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As title says, can 12V car wiper motor be powered using PC power supply? According to amperage of typical car wiper motor I would say yes, but I want to check :) Thanks in advance

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    \$\begingroup\$ What's the amperage of a typical wiper \$\endgroup\$
    – Passerby
    Commented Nov 27, 2015 at 3:26
  • \$\begingroup\$ About 5 Amperes ... \$\endgroup\$
    – hari
    Commented Nov 27, 2015 at 3:29

5 Answers 5

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Probably; assuming you use the 12 V line. Some PC power supplies don't start unless there is a load (20 mA ?) on the 5 V line.

You need to watch for the motor inrush (stalled) current, not the operating current.

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It should work. (Considering you checked the voltage&amperage on your car and power supply) Here is a link that has more details: http://www.scary-terry.com/wipmtr/wipmtr.htm and more about the power supply: http://www.scary-terry.com/atxps/atxps.htm Hope it helps.

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That should probably work.

  • All matter is correct voltage and the amperage. As usual a PC power supply of 250W wattage can output maximum current around 14A amperes. The maximum output ranges are marked on the power supply according to the voltage range.
  • It is safe for the power supply until the motors’ maximum input amperage is below than the maximum output of the power supply. You can switch ON the power supply by connecting the “Green” color wire in the mother board socket with any black color ground wire with a jumper cable. -Make sure to use only “4 pin Molex connectors” or “floppy connectors” to obtain the voltages. Don’t use any mother board sockets pins for that because they have not built for heavy amperage uses.
  • I also agree that use of a fly back diode for better safety of the power supply.
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You are probably better off using a somewhat older power supply. At IBM XT times, floppy drives tended to be run on the 12V power supply (at PC times, even the RAMs needed a 12V rail) so the 12V rail is quite capable.

Older power supplies lack any of the modern sensing interlock controls. That means that if you flip the power switch, the power supply will be on. Modern power supplies have a complicated startup procedure including a soft-button, presence detection, minimum load requirements on the 5V rail, et. al. So using an older power supply will make your life easier.

It might also be a good idea to check that your circuitry contains a fly-back diode to keep the motor from trying to feed back power into the circuitry or power supply when switching it off.

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  • \$\begingroup\$ As 5¼inch floppies got faded out, the 12V rail stopped seeing significantly more use than the -12V rail (which was basically just there for serial interfaces) False. Modern ATX supplies still see the majority of power drain on the 12V rail. A typical ATX supply will have half of it's rated wattage on the 12 rail(s) \$\endgroup\$
    – Passerby
    Commented Nov 27, 2015 at 9:35
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    \$\begingroup\$ @user -- Welcome to electronics.se! I've made an edit to your answer to address Passerby's (correct) concerns. In time, he may notice the edit and remove the down-vote. If you do not agree with my edit, you can click the "edit" button below your answer and restore the text to something you agree with. \$\endgroup\$ Commented Nov 27, 2015 at 9:46
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The stall current of a wiper motor is about 20A, so assuming you have a power supply that can satisfy that, or are using a soft-start circuit it should work.

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  • \$\begingroup\$ Weird how this and all other answers from years ago say it should work. Based on my own exprience and questons about ATX supplies used as power supplies for custom projects, mostly people ask why it does not work. I would not expect it to work, if the only load is the wiper motor and no other lod. \$\endgroup\$
    – Justme
    Commented Jun 19, 2023 at 4:57

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