Power supply for single cree led

Thread Starter

hzuiel

Joined Aug 15, 2017
7
I need to power a single cree led. It says 1000mA, but only 2.5v. I don't have any wall plug ac to dc adapters that put out 2.5V or even close really. I do have one that is 1000mA but 12V. If I used this, would it over-volt the LED and burn it up? What else could i use if this will not work?


SOLDERLESS CREE XP-E HE PHOTO RED (660NM) LED
SKU :

XPEEPR-L1-0000-00C01-SL
Forward Voltage (@1000mA) :


2.5V
Maximum Current :
1000mA
 

sghioto

Joined Dec 31, 2017
2,059
Yes it will unless you add a resistor in series but at 12 volts there's a lot of power wasted. At 1000ma you would need a 9.5 ohm resistor rated at least 25 watts. Some of those USB wall outlet supplies will deliver 5 volts at 2 amps, then you would only need a 2.5 ohm resistor rated a 7.5 watts. Next question is do you need to operate the LED at max current. Other options are using voltage and/or current regulators using discrete components or off the shelf items out there.
SG
 
Last edited:

Thread Starter

hzuiel

Joined Aug 15, 2017
7
Yes it will unless you add a resistor in series but at 12 volts there's a lot of power wasted. At 1000ma you would need a 9.5 ohm resistor rated at least 25 watts. Some of those USB wall outlet supplies will deliver 5 volts at 2 amps, then you would only need a 2.5 ohm resistor rated a 7.5 watts. Next question is do you need to operate the LED at max current. Other options are using voltage and/or current regulators using discrete components or off the shelf items out there
SG
I need to get as much light as possible out of this LED since it will be the only LED i can fit. This is for an aquarium, in a little plastic box growing algae, not in the main aquarium, so space is limited. In the past i just used meanwell constant current drivers that were sold specifically for LED drivers but typically they are for strings of 4-12 or more LEDs and are overkill and more expensive than what i would expect to spend.
 

sghioto

Joined Dec 31, 2017
2,059
Is this LED going to be on constantly?
EDIT: 9.5 ohm 30 watt chassis mount resistor from Mouser.
Or one of these DC step down converters from Amazon.
SG
 
Last edited:

Avid0g

Joined Apr 1, 2018
21
If you go with one of these little switching regulator cards, select one with a current limit control, not just the voltage control. The current control is what is important to the LED. You can set it and forget it. No need for resistors if the LED voltage is OK for the regulator design.

You need a volt/ammeter to set things up. If the voltage is set lower than the LED, you won't get light. If the initial current is set too high, the lamp may burn out before you can unplug, so adjust everything before installing the LED in the circuit.

First, set the output voltage higher than the required voltage. (You may need some load. Maybe.)

Use a 10 Amp meter configuration to short the supply Output. Adjust the current to a safe margin of error. Install the LED.

The biggest factor that kills LEDs is junction temperature, so you need to guard against that with a heat sink and temperature controlled fan. It only has to turn on high for the hottest nights.

Good luck!
 

Thread Starter

hzuiel

Joined Aug 15, 2017
7
If you go with one of these little switching regulator cards, select one with a current limit control, not just the voltage control. The current control is what is important to the LED. You can set it and forget it. No need for resistors if the LED voltage is OK for the regulator design.

You need a volt/ammeter to set things up. If the voltage is set lower than the LED, you won't get light. If the initial current is set too high, the lamp may burn out before you can unplug, so adjust everything before installing the LED in the circuit.

First, set the output voltage higher than the required voltage. (You may need some load. Maybe.)

Use a 10 Amp meter configuration to short the supply Output. Adjust the current to a safe margin of error. Install the LED.

The biggest factor that kills LEDs is junction temperature, so you need to guard against that with a heat sink and temperature controlled fan. It only has to turn on high for the hottest nights.

Good luck!
I have an autoranging ryobi multimeter from when i was doing contracting work that included security alarms.

The led will have 2 inch heatsink, this one to be specific. https://www.rapidled.com/large-single-led-heatsink/
Possibly with a little fan, not sure yet.

So another dc-dc converter, just one that has amperage control?
 
Top