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Thread: 1.7W 445nm

  1. #1
    Join Date
    Jul 2016
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    Default 1.7W 445nm

    I recently purchased a 1700mw blue laser that says it runs between 6-9 volts, so 2 18650 battery's equate to 7.4 volts which would work but i was wondering what would happen if i used only 1 18650 battery that is 3.7 volts would my laser power up and run at a lower Milliwatt or will it ruin my laser module,

    Thank you

  2. #2
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    ... diodes are best driven/controlled with current - this "6-9 volts" should be the input voltage for a constant current regulator or driver electronic.

    The 1.7W-diodes itself needs voltages between around 4-6 Volts max., so 9Volts direct connected to the diode will blow it for over-current ...

    Viktor

  3. #3
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    Quote Originally Posted by JJmcclelland View Post
    ...... if i used only 1 18650 battery that is 3.7 volts would my laser power up and run at a lower Milliwatt or will it ruin my laser module,......
    Certainly either one or the other ...... Click image for larger version. 

Name:	seesaw.gif 
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ID:	50320 ....exact balance is unlikely ..........using just the internal resistance of the battery to limit the avalanche current of an expensive diode IS NOT A GOOD IDEA.!

    If you do decide to go ahead ,,,please post the results .. but bare in mind that this is a very expensive method of determining the threshold voltage of any laser diode.

    Cheers

  4. #4
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    Thank you for your response, but if I understand correctly your saying that using only 1 battery could potentially ruin my module?

  5. #5
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    no they are saying running without a proper driver will ruin it no matter what you do. The forward voltage on the blues is at least 5-6v. If you fail to control the current with a proper driver then it will work for about a minute and be very bright followed by darkness.

  6. #6
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    Jul 2016
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    I have a proper 1.8a X-Driver in the module and a three element lens

  7. #7
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    Quote Originally Posted by JJmcclelland View Post
    I have a proper 1.8a X-Driver in the module and a three element lens
    Thank god! Then you need to give the driver at least 6-9V to run a blue well. The Vf is usually 4-4.5V so you need to add in 2-3v additional drop for the driver. I've seen them run on 5v but not very well.

    If you don't supply the Vf the diode can't do more than glow like an led if that.

    Vf=forward voltage for diode. I assume people know that but not always.

    So to answer the actual question you asked. one battery on the driver will not be enough to light the laser. It will not hurt anything just wont work.

  8. #8
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    That's true for your dark blue, but one 3.7v battery with no current limiting is certainly enough to fry Reds instantly!
    Cheers

  9. #9
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    Not true. If you have a proper driver the only thing that will happen with a red running on the higher voltage is the driver will need more heat sinking.

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