What battery and what LED will work best to maintain constant brightness for 10 hours?

[danielgc]

Hi there,
Just to say I apologise for my lack of basic knowledge, this is something I am interested in learning more on!
Anyway I am looking to build a UV emitting light system that shines continuously for 10 hours at least, compromising of an LED, a battery and a resistor I guess. The goal is to light up a lamp shade about the size of a 2L coke bottle.
What battery/LED/ switch/ resistor should I be using for maximum effectiveness and efficiency?
Thank you very much,
Dan.

 

[DefyG]

Depends very much upon the output (lm,w) of the LED!

 

[Jim_e_Jib]

Depends very much upon the output (lm,w) of the LED!

That will be determined by what the OP is growing

 

[danielgc]

Depends very much upon the output (lm,w) of the LED!

Not quite sure how to figure that out, the LED’s I’m looking at are 4W if that helps..
Thanks!

 

[telectrix]

i'd be considering a 12V sealed lead acid battery, as used in alarm systems. measure the current with the LED and a battery set up on the bench, then workout the Ah required for 10 hours possibly a 3.0Ah would cope. a means of recharging wouls also be required.i use a 13.6V stabilised power suply, but any old intruder alarm panel would do.

 

[davesparks]

For a 4W LED you should consider a constant current driver circuit instead of using a resistor to control the current.

If you do use a resistor it is likely to need to dissipate more power than the LED rating so you could end up wasting much more of your battery's capacity as heat generated in the resistor than is actually put to useful work creating light.
[automerge]1594460639[/automerge]

measure the current with the LED and a battery set up on the bench,

Connecting a 4W LED directly across a battery will burn it out very quickly, it needs a current limiting circuit, for which the LED manufacturers data is required to find out what current is required.