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Solenoid Problem

  1. Jul 6, 2015 #1
    Hey All,
    I'm trying to design a solenoid that would generate about minimum 1.6 A of current in order for me to charge up a 1.5 A 1.5 V battery. I already designed one which is about 10CM in lenght and unknown number of turns (as I used a drill to wind the coils around it. so I would guess its about 2-3 thousands turns).
    I'm getting about 50 V PK-PK AC . However, I was hoping to make my solenoid smaller and more efficient. I did not perform any theoretical calculation on my first trial (mainly experimental)

    I was hoping if someone could guide me in the right direction on how I could be able to achieve this much of current.
    Is there a way to know how many turns/lengths I need based on only the current that I would like to have? B=Mni/l
    If so, then how would I be able to guess the magnetic flux in the above equation?

    Thank you all for taking the time reading my post.

    Looking forward to your suggestions.

    Last edited: Jul 6, 2015
  2. jcsd
  3. Jul 6, 2015 #2


    Staff: Mentor

    I can't make sense of your description. Perhaps you could better state what you are trying to do, and also draw a picture.
  4. Jul 6, 2015 #3
    I need to design a solenoid which I could get about 1.5 A of current. I need to determine the number of turns and lengths of the solenoid. I hope That describes it better,
  5. Jul 6, 2015 #4
    Are you trying to make a home made transformer + rectifier, so that you can charge a rechargeable battery from the mains electricity supply?
  6. Jul 6, 2015 #5
    Im trying to charge a double A battery using a solenoid and magnet.
  7. Jul 6, 2015 #6
    OK, got it now.
    You are making a home made dynamo of sorts.
    Your magnet is presumably arranged so that it's constantly moving in relation to the coil. (or the other way around).
    Usually this is done by having one element or the other spinning.
    One consideration is that the faster the spin the more higher frequency will be the ac output from the device.
    You will need a rectifier component of course to convert your generated AC to DC so that the battery is charged.
    I think but am not 100% certain, that the higher frequency AC (faster spinning) of the generator should result in a higher DC power output from the rectifier.
    I'll leave the precise math to somebody else.
  8. Jul 6, 2015 #7
    Thank you for your reply. The power is generated as the magnets moved horizontally in the solenoid as the person shakes the solenoid. This produces the AC voltage and then gets rectified to DC . My question was that how would I be able to exactly know how much turns or lengths do i require to produce 1.5 A of current.
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