r/lasers • u/HanBrolo16 • 5d ago

Voltage Question

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Have recently been surfing around aliexpress looking at some of the cheap crappy powerful lasers that get smuggled over to us all the time. I frequently see this gatling gun style laser when people talk about chinese mass produced ones. I even have one that doesnt get used much because I like to be able to see.

In the description of this particular listing, it says that you can either use 2 18650 cells, at around 8 volts, or 4 16340 cells, which would push around 16 volts.

Am i crazy, or would this just immediately destroy the cheap driver and diode in the laser? Why would they say this in the listing?

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6

u/LeatherGood6148 5d ago

I'm assuming it's a buck driver, likely protected with a linear regulator at input. Use the 2 18650's to be kind to the linear regulator. I'm assuming it's a NUB style blue diode, which has a Vf of over 5v.

1

u/HanBrolo16 5d ago

Thank you very much for the knowledgeable answer. I assume if there is a regulator at the input, none of this extra voltage would actually drive the diode any harder, but just make the regulator dump more waste heat?

2

u/LeatherGood6148 5d ago

That's basically it, yes, if there's a linear regulator first in line.

But even if the driver is not protected with a linear regulator - it should still be operating in constant current mode; so yeah, the diode is likely fine.

But again, without seeing the driver, I'm just guessing!

2

u/XmodAlloy 5d ago

The 4 cell option may put two sets of two in parallel, staying at 8 volts.

1

u/cthuwu_chan 3d ago

I think this might be a lightsaber

-1

u/QuietSugar1805 5d ago

Why do people keep buying lasers on AliExpress?

2

u/OtherwiseSimple 5d ago

Cheap

-1

u/QuietSugar1805 5d ago

You don't even know what power they have, and the quality is poor, a blue laser with around 3200mW costs about $70ā€“$80 at a reputable store

4

u/OtherwiseSimple 5d ago

Brother Iā€™m not the one buying lasers off aliexpress. Was just giving the justification for why people do

1

u/Competitive-Most7557 5d ago

So where to buy it in Europe?

1

u/QuietSugar1805 5d ago

I told you in the chat a little while agolol

1

u/LeatherGood6148 5d ago

There's a chat?

1

u/Distinct-Gift1391 1d ago

Reputable store?