How to power this LED

[The Artist]

https://www.aliexpress.com/item/Freeshipping-10pcs-3W-UV-Ultra-Violet-High-Power-LED-Bead-Emitter-395-400NM-with-20mm-Star/2050610694.html

Can I just connect this to a 3.7V 18650 type battery? Do I need anything else to power it?

[G]

I'm not sure regarding that specific one.
If you search for 'direct drive LED' you get a variety of responses to similar questions that should be able to get an idea of the answer for this specific LED.

[smegballs]

I'd find the datasheet for it and then use a LM317 in constant current mode to drive it safely. You'll need more than 3.7V from a lithium ion battery tho

You could do it just with a resistor, but remember the working voltage of a li-ion battery is 4.2V charged, and 2.9V discharges (below the diode forward voltage). If you set the resistor for max permissible current at 4.2V, you will get less current, therefore less output, as the voltage falls off. A proper constant current regulation circuit skirts this problem. If you be wantings I can draw you a simple circuit that should work with it for you?

[smegballs]

Whats that application? It would be pikey as fuck, but you could have a resistor for when the battery is fully charged, then as it dims off you throw a switch that shorts out the resistor and drives the led directly. It won't have any protection against the battery voltage recovering a bit and forcing more current through tho.

Remember unlike a resistor, current through a diode is non-linear with voltage. A increase in voltage across and led can cause large increases in current, all-too-easily blowing the led. Hence the proliferation of all the various means of driving them.

Even better idea....

Use of of these constant current LED driver boards that come in the chinese 188650 torches.

https://www.dx.com/p/2-7v-6v-3w-cree-circuit-board-for-flashlights-15mm-2-7mm-25518#.VMGKokesWgY

They are small, cheap and designed to run power LEDS from 18650 batteries! Pretty much exactly what you want no?

[Aff]

Buy a Buck Boost Converter from eBay for a few ponds.
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Current Bikes:Honda 929RR Fireblade, Honda CD200 Benly (Project), Stomp Z2 140
Electric Bike Project

[G]

Incidentally, this site has loads of LED drivers etc:
https://www.kaidomain.com/

[WD Forte]

UV eh?
I'd be interested to know what the application is as well
security scanner? micro grow light?
____________________
bikers smell of wee

[The Artist]

Industrial leak detection. Nothing too interesting.

I am going to do some reading of the above links over the weekend and see what is most likely to work.