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I bought this solenoid from ebay and was wondering how to power it.

It says 12 volts as you can also see from the picture, but I tested it with putting a 9V battery straight to its terminals for a while, the solenoid and battery got hot after a while.

I measured it with a multimeter and it read 9.0 ohms. Putting the multimeter through it measured 0.53 amps. Both with 9V battery

If I had battery eliminator that gave 12V output, what other components would I need to make it not go hot? Do I need some resistors?

And is it possible to get its power usage to a minimum with it still opening using various components?

Can I add lots of resistors and the voltage remains 12?

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    \$\begingroup\$ You could contact the manufacturer (from china [sic]) and ask them how to drive their solenoid, and why is it getting hot, and whether or not that is a problem. \$\endgroup\$
    – Nick Alexeev
    Commented Mar 31, 2014 at 22:24
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    \$\begingroup\$ It being April 1 now, I can only say that if you don't live in China you will need very long wires. \$\endgroup\$
    – C. Towne Springer
    Commented Apr 1, 2014 at 8:09

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If the coil resistance is 9 ohms, it should draw 1.33 amps at 12 volts, and dissipate 16 watts - so it will get quite hot. That current is much more than a common 9 volt battery can supply - from the current you mention, the battery voltage will be about 4.8 volts when trying to drive the valve.

Despite the eBay ad's claim, I suspect it may actually be an AC solenoid. On one dealer's website, I see coil powers for that size valve stated as 3 - 6 watts.

Adding resistors in series with the coil won't help - it will just reduce the current, and the voltage across the coil.

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    \$\begingroup\$ If it is A DC solenoid it may not be rated for continuous duty- It might be intended to actuate something for a short time. Without the manufacturer's data it's hard to know. \$\endgroup\$
    – John D
    Commented Mar 31, 2014 at 22:41
  • \$\begingroup\$ Yup, goes to show. I think i will buy a solenoid from another supplier with more info etc. Thanks! \$\endgroup\$
    – user6529
    Commented Mar 31, 2014 at 22:44
  • \$\begingroup\$ @user6529 EE.SE golden rule: "No datasheet = No sale." \$\endgroup\$
    – Nick Alexeev
    Commented Mar 31, 2014 at 23:15
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    \$\begingroup\$ @user6529 and don't buy Chinese junk on eBay (or any electronic component really) \$\endgroup\$
    – Matt Young
    Commented Apr 1, 2014 at 1:55
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Some solenoids current limit when switched correctly. Probably not this one, but you wouldn't know, would you? 9V is rather less than 10.8V, the rated minimum voltage.

Looking at it, I would guess that the way to keep it cool when switched open, is to run something like water through the valve when it is switched open.

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  • \$\begingroup\$ But they are claim this valve it is suitable for Gas as well, or maybe can control hot water. Have you any data from manufacturer, or it is a guess? \$\endgroup\$
    – GR Tech
    Commented Apr 1, 2014 at 12:23

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