Anyone use one of these LED dimmers?

[Stones]

http://i53.photobucket.com/albums/g47/prestieb/leddimmer.jpg

Just wondering if anyone has tried using one of these LED dimmers with a non-dimmable driver? They can be snagged for about $4 off fleabay so it would be much cheaper than having to use the meanwells with the built in PWM or 0-10V dimming input channels as non-dimmable drivers can be found for pretty cheap.

[mseepman]

I believe this thread uses them.

http://www.canreef.com/vbulletin/showthread.php?t=82206

[Stones]

Thanks for the reply. Looks like they used the dimmers in that thread to regulate the voltage coming out of the power supply inline between the power supply and the high wattage LEDs.

Was curious to see if anyone had used these dimmers or similar ones inline between a constant current driver and a series of LEDs or if they are not suitable for this application.

[reefme]

May I ask where you are buying this?

[mseepman]

My guess would be dealextreme.com

[Stones]

May I ask where you are buying this?

They can be snagged for about $4 off fleabay

[mike31154]

Thanks for the reply. Looks like they used the dimmers in that thread to regulate the voltage coming out of the power supply inline between the power supply and the high wattage LEDs.

Was curious to see if anyone had used these dimmers or similar ones inline between a constant current driver and a series of LEDs or if they are not suitable for this application.

I've been meaning to update my LED build thread since I've added a few components including a 4th of these dimmers. Yes I regulate voltage through use of the dimmers and do not employ a constant current device between the power supply & the 10 watt LEDs hooked up in parallel. Quite simply, by regulating the voltage via the dimmers, I am regulating the current. The two go hand in hand. I took a fair bit of flak over this on the RC 'minimalistic high power LED thread' from an electrical engineer who didn't have too many good things to say about how I've gone about things. The discussion pretty much ended for me when he called the Chinese 'yahoos'. Well, I have news for him, there are plenty of very intelligent engineers in China & most of the products we use today with respect to LED technology comes from there. In my career as a technician I worked with many engineers & none of them openly disrespected their peers by calling them yahoos & certainly refrained from making racist remarks.

Am I taking a risk by not using constant current drivers. Sure, but I'm mitigating that risk by running the LEDs at below their maximum specified forward voltage & trusting that the manufacturing process is sufficiently precise that my 10 watt LEDs will run at close to the same current at a given voltage setting. If one is going to burn out prematurely at a lower forward voltage, it would likely do the same even with a constant current driver at some point down the road before it's rated life.

In any case, my fixture has been up & running since the beginning of April with absolutely no issues despite not employing constant current drivers. By now the LEDs are surely 'burned in' & if any were going to cook, they would have by now. As mentionded, I keep the voltage well below the specified maximum for the 10 watt LEDs (9-12V depending on which colour). Haven't had the voltage above 7 volts and generally run the fixture at 6 volts during the high light period. Lower for dusk/dawn of course.

Been meaning to make some current measurements at different voltages to compare what each LED is drawing, but just haven't gotten around to it since it's been working so well. I do have a bunch of constant current driver boards that are designed for the the 10 watt LEDs and a while ago hooked up a spare with the dimmer, constant current driver & a 10 watt LED. Unfortunately I can't recall how the LED reacted with both the dimmer & constant current driver. When I get some spare time I'll revisit that scenario. Here's a photo of the constant current driver for the 10 watt LEDs. I have a bunch of them laying around. Might actually use them some day.

https://public.blu.livefilestore.com/y1pShEpUEq5PplB7NQjFXfGSGbF3zIYXhcwrWLTsuAdttxMpCz 1NA_3LDTO43oYM35Sm4mTYADM2iuI3b7ta83_4Q/P1050410E.JPG?psid=1

Bottom line with these dimmers is that they are a great product for an excellent price. I've opened one up & the soldering is clean & professional. There are a couple of transistors in there, I assume MOSFETS to regulate the voltage in conjunction with the potentiometer. The dimming is smooth and will take the LEDs all the way down to shutoff. It shouldn't matter whether you're using them to dim a single LED or a string, as long as you keep to the power rating of the dimmer itself, which is 8 amps. I actually ran one quite a while at just over that limit & it's fine. I'll try to get back to you on how they work with the constant current driver. First thought is that it won't be very efficient, since the constant current driver will try to keep the current constant while you're fiddling with the manual dimmer. I think constant current drivers work better with pwm or other type of controllers/LED drivers. Throwing one of these dimmers into that mix just complicates things.

I now have four of them. Three are DC12-24V input & 8 amp rating, one is DC12V input & 8 amp rating. I have the two 12VDC power supplies I use adjusted down to just under 10 volts and the dimmers still work fine. I'll take more photos & update my build thread with the added power supply, switches, voltmeters & 4th dimmer in the near future. I purchased the dimmers thru eBay. Don't recall the seller(s), I think I used several due to pricing. If you wish, shoot me pm & I'll dig thru PayPal purchase history to find the sellers.

[Stones]

I'll try to get back to you on how they work with the constant current driver. First thought is that it won't be very efficient, since the constant current driver will try to keep the current constant while you're fiddling with the manual dimmer. I think constant current drivers work better with pwm or other type of controllers/LED drivers. Throwing one of these dimmers into that mix just complicates things.

Thanks Mike, I appreciate the input as well as the amount of detail you put into your response. I had assumed running one of these inline between a constant current driver would likely not work due to the way you had them wired in your LED build. However, it seems products like stunner strips can use a similar inline dimmer but perhaps they are not running off of a constant current driver and just a power supply as you did with your build. Thanks again and yes, you are corrrect as there is an abundance of these on ebay for all around the same price from multiple sellers.

[mike31154]

If I remember correctly the dimmer's 'designed purpose' is for the flexible LED strings that run off a 12-24 volt DC supply. Typically this application would not use a constant current driver. The two components, dimmer/constant current driver will work against each other.

After reading the thread again, I probably went overboard on my response. All you needed was the info on whether the dimmer is compatible with a non-dimmable driver. My answer is somewhat buried & inconclusive since I can't recall how the 10watt LED reacted with both the dimmer & non-dimmable driver with 12VDC supply when I hooked it all up using a bread board.

[Stones]

After reading the thread again, I probably went overboard on my response. All you needed was the info on whether the dimmer is compatible with a non-dimmable driver. My answer is somewhat buried & inconclusive since I can't recall how the 10watt LED reacted with both the dimmer & non-dimmable driver with 12VDC supply when I hooked it all up using a bread board.


No worries man. You gave me the info I was looking for and confirmed my suspicions that these dimmers won't work for my given application.

[Seth81]

Just my two cents here...if you want to be able to dim your LED's the most effecient easiest way is to start off with a dimmable constant current driver. I am an electrical engineer (mostly control systems) and after doing tons of research I used the dimmable constant current drivers from Thomas research products.


And to confirm what others have said, there is no way you can use a voltage regulator to dim LED's being driven off of a constant current driver.

[StirCrazy]

Just my two cents here...if you want to be able to dim your LED's the most effecient easiest way is to start off with a dimmable constant current driver. I am an electrical engineer (mostly control systems) and after doing tons of research I used the dimmable constant current drivers from Thomas research products.



Ill throw my vote in with this one. I am not an electrical engineer but I have done enough electrical and electronic courses to know this is the way to go.

The TR drivers are a little more money, but theres a reason for that, they aren't susceptible to inrush current like the Maxwell's are, there dimmers are built in with a few different options, and the sizes you can get them in let you use only two drivers (even for large arrays)

Steve

[Stones]

Thanks for the replies fellas. I've done a small LED build for my freshwater nano using dimmable meanwell drivers and was just wondering if there was a cheaper alternative than going with the dimmable version of constant current drivers. I'll check out the Thomas Research drivers as my next project will be using quite a few more LEDs than the previous one and I'd need quite a few meanwells to get the job done.