A good driver for 4 IR LEDS in a 2 X 18650 host.

Flashlight Modding and DIY Parts
1

Guys, what would be a good driver for 4 IR LEDS like these:

http://www.lightobject.com/3Watt-850nm-Infrared-IR-LED-P58.aspx

in a 2 X 18650 host? The maximum driver diameter is 26mm.

Thanks.

2

Second try with this, anyone know of a suitable driver?

3

The Emitters have a very low Vf from 1.2 to 1.5 Volts. I suggest a serial wiring of the four LEDs and looking for a Buck driver with an input voltage range from at least 5.6 to 8.4 Volts and a maximum output current of 1 Ampere.

4

Thanks for the reply. Does the driver output voltage matter? Or are amps the only thing I need to worry about?

1.5vX4=6v Can the driver output be higher than that? I ask because the emitter specs say 3W - X4 gives us 12W or 12V @ 1A.

Pardon the novice questions.

5

yes, the voltage matters. too high and *poof* emitter is dead, instantly. too low = no light.

6

I beg to clarify dthrckts post.

If the battery voltage is too high, the driver will make *poof*, if it is too low, it will be too dim.

Your driver should have a minimum voltage of 5.6 or 6V and a maximum voltage of at least 8.4V. If the minimum voltage is higher, You will loose the regulation rather fast.

7

Try DealExtreme sku 3256, should meet your needs fine.

If you are buying a constant current circuit, or led driver and they list the output current and voltage, the output current is your concern. The voltage will adjust itself to keep constant current. But, if the driver specs show a range of voltages, your voltage need must fall in that range or below.

For instance look at the specs for this driver, http://www.ledsupply.com/l03u-350.php

This driver will output 350mA but only between 4 and 12VDC. So it would work fine for anywhere from 3 to 8 of the leds you ask about, but more or less would be outside of the specs.