).

It turns out the answer to both these problems is a third-party D3100 battery grip, $20something from Amazon.


The left-hand battery slot in the D3100 will take the $8 third-party batteries, as the camera is happy as long as it can see a Nikon battery when it starts up. I decided to add a barrel type power jack so I can power the camera off a power supply. I suppose it’s possible that all these infidel non-Nikon parts could cause the camera to explode, so don’t try this at home, kids.


The battery grip contains a circuit board that runs the whole width.


I attached the barrel plug to the left-hand (“infidel”) battery slot. In this photo, Green is – and White is +. Most DC power supplies are center-positive, and so I used that scheme here. I picked a spot for the barrel plug that puts it right against the battery slot so it can’t easily pop out. I carefully drilled a hole in the case, squared it off, and hot glued it in.

It works perfectly. You can even remove the genuine battery once the camera is booted.

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18 Responses to External power and non-Nikon batteries on the Nikon D3100

  1. tommykay says:

    What are the specs on the wall wart you used? The batteries are 7.2 volt, but I wonder what the acceptable range is. Now, I could fool with my own camera, but if you already did the testing…..

    Nice work on the DIY, by the way. Brilliant.

  2. afiler says:

    I’m not sure what the ideal voltage is, but I’ve used a couple different power supplies in the range of 6-9V. I accidentally put 12V into it once, and while it didn’t appear to work, it also didn’t hurt. The Nikon EH-5 power supply puts out 9V, so I think I’ll stick with that.

  3. chalk says:

    Hi, Great work, this could be exactly what I’m after. I’m trying to run a D3100 as a time lapse in the field for months at a time and having trouble sorting out suitable power for it. If I can connect this directly to a 9V battery and charge that from a solar panel I might just be in luck. You mentioned you’ve been using a 9V supply, is this from a battery or from a wall charger? I was hoping to connect it to this http://www.ebay.com.au/itm/dual-outputs-5V-9V-12V-USB-Super-Capacity-Recharge-Li-ion-Battery-/260987821526?pt=US_Batteries&hash=item3cc4161dd6

  4. afiler says:

    That’s very cool. I used a wall wart, but I see no reason a battery like that wouldn’t work.

    By the way, I found the remote control interface pretty easy to work with — to shoot, I just use an Arduino (overkill for this, but it works) to pull the focus (half-press) and shutter (full-press) pins on the remote to ground.

  5. Tamas says:

    Great job! does the camera work if you take out the en-el14 batteries (both geniune and 3rd party) and the only source is the 9V supply? (eg. PSU or extra battery)

  6. Frank says:

    Hi, you Can use a 7 Amp/hr 12v gell battery, take 4 or 5 diodes, put them in serial with the + line.
    Every diode takes off 0.6 volts, so all in all, well under 10 volts.
    I use this construction for my Musical Fidelity V-Dac, to create a very clean power supply, works fantastic.
    These batteries are available for about 20 euro’s/dollar.

    Regards, Frank

  7. Jack says:

    Hi, love the DIY! So you wired up a 9V DC connector to the left hand battery compartment, can this compartment be used still? And can you run the camera completely off of DC power? Or is it constantly charging the battery’s?

  8. afiler says:

    Yes, the left-hand compartment is still useable. There’s plenty of extra space in the battery grip. Once the camera is booted, you can remove the batteries and it will continue to run off the DC supply.

  9. Dave says:

    i see that there is 5 pins IIIII
    did you solder the 2 on each side xxIxx
    or just the ends xIIIx

    i cant tell from the photo. thanks

  10. afiler says:

    If those are actually two separate pads on the ends, I didn’t see that, since they were already covered in solder. So if that’s the case, then it must be xxlxx.

  11. Artis says:

    Camera does not recognize the power source even if i solder power wires there.
    I use LM317 to obtain 7,4 stady power supply from my car battery.
    Any other solution on how to start the camera with external power source?

  12. afiler says:

    It still requires a real Nikon battery (with the special chip) be installed. The battery doesn’t have to be charged up — it can draw some charge from the external power supply, just enough to power the chip to identify itself to the camera. Once the camera is powered up, the battery can be removed.

  13. Artis says:

    Do we have to use original NIKON battery or EL 14 other types to start the camera?

  14. afiler says:

    Yes, to power up it needs a real EN-EL14 battery from Nikon. Other batteries don’t have the chip that the camera requires.

  15. Jeff says:

    Very nice. You could hook this up to an adjustable buck converter and set the voltage at whatever you wanted (7.4 or 9v). I am trying to imagine a way to get the profile of this down so that it is as small as the battery by itself… :(

  16. kriss says:


    this what i’ve been looking for
    is it still working until now?.. do you have any issue about it or it just perfectly stable?
    what ampere on your 9v ac adapter?..


  17. afiler says:

    I’m still using it, and it’s still working fine. The adapter I use is 1A, but I think I remember using it with a 300mA adapter too.

  18. Wiktor says:

    I’m going to test it tomorrow!

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