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Problems with burnt out blue 2 Watt + laser

Jaxson Smit

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If that build design works I'm all set to go but I'd like one of you guys with more experience to confirm it
 



paul1598419

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IIRC, that'll only give you ~760 mA of current. Not even close to the 1800 mA that the M140s can be driven at. But, you wouldn't want to use an LM317 to drive anything at that high current. You should be able to use it as you described if the resistors are paralleled. Might get ~900 mW of power out using a short focal length aspheric lens.
 

Jaxson Smit

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IIRC, that'll only give you ~760 mA of current. Not even close to the 1800 mA that the M140s can be driven at. But, you wouldn't want to use an LM317 to drive anything at that high current. You should be able to use it as you described if the resistors are paralleled. Might get ~900 mW of power out using a short focal length aspheric lens.
Is there anyway to use multiple lm317's? I would really like to get it at Max power and what you're saying is that my battery amount is too small?
 

Jaxson Smit

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If there isn't what do you suggest I use in place of my batteries and lm317 (I already bought ohm resistors and lm317's and a 4X AA battery pack that's why I was wondering)
 

paul1598419

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You likely only need a +5 volt source as any amount of voltage higher than +5 volts will be turned into heat. That is the problem with using linear drivers. You need the forward voltage of your diode plus ~1.5 volts extra for headroom. If you use two Li-ion batteries you will be supplying 7.5 volts. Use a buck driver and you eliminate the need for keeping your supply as low as possible. It is well worth the $30.00 price as they fit into a space as small as the back half of the module and at 1800 mA won't get nearly as hot either. The efficiency is in the upper 95%.
 

Jaxson Smit

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You likely only need a +5 volt source as any amount of voltage higher than +5 volts will be turned into heat. That is the problem with using linear drivers. You need the forward voltage of your diode plus ~1.5 volts extra for headroom. If you use two Li-ion batteries you will be supplying 7.5 volts. Use a buck driver and you eliminate the need for keeping your supply as low as possible. It is well worth the $30.00 price as they fit into a space as small as the back half of the module and at 1800 mA won't get nearly as hot either. The efficiency is in the upper 95%.
The buck drivers I'm finding on eBay are only like $2 do you know why? Also my voltage would add up to 6 volts so wouldn't that suffice? Thanks for all the help though I really want to build this!
 

WizardG

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The buck drivers I'm finding on eBay are only like $2 do you know why? Also my voltage would add up to 6 volts so wouldn't that suffice? Thanks for all the help though I really want to build this!
Those $2 drivers on feebay are made for LEDs. They don't have good enough regulation or spike prevention for reliably running laser diodes. They also lack any sort of soft start capability, a feature that our diodes really appreciate.

As to the power supply issue, a pack of 4 AA cells will start out at 6V but under a load of an amp or more they will very quickly drop to 5V or less. With the '317 regulator you need a bit of extra voltage over and above the Vf of your laser or your regulator won't ...regulate. If portability is required use 18650 lithium batteries or a 5 cell pack of NiMH cells.
 

Lifetime17

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The buck drivers I'm finding on eBay are only like $2 do you know why? Also my voltage would add up to 6 volts so wouldn't that suffice? Thanks for all the help though I really want to build this!
Hi J,
Just go for the SXD driver set to 1.8A for a M140'455nm diode. spend a little more and you will have a build that will last. Those M140's are cheat enough . Going to cheat and most likely it will fail . I built many m140 builds with these drivers no failure.
These Chinese drivers are plain BS ..
Rich:)
 

paul1598419

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Many of the buck regulators on eBay are just voltage regulators and don't regulate the current. I bought many years ago to see if they could be easily repurposed.....but, no. Still have a dozen or more in my stock somewhere.
 

Jaxson Smit

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Many of the buck regulators on eBay are just voltage regulators and don't regulate the current. I bought many years ago to see if they could be easily repurposed.....but, no. Still have a dozen or more in my stock somewhere.
Alright do you have any specific recommended sxd drivers?
 

paul1598419

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Yes. Have you looked at DTR's site? Just get the SXD set to 1800 mA and he will even add wires if you ask him to. That is a time tested best driver for the M140 diodes. With a short FL aspheric lens you will get over 2 watts out. I have one doing better than 2.2 watts. You can buy these lenses on eBay for less than $8.00. You can also get the one that DTR sells, but for the money it isn't worth it, IMO. At least for that build. His G2 lenses are the best, but not necessary for everything.
 

Jaxson Smit

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Do you think a standard laser module wouldn't be able to take the heat from the m140?
 

paul1598419

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You'd likely be okay using a nickel plated brass module, but there is no dispute that the pure copper ones are better. I use DTR's modules exclusively for ALL of my builds.
 

paul1598419

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i really don't know. It has nothing to do with his name. I never asked to tell the truth.
 




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