This is the 12V DC 1.4watt fan I want to wire up to plug into the wall. https://sun-mar.com/product/12-volt-fan/

What specification (volts,amps, watts) are required in the power supply adapter that I buy?

This was done in the cabin I have bought, but since the fan is broken and was connected to an old Casio phone power supply adapter like the following, I want to make sure I get the proper product.

Old power supply adapter Old power supply adapter

  • 1
    Curious, Why THAT fan? There are so many fans available to easily plug into a wall socket...Or even a USB port.
    – RMDman
    Commented May 20 at 21:26
  • 2
    Its a replacement for the same compost toilet fan that was installed into this compost toilet many years ago, and is design to fit over a 4" PVC for toilet exhaust. I thought I would keep the post simple by just showing what fan I wanted to install
    – Quincy
    Commented May 21 at 0:25

2 Answers 2


If it's honestly rated at 1.4W, 12VDC, then any 12VDC supply equal to or greater than 117mA current rating will do.

The device won't draw more than it requires for current, so a 12V 500mA (6W) or 12V 1A (12W) or 12V 5A (60W) supply would all run it just fine. Or be able to run more than one of them.

Depending on how honest the rating actually is, they might also last longer than the original supply if the rating was not quite true and the power supply was overworked (which it should not have been at 59% load.) Then again, it looks rather old indeed, and even good ones don't last forever.

  • If the cabin is off-grid, a solar panel, 12V battery, and 12V charge controller might make a lot more sense than a 120V/12VDC adapter. Or a 24-12V or 48-12V DC-DC converter if there are already batteries in use at one of the higher voltages.
    – Ecnerwal
    Commented May 22 at 19:49

The old adapter lists 12V, 200mA so I would find one that matches that. A search on Amazon should get you what you need. (Wattage isn't typically listed, but if the fan draws the full amperage, it would be 12V*200mA = 2.4W).

  • The old adapter is not designed to work with that compost toilet fan, but an old Casio phone. It's a Jerry rig setup. And the adapter might be broken. So I am looking for the best possible new power supply to "do it right."
    – Quincy
    Commented May 21 at 0:27
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    @Quincy I would avoid buying on Amazon if you don't know what you're doing and want top quality. Too much unsafe non NRTL (UL/ETL) listed junk from China. Look at a electronics distributor like DigiKey or Mouser.
    – user71659
    Commented May 21 at 16:59
  • 1
    @user71659 Good point. Agreed with that one 🙂 Commented May 22 at 0:53

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