How to modify 10w RGB LED Flood for 12v landscape install?

[Teddy]

I purchased several of these 10w RGB LED Floods from Amazon ( LINK ). I want to use them as 12v and not have to run household current all along my back yard. They came with a 3 prong household plug attached. I opened them up and removed the little board and 3 prong cord and what I am left with is a red/black thin set of wires ( I am guessing maybe 23 gauge) which I connected to some 18 gauge speaker wire. If I connect them to a 12vdc power supply they work perfectly HOWEVER...

 

I purchased a 100w waterproof LED Power Supply (constant voltage) to which I hooked up 2 runs of 12/2 landscape wiring to ( LINK ). Then I connected these 10w Floods to the landscape runs. 5 of them on one run, and 4 of them on the other. This is approx 90watts of fixtures on a 100w power supply which should be ok I think.

 

They all work perfectly for about an hour and then the power supply trips and is very hot. The fixtures are also pretty warm to the touch.

 

I am not sure what I am doing wrong?! Did I cut that board out and shouldn't have?

 

I will also try to attach photos of the items here too. (The photo will show the board i cut out of them).

 

Any help is appreciated.

 

 

[Dave H1]

You may want to look through this posting a while ago.  Also, open up the front cover and see if there are any resistors located in there.

 

 

http://forums.lightorama.com/index.php?/topic/26405-10w-rgb-flood-light-reverse-engineering/?hl=%2Breverse+%2Bengineering

[scubado]

^{I'm surprised you didn't burn out the red's yet.  I think the reds run at 6-7v.  The leds will get warm, they should be mounted on a heatsink.  You also need a bigger supply or more than 1.  Also, how you going to control color with only two wires?}

[Teddy]

I saw that other thread. But keep in mind I am not trying to control them via DMX. The remote it comes with still works. All I did was remove the 120v to 12v board (in the pics) and then hook it up directly to the 12v cable. The fixture is still in tact just without that little board inside it. It responds to the remote control the same as always but I'm trying to figure out why they are getting warm (the unaltered version hooked up to 110v doesn't get warm) and why the LED transformer is tripping after an hour.

[Teddy]

I opened up the front and took a photo of the board behind the reflector. Hope this helps.

 

I am connecting them to 12 gauge landscape cable driven by a 100w waterproof LED power supply. I will also attach a photo of how I have that set up too.

 

Again, I don't need to control the colors by dmx. I just want to be able to use them without them overheating and causing my transformer to shut off. (Maybe I have it all hooked up correctly and my transformer is defective? I dunno!)

 

 

 

 

[Santas Helper]

You may want to look through this posting a while ago.  Also, open up the front cover and see if there are any resistors located in there.

 

 

http://forums.lightorama.com/index.php?/topic/26405-10w-rgb-flood-light-reverse-engineering/?hl=%2Breverse+%2Bengineering

 

I think Dave hit it on this. You still have resistors somewhere, probably under the front reflector (under the front cover as mentioned). There is a type I found to have that configuration. There is three different configs that I have ran into.

 

Jim, that would explain why there is only two wires he is using AND why the red LED has not burned up (still must be a small board/resistors in there). Also, looking at the flood Teddy purchased, the LEDs are mounted on the light housing as a heatsink.

 

Teddy, your on the right track. Just one more step. Find those resistors. BUT keep those resistors. You need them so not to burn up your LEDs.

If your running all three colors full time, your LED floods will get warm. The LEDs AND resistors have to dissipate a lot of heat.

 

And as Jim mentioned, you need another power supply on top of what you have. The power supply you are using probably has a thermal protection circuit and your very close to the max on it's limits I'm assuming.

 

And Teddy I am curious. What color did you have when you had all the LEDs on for that period of time?

 

Keep us posted on what you find.

 

Tom

Edited September 15, 2013 by Santas Helper

[viennaxmas]

Usually the LED floods are driven by constant current drivers, not constant voltage. Constant current is a lot better for the LED's and there are small ones available. The little circuit board you removed is exactly that + the color control.

Just using resistors is usually overdriving the LED's unless you calculate them to the spec of the LED - and as mentioned before, different colors require different resistors.

Using the wrong resistors can also be part of your overheat problem - the resistor defines how much power the led uses. Have you measured the total current of all your lights?

I have also noticed that in the summer most transformers I have can only be used up to 75% of the load rating or I have to use fans to keep them cool...

[Teddy]

I replied earlier but my post had to be approved because I'm new here. You can see my responses above with more detail.

[Teddy]

I reduced the floods to 6 for a total of 72 watts on the 100w driver and they have been running for 4 hours so far without tripping. I think it was a load issue!!

I ordered a 150w unit and I will put 10 total on it for a load of 120 watts leaving 30 watts. That should work!

You think I missed anything though?

This is really a cool project and it looks amazing!

Cost:

Floods (10) on amazon @ $15 each

150w waterproof LED Driver from EBay @ $67

12g landscape wiring 150ft @ $75

18g speaker wire spool @ $8

12 landscape quick connectors @ $20

Total cost: $320

Teddy

[Santas Helper]

Teddy,

I see you found the other board/resistor.

Now that we know you are still using the controller then the rest of what you have should be okay.

BUT... I would suggest (if possible) to check the voltage running out of the supplied transformer that came with the flood (original set-up). If you have one that you haven't hacked into yet.

It might be a little under 12vdc (around 11vdc) on the output side. If this is the case, that would explain why only the red LED has a resistor and the G & B don't. If you supply 12+vdc (your own power supply), that may be why they are running a little warmer than the others. AND if this is the case, then it would be wise to add a 2ohm resistor to the green and blue LEDs. Reason being those two colors are rated at 9 to 11 vdc while the red is rated at 6 to 8 vdc. Keeping the LEDs more in tolerance will prolong the life of the LEDs and not get as warm.

With this in mind (using a higher voltage), then you might need to change the resistor of the red LED to keep it's voltage around 6 to 8 vdc. A 18ohm resistor works nicely with 12vdc to these resistors.

Again, it's only a suggestion. But either way, I would take some sample voltage checks on both the unhacked and hacked floods just to see what you have. It might save you grief in the long run.

Keep us informed.

Thanks,

 

Tom

[Santas Helper]

A small thing to point out. For your set-up Teddy, there is already an 18ohm resistor being used on the red LED so that would be correct.

Also, I forgot to mention, on the individual voltages I mentioned above, this pertains to this type of LEDs used in this type of flood light.

Edited September 16, 2013 by Santas Helper

[scubado]

Keep in mind these leds can get quite warm running white at full power.  They have to be mounted to some type of heat sink.  My suggestion for you, next time you need a power supply, get a non waterproof one and mount it inside and run the power through the wall.  You can get 3x times more power for about half the price on Amazon.  You can also then tweak the voltage down to 11v if needed.  A lot of the bigger leds now use 36v or something above 12v and resistors are needed.

 

You're probably the first person that is using the remote controller on this forum.  The rest of us use LOR DC controllers or DMX so we can program what we want the lights to do.  That's why all the questions about your wiring and resistors.

[tjflory]

I used the resistors as discussed, but also have my power supplies turned down closer to about 11 volts.

 

tj

[Santas Helper]

I used the resistors as discussed, but also have my power supplies turned down closer to about 11 volts.

 

tj

So tj,

How did they perform? Much warming beyond normal? Just getting another's experience.

Please share the hack job and end result.

 

Thanks,

Tom

[Teddy]

Tonight 2 units blue LEDs stopped working.

[Santas Helper]

Teddy,

 

What voltage was you running? Did you have resistors on them?

 

I was experimenting with mine last night adjusting voltages and went a little high. Blew out my blue LEDs in one flood.

I'm trying to see what voltages/resistors work best.

[tjflory]

...Also remember voltage drop from your cording... it may actually work in your favor!

 

tj

[scubado]

I usually use a 1 ohm 1w resistor for blue and green if running at 12v.