IT, Photography, Travel

DIY Canon AC-Adapter

November 30th, 2011 Posted in Photography

I’m a big fan of time-lapse projects. But there always are 2 limitations. Memory Card space and Battery life. The memory card space is easy to overcome. Connect your DSLR with laptop/pc/mac and store the images there, or buy a bigger memory card. 16GB can go a long way with medium-sized JPG’s. Battery life is the main problem in my eyes. Using a Battery grip, 2 Canon batteries only go for about 6-10h. Setting the review-time to 0s can save a load of battery power, but it still doesn’t extend the battery life long enough.
I have tried putting 6 Eneloop AA batteries in the grip. This babies kept the camera running for about 25hours. A serious improvement, and great for mobile time-lapses.

I wanted to be able to plug my camera in a power outlet, so it could virtually run forever. Canon has such an AC-Adapter. The ACK-DC20. But at a price of £76 I had no intention of buying it. In stead, I built one myself with things I had in my ‘storage’ and spent less than 2euro. From scratch you’d be able to build this for about 15-20eur.

You will need:

  • A 12V AC-DC adapter with an output power of 1 Ampere (1000mA)
  • An old Canon battery
  • Some soldering equipment
  • A piece of PCB
  • wires
  • An LM7808
  • Two 10 uF 16V Capacitors
  • A female adapter-plug

This ‘tutorial’ will guide you building the AC-Adapter for a Canon 400D, but since all canon’s have the same 7.4V batteries this will work with any other Canon DSLR and probably any other brand of DSLR.

Step 1: The battery

The first thing you have to do is open up an old Canon battery. I had a few old ones laying around which couldn’t keep a decent charge. Cut the battery open along the lines. Be careful that you don’t cut too deep into the battery inside. start with the corners and gently cut deeper till it opens.
You’ll have something like this:

Take the batteries out and cut them from the separator. Keep the separator containing the metal plates. We’ll need that upon assembly.

Step 2: The scheme

The soldering is fairly straightforward. I am using an LM7808 Voltage regulator. This chip keeps a constant DC voltage between 7.9 and 8.1V. This is perfect for the camera as it can take up to 8.1V as you can see in the Image. The green circle highlights the cable-gutter on the camera.

This voltage regulator costs less than 1 Euro and can power up to 2Amps, The camera doesn’t use more than 1Amp so it doesn’t need any cooling.

Pin layout of the LM7808:

The schematics:

As you can see it’s fairly straightforward. The 12V gets connected to the IN pin. 1 capacitor is placed between the IN and GND for ripple-deduction which might come from the adapter. Another capacitor is placed between the OUT and GND for a stable voltage. This is not mandatory but I did it anyway.

Step 3: The soldering

1: Solder the female adapter-plug onto a piece of wire. This can be a short or long wire, as you please. The female plug you see on the right.

2: Take a small piece of PCB which will fit inside the battery shell and solder the LM7808 voltage regulator onto it so it can lay flat.

3: solder the capacitors (optional but recommended) following the scheme. These capacitors are polarised. the short leg needs to be connected to the GND, the longer leg to the +12V and +8V for the next one. Don’t get this the wrong way or they will explode and/or catch fire!

4: Finally solder 2 short wires onto the PCB to connect the output (+8V) and Ground (GND) to the battery separator and solder the long wires to the IN line of the LM7808 and the ground wire to the GND pin. In an adapter, the +12V usually comes from the middle pin. the outer ring is usually the ground. Be sure to check this. Below you can see my print layout. The separator will be in the middle, so place the components on the outsides.

5: Check if it’s working properly. Check the input and output voltages. Make sure you have no short-circuits.

6: Fit everything inside the small battery case

7: Cut a small hole in the battery box’s side top for the cable to come out. Look where the cable gutter in your DSLR is and make it fit.

8: Glue to box close.

9: All done!

Step 4: The adapter

As I said the adapter should have an output current of 1000mA or more. A 12V adapter is recommended, but it can be anything from 11V up to 20V (although 12V is the best choice here). You probably have one of those babies laying around the house. Using a higher voltage adapter will make the LM7808 become warm or hot when under full load. I’ve tested full load (continuous shooting in Medium JPG for 1 minute) and the battery case had come skin-warm but far from hot!

The result

As you see the cable fits perfectly in the camera and the battery grip. Both options work perfectly. The lid closes on both without any problems.

All in all this is a fairly straight-forward build which costs you about 2EUR if you don’t have to buy a 12V Adapter.

Let me know what you think or have any questions :)

  1. 28 Responses to “DIY Canon AC-Adapter”

  2. By Greg Lumley on Dec 1, 2011

    Hi Stefan, thanks so much for taking the time to post this useful information!

    I’m trying the same thing with a canon 350D using an LM3717 and the camera does not respond at all. I have tested another battery in the camera and that works.

    I fear it could be something wrong with my circuit building although my meter tells me it’s working.

    Anyway do you know if the “T” terminal has any relevance when doing this… I was under the impression that the “T” terminal was used only when charging.

    Given that you have not wired it I’d say not but thought I’d ask

    This is probably a dumb question but I’m sitting here scratching my head and quite desperate to find a solution :-)


  3. By Stefanvds on Dec 1, 2011


    If I’m not mistaken the 350D takes the same batteries as the 400D. I do think the T pin is your problem though. When you measure the voltage between the + and the – on the battery you get about 8.3V. Between the + and the T you also get 8.3V, so the T and the – are both Ground (GND).
    During the construction of this thing I haven’t paid any attention to the T pin. It seems in the cheap Canon Batteries I bought from ebay they were already connected internally. I’d say 2 things: 1: Connect the T and – so they both are on the GND. 2: Use a LM7808. It’s so much smaller and safer! 8-8.1V is absolutely perfect for the camera. At which voltage have you set your LM317? Also, did you use the 1Amp package?

  4. By Greg Lumley on Dec 1, 2011

    Hi Stefan, thank you so much for the advice… what I failed to mention is that I broke the PCB off thinking that since the batteries used it it would no longer be necessary and could even complicate things.

    This was before I saw your tut :-(

    The original tutorial I found was using a Canon 300D battery which in the pics only seemed to have two terminals.

    I tried connecting the T to ground but that did not work either… I’ve ordered a new cheap battery off eBay and when that arrives I’ll try again this time leaving the PCB intact!

    I’ll also be sure to use the 7818 this time as well!

    Thanks so much for the advice!


  5. By Stefanvds on Dec 1, 2011


    Make sure you use the LM7808 (not LM7818 like you wrote).

    Keep me posted on your progress. Let me know if you run into any problems!

  6. By Malcolm on Jan 17, 2012

    Stefan, have just built one of these for my 400D. The only thing that I would suggest is that anyone building this checks the datasheet for the regulator they purchase. The one I purchased from RS in the UK had the Input and Outputs pins reversed to that shown in your tutorial – lucky for me it didn’t damage the camera.

    Once I had checked and wired it correctly it powered my camera just fine :)



  7. By Ilidio Pires on Sep 25, 2012

    Hi Stefan,

    Greetings from Portugal :)

    First, thank you for this fantastic and useful information…
    Recently, after visited your blog, I decided to build my 350D AD-DC adapter using your tutorial. It works perfectly, so, I decided to make a tutorial based in yours, but in Portuguese. I placed a link to your blog. Hope you don’t mind.
    You can check it at http://www.ilidio…
    On top menu, select Dicas-> Adaptador AC-DC para 350D.

    Ilidio Pires

  8. By Johan on Oct 21, 2012

    Hi Guys!
    Saw that it was a while some wrote here. Hope its still active.

    Is it still the same procedure with the new EOS 1100D and others?
    Got my self a battery from Mediamarkt, but it wouldn’t charge in the stock charger. Apparently some charging restriction to the stock batteries.
    Is this affecting your build as well?? Or just the charging??

    Looking for a good AC-DC supply for looong studioshooting,

    Nice tutorial BTW..

    Ha de gott!

  9. By Stefanvds on Jan 11, 2013

    It looks like the LP-E10 (the battery for the 1100D) is also a 7.4V battery with 3 pins. Therefore this should work as well.
    Please do try and let us know! The technology should work for all 7.4V batteries… :)

  10. By Myk on Apr 9, 2013

    Hi. Thanks for your tutorial. I’m building this AC-DC adapter but used the KA7808 transistor. Do you think it’s the same? I’m building it for a Canon G5 which uses BP-511 Batts and i’m wondering if you used the circuit inside the batt or did you solder the output direct to the output terminal of the BP-511? Thanks!

  11. By Stefanvds on Apr 10, 2013

    The KA7808 should be the same. the only thing you need to make sure is the PIN layout of this transistor might be different from the LM7808. When you google for the KA7808 you find datasheets showing the pin-layout, so make sure it’s right.

    I think the BP-511 is another one of those batteries where the 2 ‘extra’ pins do nothing at all really. Just open it up and have a look where they go. I reckon you could just make the circuit, place the 8V on the + and – and the camera should work.

    I have a 50D using the same BP-511 batteries but I have not yet made this for that camera.

  12. By Myk on Apr 10, 2013

    Thanks! I had it working last night, just needed a heat sync on the transistor as it became too hot. other than that everything’s working fine. Excellent and very useful tutorial btw. Cheers from the Philippines!

  13. By Stefanvds on Apr 10, 2013

    What have you been doing with the camera when the transistor became too hot? on my 400D it doesn’t get hot at all, but I do use it for slow time-lapses like 1pic ever few minutes and use a 12V adapter. In that case you don’t need a heat sink at all. but if you plan doing filming or using the camera intensively I guess it might become hot. A lot depends on the input voltage you use. The higher the input voltage, the hotter the 7808 will become…
    Feel free to share a picture!

  14. By Myk on Apr 10, 2013

    I was testing it like a shot with flash every second. I was using a variable DC output adapter that i set to 12v, on the cover it say 2000mA max, i think that may be where the problem comes from?

  15. By Stefanvds on Apr 10, 2013

    The flash will draw a lot of power. did you notice a fast/slow flash reload or the same vs normal battery? I think that’s a test as heavy as it gets… You can find temperature sheets in the datasheets as well. usually they are fine up to 60 degrees. but again, if you can put a heat sink in, just put it in.

  16. By John on Apr 12, 2013

    Hi, do you think 8.1V of output are higher for a 1100D, which works at 7.4V?

  17. By Rex Concepcion on Jul 12, 2013

    Hi Stef,
    This article is so amazing. Im just wondering if this will work on my EOS 600d? 7.4 v

    Thank u from the Philipines!

  18. By Stefanvds on Jul 12, 2013

    The 600D looks to have a much more complicated battery.
    I’ve googled a bit and the 600D uses a for AC power.
    This ACK-E8 AC unit outputs 7.4V and 2 Amps.
    I would not use this exact technique as I used for this.
    If you know something about electronics, you should check out the LM317

    You basically change my diagram with this diagram:

    The 5k variable resistor shown on that website should be replaced with a 1.2k ohms resistor. that will give you 7.5V output and should be safe!

  19. By Rex Concepcion on Jul 12, 2013

    Wonderful! Thank a lot Stef!

  20. By Gerhard on Dec 6, 2013

    Interesting stuff – thanks for posting!

    I’m working on a DIY power adapter for my 550D/T2i. I bought a cheap lp-e8 battery form which I only used the case and the connector, used a variable power source with 7.4 V and connected this directly to the + an – pin on the Battery case. (nc for the D and T pin!)

    Unfortunately the camera didn’t power up with this configuration – maybe it’s due to the missing D and/or T pin?

    Does anybody have experience with an LP-E8 adapter?


  21. By Ferry on Nov 13, 2014

    Recently my friend pass me his 1100D, but I noticed there are using 4-pin 7.4V battery …are they [-][-][+][+] ?


  22. By Stefanvds on Nov 13, 2014

    Can’t really find anything. I dont think it would be
    but probably

    it does look like a very small battery. It would be very difficult to make this project work inside that tiny shell.

    try to measure the voltages with a voltage meter.

  23. By Arie on Nov 16, 2014

    Is this adapter works like the lanparte LP E8 dummy battery? (

    Can I apply it like in the tutorial from Chris Andrew? (

    Would you mind to make schematic as an alternative for the Lanparte LP-E8 DC Coupler. Or please give some reference, cos’ I already tried to google it, but no clue at all.

    Thank you so much. Greetings from Indonesia.

  24. By Stefanvds on Nov 17, 2014

    It looks like for the LP E8 you need to use the outer pins.
    I’d advise you to buy the dummy on Ebay, it looks like a cheap alternative. The LP E8 battery is very small so it will be almost impossible to make it the way i did with the 400D because of space issue.

  25. By Arie on Nov 17, 2014

    I see. Thank you very much. :)

    you rock! \m/

  26. By Szabolcs on Feb 7, 2015

    I have made a custom battary for my 350D and put a 10K Ohm resistor between T and -.
    It works great.
    I think there is a 10K resistor in the original battery case also between the T and – terminals.

  27. By Radu on Jun 5, 2015

    Hi all,

    I just build this adaptor for a 40D and I found out it wont work well in liveview. If you put the voltage regulator inside the battery dummy there isn’t enough heat dissipation and it will go in protection and shutoff.

  28. By Stefanvds on Jun 5, 2015

    Sad to hear that, but it is somewhat to be expected. Live-view does drain the battery quite a lot.

    Mounting the regulator outside of the battery would be possible, but it might get quite messy.
    What input voltage are you using? the higher the input voltage, the more heat needs to be dissipated.
    with my 400D and 12V input It never even became warm.

  29. By Radu on Jun 5, 2015

    well mine gets pretty hot with a 12V supply. Mind you, that’s over a few hours on live view.

    I put the regulator outside the battery compartment on a heatsink. It’s all good now.

Post a Comment

Motigo Webstats