Buying the 12V 10W COB units in the UK.

[Tim036]

I want to build my own floodlight but must use 12V DC, And the square units are more suitable than the round cree ones.

I live in the UK, and so far I've only found the round ones on sale. Does anyone know a UK (or far east ) source for the square ones?

I'm trying to find a data sheet for these items, because I found some in the far east but no datasheet ! : ((

Any thoughts anyone ?

Many thanks,

Tim

 

[Julian Holtz]

Hi Tim,

you mean these?

http://www.wayjun.com/index.php?main_page=product_info&cPath=53_229&products_id=853

I use the 50W ones with great success.

 

[Tim036]

Hi Tim,

you mean these?

http://www.wayjun.com/index.php?main_page=product_info&cPath=53_229&products_id=853

I use the 50W ones with great success.

Which power supply do you use for the 10W also which one for the 50W ?

Many many thanks...

: )))

Tim

 

[Julian Holtz]

Hi Tim,

you need to check out the datasheet, and see what the voltage and current demands are. Voltage is fixed, but you can lower the current to have less thermal stress on the LED.

The 10W LED for example has a 3x3 grid of chips, if you look closely. This means 3 chips in series and 3 in parallel.

Each chip needing around 3V means the LED needs 3x3V=9V, so a 12V driver is ok.

As it is a 10W LED with 9 Chips, each chip has a max power of 10W/9 chips=~1W/Chip.

1W/3V=~330mA per chip. This is the current you need. As you have 3 chips in parallel, you need 330mA x 3=~1A.

So you need a power supply with 12V and around 1A like this:

http://www.wayjun.com/index.php?main_page=product_info&cPath=183&products_id=839

But I recommend driving these LEDs at a lower current, so this power supply will work as well:

http://www.wayjun.com/index.php?mai...ducts_id=624&zenid=tpjpl304ereugjv1qvqk7sfm77

So, if you want 10W true power, rather than taking a 10W LED, I recomment taking a 20W LED with lower current, like this combination:

http://www.wayjun.com/index.php?main_page=product_info&cPath=53_229&products_id=854

http://www.wayjun.com/index.php?main_page=product_info&cPath=183&products_id=820


I run each of my 50W LEDs at 20W only with the same philosophy.

Here's a thread about it:

http://www.candlepowerforums.com/vb...IS-desk-lamp-modding-with-2x-50W-Epistar-LEDs

 

[poolman966554]

I want to build my own floodlight but must use 12V DC

Does that mean you need to power the driver from 12vdc?? if so, you could search for "dc-dc led driver". then find something at 1amp rated over 10watts.
a quick search found this : http://www.newark.com/xp-power/ldu2...w/dp/34T4705?MER=PPSO_N_P_EverywhereElse_None

 

[Tim036]

Many thanks for the tips and info... Very very interesting !

: )))

Tim

 

[Julian Holtz]

but must use 12V DC

Ah shoot, missed that one...

But ebay to the rescue with a fitting combo:

http://www.ebay.de/itm/10W-High-Pow...87067?pt=AU_Lighting_Fans&hash=item1c369f325b

http://www.ebay.de/itm/2x-10W-High-...87626?pt=AU_Lighting_Fans&hash=item1c46fa378a

This one is a DC-DC converter which lets you adjust the current.

http://www.ebay.de/itm/New-LM2596-B..._Measurement_Equipment_ET&hash=item3ceca46557