DC Solenoid HELP....

[asantini66]

I'm a carpenter by trade so have some patience...lol
I have a push type 12vdc solenoid. it has a rating of 7.5w for intermittent duty, and 2.5w for continous duty. I would like to work it for about 1 sec at a time, every few minutes. I'm actually using the solenoid to push a small button remotely. I'm not sure how to go about figuring out the battery set up. I would like to keep battery pack small?
I didn't know if using a cap with a 12v battery of lower mhr rating would work?
Any info you can give me would be appreciated.

 

[Mike_2545]

Just use a relay...if you need to keep the button too; wire the relay in parallel with the button....much more reliable.

 

[Boncuk]

Hi asantini66,

assuming the solenoid should be supplied with 12VDC the current at 2.5W will be about 200mA.

I suggest to use a small SLA (lead lead acid) battery of about 2.5Ah which will give you reasonable usage time of your circuit before you have to charge the battery.

Before you wire the circuit make sure your button is depressed properly at 2.5W solenoid power.

The info you provided is a bit vague. What do you mean by "every few minutes"?

Boncuk

 

[asantini66]

I can't open the unit up. picture the push solenoid pushing a key on your keyboard. Your holding a momentary push button in your hand, (from across the room) and every few minutes you depress the button, solenoid energizes and depresses the keyboard button. Sounds ridicules I know..... Just looking to see if I can make a battery pack with 12v 50mhr batteries or not. Would like to put battery pack and push button in one case you can hold in your hand.

 

[SABorn]

Edited..................

 

[asantini66]

yes exactly ....

 

[Mike_2545]

In that case, I might go with a button in hand and a car battery on the floor.

 

[asantini66]

will get many favors from wife if I can pull this off....LOL

 

[asantini66]

LOL.... thats what it seems like.

 

[asantini66]

prob not feesable.

 

[crutschow]

If you are only energizing the solenoid for a about one second "every few minutes" then ten AA NiMH rechargeable batteries in series may be sufficient (available in 12V packs for such things as model car power). They typically have a capacity of at least 2000mAH, which would give 10 continuous hours of operation or 36000 1-sec pushes at a 200ma (2.5W) draw. Of course that will be reduced if it requires more than 200mA to push the button.

You will get perhaps 20% longer life if you use alkaline non-rechargeable batteries.

 

[Sceadwian]

As Boncuk stated, you'd need a 2.5Ah battery, 50mAh isn't gonna cut it. If this is going to be connected by wires already why are you using a battery?

 

[asantini66]

maybe this will help... see attachment

 

[SABorn]

The basic fact is it will use 7.5 watts to energize the coil, then 2.5 watts to hold the coil energized, as all you are going to be doing is energize the coil and then release it, only the 7.5 watts if of interest here.

7.5 / 12 = 0.625 amps.

Due to the fact this will operated for less than a second on average, to would add upto not a lot of amp hours, but compact size for 12 volts is the problem.

It is likely that it will work off of 9 volts but the amps go up (7.5 / 9 = 0.833 amps) and you might get 100 button presses from a battery.

You really need to find a solenoid the is rated for a lower voltage, also remember that most solenoids are made to pull in and not to push out as you require.

Pete.