Looking for some help wiring high-powered 12V LEDs with a 12V power supply

[LEDMagicSmoke]

As the title suggests - I'm trying to install some high powered LEDs for home accent lighting - the first time I tried this I wired the LED directly to the 12V supply, and the LEDs got so hot they melted the solder off .  I think what I'm missing here is a current-limiting resistor, but how do I go about selecting the right resistance?  

 

For reference, this is the LED I'm using:
https://www.digikey.com/en/products/detail/cree-led/CHA0410-0000-000D0U0A30G/17627895?so=92202305&content=productdetail_US&mkt_tok=MDI4LVNYSy01MDcAAAGZ-i1h91nJcfgXFG6-Jlp-Dq8_otqmq6m6JrhdRT2TCgj30RGlRO1WQsywGiimfmzQ_PBC_k5ULpDHXcUqhARqRU7jMHr4Zah1gAUFEulw5w

 

12V forward voltage, trying to shoot for 300-600mA driving current.  If I go by the usual resistor calculator for series LED, that gives me Vi-Vf = 12 - 12 = 0 so obviously not helpful in selecting a resistor.  Any help/insight would be appreciated.  Thanks!

[Average Nerd]

Are you using heatsinks? Normally, LEDs like these overheat rapidly if they are improperly cooled.

[LEDMagicSmoke]

No heatsinks - they were melting their solders within 10 seconds though - do they overheat that quickly without a heatsink?!

[Average Nerd]

7 minutes ago, LEDMagicSmoke said:

No heatsinks - they were melting their solders within 10 seconds though - do they overheat that quickly without a heatsink?!

If they aren't being current limited so they draw whatever they feel like, they can go from room temp to 200°C very quickly, yes

[Electronics Wizardy]

1 hour ago, LEDMagicSmoke said:

As the title suggests - I'm trying to install some high powered LEDs for home accent lighting - the first time I tried this I wired the LED directly to the 12V supply, and the LEDs got so hot they melted the solder off .  I think what I'm missing here is a current-limiting resistor, but how do I go about selecting the right resistance?  

 

For reference, this is the LED I'm using:
https://www.digikey.com/en/products/detail/cree-led/CHA0410-0000-000D0U0A30G/17627895?so=92202305&content=productdetail_US&mkt_tok=MDI4LVNYSy01MDcAAAGZ-i1h91nJcfgXFG6-Jlp-Dq8_otqmq6m6JrhdRT2TCgj30RGlRO1WQsywGiimfmzQ_PBC_k5ULpDHXcUqhARqRU7jMHr4Zah1gAUFEulw5w

 

12V forward voltage, trying to shoot for 300-600mA driving current.  If I go by the usual resistor calculator for series LED, that gives me Vi-Vf = 12 - 12 = 0 so obviously not helpful in selecting a resistor.  Any help/insight would be appreciated.  Thanks!

Normally you want a constant current power supply to run these, not a resistor for a high power LED. They should make a lot of these for driving leds.

[manikyath]

two things:

 

1: these arent "12 volt" LED's, they require a 12 volt 900mA constant current LED driver.

2: you defenately need a heatsink for a LED like this.

[Kilrah]

At least genuine Cree LEDs have a detailed datasheet so you can figure out the requirements. But yes as mentioned firstly it's not a 12V constant voltage supply but a proper 900mA constant current LED driver capable of about 14V min that you need, and a heatsink around 2K/W i.e something like the below per LED. 

 

 

You may be better off buying off the shelf 12V LED halogen replacements.

[RollyShed]

From the specifications it doesn't indicate a current limit supply is necessary. However they will get hot or VERY hot. First thing to do would be check the real current with a 12 volt supply to see what is actually happening. Do it quickly, or VERY quickly.

Current - Test 525mA
Temperature - Test 85°C
Voltage - Forward (Vf) (Typ) 12V

 

Full documentation is here -

https://downloads.cree-led.com/files/ds/x/XLamp-CHA0410.pdf

[Kilrah]

6 hours ago, RollyShed said:

From the specifications it doesn't indicate a current limit supply is necessary.

That's how leds work. You're kinda suppoed to know such basics.

[RollyShed]

6 hours ago, Kilrah said:

That's how leds work. You're kinda suppoed to know such basics.

What I am saying is the item is likely to have a current limiter built in. Yes, a bare LED needs a current limited supply but this is a complicated unit by the look of it and by the specifications given.

[Kilrah]

Nope, just a bare LED. Multi-chip but that doesn't matter, it's got the characteristics of a LED.