I have a Canon SX210 IS, which doesn't have the possibility to plug-in a external power source.

Because of that, I want to make a connection to the pins where the battery usually is. I'm a little confused about the voltage requirement because the battery says 3.7V and the base of the camera says 4.2V.

Since I have a car battery and a 7805 voltage regulator I thought I could power the camera directly with the 5V the regulator would give me. But I don't know if it's safe to do that.

You may ask why would I want to power the camera with 5V instead of using 4.3 from a DC regulator. Well, I'm outside the city right now so there is no way to get a DC power supply like that.

(don't ask where I took the 7805 from).

I've found out that my helicopter charger has a voltage of 4.2V and a maximum current of 850 mA, but it's a typical switched power supply (like the cell phone ones). Is it dangerous to feed my camera with that? What about a little paralell capacitor to filter noises?

  • 2
    Stick a diode in series with the power supply; diodes have a voltage drop of about .6 or .7 volts.
    – Evan Krall
    Feb 1, 2011 at 7:41
  • Also the reason the camera says 4.3 when the battery says 3.7 is because the fresh-charged voltage of a 3.7v Li-ion battery is about 4.3 volts. You probably don't want to exceed 4.3 volts.
    – Evan Krall
    Feb 1, 2011 at 7:44
  • What about using the voltage regulator and a diode in serial connection to drop 0.7 V. Is that valid?
    – tomm89
    Feb 1, 2011 at 8:00
  • Sory for the last comment, I didn't read the first one.
    – tomm89
    Feb 1, 2011 at 23:01
  • A switched power supply probably won't damage the camera, but will produce a lot of electromagnetic noise, which can cause noise and banding in your images. A linear regulator won't generate much noise at all.
    – Evan Krall
    Feb 2, 2011 at 0:54

3 Answers 3


I looked up an SX210 manual online, and it says that there is an external power port. Look at page 156 of your user's manual; the online guide I found recommended the ACK-DC30 kit. You plug a coupler (which has the same form factor as a battery) into the battery bay, and plug the AC cord into a slot in the battery door. The ACK-DC30 is $50 on amazon; you can probably get an off-brand version for less, too.

  • In fact, there is no physical conector, just a hole in the battery lid. And I'm in Argentina, so there is no way to buy that kit in Amazon, they don't ship here!
    – tomm89
    Feb 1, 2011 at 23:03

I wouldn't recommend doing this. You have no idea whether the 4.3v marking on the camera is some engineer being conservative (in which case the camera can probably take something a bit higher... maybe), or that there's a component in there that's gonna fry as soon as anything over 4.3v hits it.

Seriously, don't take chances unless you don't really care if the camera gets fried. If you can't afford to lose it then it's way better to be right than to be fast before you connect anything up. The correct regulator is going to cost much less than buying a new camera 'cause you fried it...

  • You are right, I'm affraid to put 5V and damage the camera. And I can't afford another one. Check my EDIT
    – tomm89
    Feb 1, 2011 at 23:21

Found a solution: a $5 DC to DC Converter like this

a $5 DC to DC Converter

Also you need to cut off 2 cables and remove the isolation and attach them to the DC converter.

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