Cheap and Easy PSU for Canon EOS

I think lot of guys here on Instructables know how much satisfaction is obtained building a gadget entirely by ourselves, but... sometimes it could be a clever solution opting for some nice and ready accessory. I think this is one of these cases.
I recently had the need to have a power supply for my Canon DSLR, an EOS 40D, to make some timelapse. For this pourpose I've bought an LM2596S step-down adjustable power supply module from eBay, it's very cheap, efficient, compact, and (I hope) safe... and it fits exactly inside my exhausted lithium battery case. And this instructable could be handy adapted for almost any digital camera battery, the only requirement is that the case contains the power supply module.

Step 1: Intro

The new psu is intended to work with a wall-plug transformer the same as with any DC power source between 9 and 35V, as a car battery or almost any wall-plug psu. This could be very handy in case of timelapses, gigapan shots, or long movies.

Step 2: What's Inside?

I've made the same modifications on two batteries, because both of them were exhausted. They weren't Canon batteries, indeed the original ones are almost ethernal.
You have to cut/crack the plastic casing all around the perimeter, because it's glued verty sturdy. Inside you'll find two 18490 Li-ion batteries, which are very rare to find to replace.

Step 3: Keep the Shells

Separate the battery parts unsoldering the battery contacts, and clead the case edges with a cutter, they should fit each other so we'll glue them at the end.
Maybe you wish to keep the protection circuit as replacement...

Step 4: Drill the Hole

Now take misures of the aperture which you find on your Canon. It's a little rubber door which you can bend to let the wire pass through. I've found that in battery-grip the aperture is in a different position, but if you're powering the camera by an external powersource probably you don't need the battery-grip. So I've opted for the in-camera wire position.
Drill an hole in that position and file it or cut it untill it becomes of the same shape of the wire. I've also added some heat-shrinking tubes to toughen up the cable extremity.

Step 5: Glue the Circuit

Check that the circuit fits in the battery case, I've had to file a corner to make place for the cable.
I've insulated the two unused contacts, and also added a piece of tape to not let the pcb touch them.
Then I've used a double-tape to lock the circuit in place. I've added another layer of tape over the one you see in the pictures.
You can then begin to solder the wires on input and output terminals.

Step 6: Solder It

You can see the glued pcb in place. You can now connect a power source to the cable ends, maybe 12 or 24 volts work good. With a multimeter misure the output voltage and turn the potentiometer until you'll obtain an (almost) exact voltage of 7.4V. 

Step 7: Label It

Now you can add the DC input range on a label behind the battery, together with output voltage and plug's polarity scheme. I've printed some coloured labels so you can cut them and glue into the shape of the previous one.

Step 8: The Socket

As female socket you could buy one of those nice ones which already have a cable connected. I've used a different type, and I had to solder the wires on them. Then I've enclosed them into some heat-shrinking tubes to obtain a better look.
[UPDATE] You can now see the detail of the cable coming out from the rubber cover near the battery door.

Step 9: Done!

Check another time that everything works good, let the power connected for a few time, try different input voltage, bend the cable, flex it, pull it, also chew it if you dare... it's better to get a shock now than to find your three months timelapse failed because of a bad soldering! Obviously I'm fooling with you, always pay attention to high current sources as car batteries, they're very dangerous!
Everything is ready, it's time to glue the shells pair, maybe with two elements glue, and try your new power adapter!

Comments

[Oki_]

I did something similar, only with step-up converter. But as a result, my camera does not even turn on. I checked voltage an polarity, everything is correct. I tried step-up converter itself and I was successfully drawing 1.5 A @8V. I absolutely do not understand, what is the problem. Only I can imagine is some time-domain related issue, that current demand is faster than this converter can provide. Do you have some idea?

I tested dummy battery with 5V to 8V converter from china and it works nice, except of taking pictures. My camera (Canon 7D mark II) is probably too power hungry for powering from powerbank, or there is insufficient current limitation in the 5V to 8V converter. That is why i tried DIY version with "larger" DC-DC converter.

[andrea biffi]

I think 1.5A is too low... my circuit should provide 3A max, and camera batteries, which in my case were two 18650, are usually very powerful. Li-ion cells can provide a huge amount of instant power, five times or much the amperage: 3V•3A•5=45W
Camera should not drink so much, but maybe more than 5W at starting...

[Oki_]

Thank you for reply, I was not expecting it :) That 1.5 A @ 8V was just a test of functionality, I connected a DC motor to output. A boost converter I intended to use (linked below) should handle 3A peaks at 8V without any problem. I also measured current flowing when turning my camera on (only with multimeter). It rises to max. 0.7 A @ 8V, so I really do not have a clue what is wrong.

Anyway, as a workaround, I plan to buy 8000 mAh 2S Li-po battery, but I am a little bit afraid of a full charged voltage. It should be up to 8.4 V. Fully charged LP-E6N has 8.15 V (measured). I expect camera will handle 8.4 V without any problems as ii certainly has some sort of converter (step down probbably), but what is your opinion? I want to evade of using any converters this time, as I do not have the best experience with it...

https://www.banggood.com/5Pcs-4A-XL6009E1-Adjustable-DC-DC-Step-Up-Boost-Converter-Power-Supply-Module-p-1178470.html?rmmds=myorder&cur_warehouse=CN

[andrea biffi]

I always reply to enthusiast makers!
I would say there will be no problem using 8.4V, just do it! 😬

[Ennowulff]

That was easy - you only had two pins... :D

I wonder how I can do the same with a Li-ion battery pack like LP-E5 for canon 1000D.

There are:
- two cells
- three pins
- bottom of the two cells leads to the board pin named "BC"
- top of 1st cell goes to "B+"
- top of 2nd cell goes to "B-"

where can I solder my wires from the step-down module to?

I think that I have to put minus-step-down to minus-board-pin and same with plus. But what do I do with that BC wire?

thanks for any hint!
enno

[andrea biffi]

Awesome! Thanks for your contribution!

[andrea biffi]

Ouch i have no idea... I hope members will help you with this. It will be useful!

[Ennowulff]

thanks for your fast reply!
I have a solution now. B- and B+ are minus and plus.
the BC pin is for something I hopefully don't need... ;)

[lupo.geminorum]

Andrea thanks, perfect job. My experiences with this buid are as follows:
- 7.4V is the nominal voltage of the LiOn batt. A fully charged battery has 8.4V. I decided to use this value;
- I have build an LM317 stabilizer that fits in the case and used a 1.5A power adapter (firstly I used a 400mA power source and that was to less - camera power cycle when shooting).

[ju1234]

Hello all,

I know it is an old link but in case some one can help, please respond.

I did not see this link before I made my device. But here is the problem I am running into. Advise:

For my EOS 40D, The original battery is rated at 7.4 volt. The body of the camera at bottom says 8.1 volt. The original dummy battery and ac converter that is sold by Canon for this camera is 8.1v 2Amp. So I am assuming a 2Amp 8.1 volt power supply should be adequate to run this camera. OK, so I made my dummy battery. Inserted it in the camera. Checked it out with multimeter that the connections are correct. Then I have powered it with many different sources with the same result.

I used a step down converter which is rated at 3amp to reduce voltage down to up to 8.4v (I am afraid i might burn the camera if I go over that) and used power from DC 12volt 7amp lead battery or 19v laptop battery or AC converter, they all give me same result. The camera sees the battery displaying an empty battery flashing sign in display but will not power the camera up. I even used an 18650 power pack (8.4v 8amp) directly (no step down) to the dummy battery. Same result. AC wall converter with 8.4v 2amp DC output directly, same result.

What am I doing wrong? thanks for the help.

[andrea biffi]

It's strange... my only supposing is that your psu doesn't really give 3A, but less than that when there is a load.

[andrea biffi]

And less than 2A...

[ju1234]

Thank you for answering. Like I said the problem is same when I use direct output as well. I used 110v wall converter which is 8.4 volt DC 2.1 amp and is originally for Sony camera and works with it. Hooking up that directly to the dummy battery without any voltage converter does same thing. I took out some 18650 batteries from a spare laptop battery. I have 2s 2banks (2 parallel X 2 series = 8.4v and I am sure it is more than 4Amp because the laptop charger is rated at 3.5amp). I connected those directly without any protection circuit or any thing else and still got same flashing empty battery icon. My multi-meter measures only up to 250ma so cannot actually test it.

[Sarasate]

I'd try putting 7.4V into the camera.

Just maybe the camera detects 8.4V as being to much more than the 8.1V.
Unlikely? But cheap to rule out.

[ju1234]

Sorry, forgot to mention, my dummy battery is empty shell, no voltage step-down or step up inside it like in this instructable. The step down I used was outside. I can measure the correct voltage at the dummy battery terminals when outside the camera.

[Mohammed AliA1]

Hi there,thanks .i've done it but please help me I had problem err99 please shooting is not possible. Please turn off the camera or remove the battery" ? ?

[andrea biffi]

check output voltage, it's probably wrong...

[TimotiusR]

i know this instructables is kinda old but im curious if i can use dc-dc step up instead of a step down module. i want to connect it to a powerbank with 5v output.

the modules looks like this:

[andrea biffi]

yes you probably can, if it supplies enough current :-)

[TimotiusR]

how much current does it need? btw thanks for the reply