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Solenoid Help

toskoforce

May 19, 2017
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Hi, Im just a beginner at electronics, please dont be annoyed by my nonsense.

I got a Solenoid Valve 24V DC 1/4, its for a low cost portable device that tests pneumatic lines on the fly (my own idea) that only needs to open for a fraction of a second and quickly shut to minimize the loss of pressure.

The problem is that I thought I could make it work with 3X standard 9V Duracell batteries inline (27V), I was wrong.


-Maybe I am doing something wrong?
-Maybe I should replace it for the 12v solenoid model and try again?
-Maybe its only going to work with two (expensive) 12v powertool battery units?

solenoid-valve-24v-1.jpg

Duracell-9v-Battery-Coppertop.jpg
 

toskoforce

May 19, 2017
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What is the coil resistance?
M.

I will test it with a multimeter tomorrow and reply with the update here.

ATM I have no idea, it only says on its side Model 2w025-08 Max 10 bar, ED100% IP 00/65, its a 1/4 inch 2/2 valve used for air tanks etc (ignore the numbers on the picture above).
 

Bluejets

Oct 5, 2014
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Cannot see the wattage on the coil but I wouldn't mind betting it exceeds the current handling ability of those little smoke alarm batteries.
 

Audioguru

Sep 24, 2016
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A little 9V alkaline battery falls flat on its face when it has a current more than about 0.3A. Then its voltage will have dropped to 6V in one hour.
 

toskoforce

May 19, 2017
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A little 9V alkaline battery falls flat on its face when it has a current more than about 0.3A. Then its voltage will have dropped to 6V in one hour.

Thank you for quick reply, I was wondering just that, however, wouldnt 7x of these batteries put togheter be able to power it? Just for fractions of second, a few hundred times would be enough.
 

Minder

Apr 24, 2015
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In series higher voltage, the current goes up proportionately and each battery see the same current.
M.
 

Audioguru

Sep 24, 2016
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Seven (?) little 9V alkaline batteries in series produce 63V with no load. If the solenoid draws 2A of current at 24V then at 63V it will try to draw 5.25A that is almost 18 times higher than the little 9V batteries can drive.

You need two 12V motorcycle batteries in series to drive that 24V solenoid.
 

toskoforce

May 19, 2017
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I replaced the coil for a 12v 1,5amp type, and now 4x 9v battery were able to work it.

However, the question is how many times will it be able to pop the solenoid open and hold it for 0.5 seconds, any guesses?

*edit btw these batteries are the "Knup" rechargeable 450mah 9v model (i think it have maybe 0.3 amps each).
 
Last edited:

Audioguru

Sep 24, 2016
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Google and I know nothing about "Knup" batteries.
An Energizer ordinary little 9V Ni-MH rechargeable battery is rated at 175mAh when its current is only 35mA and its voltage drops to 6V. At 175mA its voltage drops to 6V in about 20 minutes. Your 450mAh batteries are much larger.
 

toskoforce

May 19, 2017
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Im sorry, they are china generic built, and im Not sure it has 450 mah, so please just consider an ordinary 9v battery, or even suggest some other small battery that i could try (like RC stuff).
bateria-recarregavel-9v-450mah-kp-bt9v-knup-blister-original-D_NQ_NP_718221-MLB20730755334_052016-F.jpg
 

Audioguru

Sep 24, 2016
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I think the cheap Chinese 9V battery is only 45mAh but the decimal point is so small it is hard to see.
It does not say its chemistry (if it is rechargeable then it might be old fashioned Ni-Cad) and it does not say it is 8.4V (seven 1.2 cells). It might be old fashioned Super Heavy Duty carbon zinc.

My RC Li-Po rechargeable batteries can continuously supply 70 times their mAh rating or 140 times in short bursts.
 

toskoforce

May 19, 2017
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I think the cheap Chinese 9V battery is only 45mAh but the decimal point is so small it is hard to see.
It does not say its chemistry (if it is rechargeable then it might be old fashioned Ni-Cad) and it does not say it is 8.4V (seven 1.2 cells). It might be old fashioned Super Heavy Duty carbon zinc.

My RC Li-Po rechargeable batteries can continuously supply 70 times their mAh rating or 140 times in short bursts.

Wow Ni-Cad are old stuff allready? I remember when it was the new stuff, anyway please point me into a more specific direction, model of the rechargeable battery that you are refering to power my solenoid, il see if its available here.
 

Audioguru

Sep 24, 2016
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Cadmium is a deadly metal so Ni-Cad batteries have been banned in many countries. China still makes them.
25 years ago I used Ni-Cad batteries in wireless tele-conference microphone transmitters. Many got the "memory" problem and most ended up shorted but zapping with a high current temporarily fixed them.
Ni-MH batteries replace Ni-Cad batteries now.

In North America, Energizer and Duracell are the largest Ni-MH battery companies. Ten Energizer AA size Ni-MH cells will make 24V at 2A for about 1 hour per charge. RC Li-PO batteries are dangerous and need special balanced charger.
 
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