Best lens for NUBM4F @ 5000mA? Best 18650 batteries?

[jdzipf]

Currently using a 3 element AR coated glass lens. This picture was taken with the output against the wall 20 feet from the aperture. The dot is 1.5 inches long. Any suggestions on getting this tighter? Thx

Also, I have some "9900mAh" 18650 batteries but they are so light, i know for sure they are fake and I'm probably not getting very good performance out of them. What is the best battery to use on the above setup using 2 18650's. I've heard Panasonic, but this was years ago. Thx again!

 

[Z80 Lasers]

Adding a Beam Expander is a better option than changing the lens. You're not really going to get any better spot by just changing the primary lens.

 

[paul1598419]

6X cylindrical lenses are best to take care of that divergence. Also, any XXXfire batteries will always be way under spec.

 

[RawCuriosity1]

How much space do you have for optics? The best approach should be fast axis correction using a 6x cylindrical lens you can find from OPT lasers. You're going to have to do some tinkering with the lens setup to get the right axis corrected. Theres a good post from a few years back about correcting a NUBM44 with a cylindrical lens. A beam expander will also help with all divergence.

 

[GSS]

Currently using a 3 element AR coated glass lens. This picture was taken with the output against the wall 20 feet from the aperture. The dot is 1.5 inches long. Any suggestions on getting this tighter? Thx

Also, I have some "9900mAh" 18650 batteries but they are so light, i know for sure they are fake and I'm probably not getting very good performance out of them. What is the best battery to use on the above setup using 2 18650's. I've heard Panasonic, but this was years ago. Thx again!

View attachment 79426

Like Paul mentioned any *****fire batteries are way way over spec to the point of it being comical.

Even the best 18650 batteries will be around 2,200 to 3,000 mAh.

Efest's are decent, AW's, Panasonics and lately there are alot more choices for good cells.. When I joined here around 9 years ago there were maby 1/2 the choices..

 

[RedCowboy]

If you want a tighter burning spot at distance you can also use one of the FAC enhanced laser diodes along with a longer FL and subsequently wider lens, such as a zoom head flashlight arrangement, this will result in a wider starting beam width and a much tighter far field spot.

Thread '5W FAC laser diode ( line output )'

Apr 21, 2022

Just testing one of the fac enhanced 5W multi mode blues ( line output ) the spec sheet looks identical to 7A75 raw divergence before the added fac of course, the raw output with it's fac is a bar but much smaller than it would be without the fac.

I set up a random lens from my collection of scavenged optics and got a nice spot @ 15 feet about 2/3 of a pencil eraser, it could be a lot tighter with a bigger/longer FL lens, this would be good for lighting the old campfire, thinking about putting one in a threaded zoom to focus head FL.

This one is doing 6W @ only 3.5A...

• RedCowboy
• Replies: 27
• Forum: 445nm Lasers

• 

 

[RedCowboy]

As for 18650's any quality cell of IMR or INR formulation will be good for high discharge rate devices such as our lasers, look at the specs for mAh and discharge rate listed as sustained and peak current, you trade capacity for discharge rate so take into account if your driver is bucking or boosting. That said most quality IMR or INR cells will do just fine.

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[paul1598419]

LIION has been my favorite distributer for years.

 

[jdzipf]

Thanks for the great responses. I will post up any results as soon as I make the modifications.

 

[GSS]

Thanks for the great responses. I will post up any results as soon as I make the modifications.

You should also get a decent charger. The cheap ones that come with a complete laser kit usually don't shut down after full charge.
I'm not saying you have a cheap charger but just giving you a idea on how the cheap ones look.

You can get nice 2 bay charger for $20 or less that will stop charging when full.

I see you have been a member for 14 years
Have you bought decent safety glasses? Again the ones that come in a laser kit are usually the cheap ones.