Sherman Posted February 8, 2009 Share Posted February 8, 2009 Wow 1.4 A is the highest your LED can run.But if the heat is not dissipate well your LED life will be greatly reduce. Or am I over react?? Link to comment
Sherman Posted February 8, 2009 Share Posted February 8, 2009 PWM=Pulse Width Modulation. It's a square wave signal that has a fixed frequency (period), and you change the amount of on time and off time in that period. It's used for things like motor control and dimming to simulate using analog devices like a potentiometer for the same functions. This might explain things a little better. evilc66 do not really understand how the pwm function as a dimmer. From the illustration look like it only on or off at a set duration. Link to comment
evilc66 Posted February 8, 2009 Share Posted February 8, 2009 evilc66 do not really understand how the pwm function as a dimmer.From the illustration look like it only on or off at a set duration. Right. You chop the voltage at a high frequency, and the stutter from it being turned on and off turn into controlled brightness. You can only use it in devices that can be switched on and off very fast, like LEDs. For a driver like this, this signal does not directly drive the LEDs. It just an input signal into the chip that controls the brightness. Link to comment
npain316 Posted February 8, 2009 Share Posted February 8, 2009 I had a little time, so I hooked up the multimeter and as was stated above, the current was higher than specified. Full pot = ~1.6 amps, so I dialed it back to 1.4 amps for running two 12 led strings in parallel. This is a little higher than spec, but I thought I would try it. Also for note the minimum current when adjusting the Pot, was 300ma or so. If anyone uses this device, they will need to use a multimeter to dial in the proper current. At this point I am happy with the device. Did you ever go back to one string at 1A to see if the LEDs look bright? Evil, Any ideas on how we can get an external pot on this? Link to comment
zingtaw Posted February 8, 2009 Author Share Posted February 8, 2009 The 1.4 amps is across two strings, so ~700 ma per string, well within the LEDs specs. I have not had a chance to connect only one string yet. I was thinking about really studying the Driver/powersupplys PCB to see if by some chance the mod is obvious, just add the wires, or if other mods are needed. It might be worth ordering one that dims to see what the difference is. Both Analog and Digital. Link to comment
Sherman Posted February 8, 2009 Share Posted February 8, 2009 Right. You chop the voltage at a high frequency, and the stutter from it being turned on and off turn into controlled brightness. You can only use it in devices that can be switched on and off very fast, like LEDs. For a driver like this, this signal does not directly drive the LEDs. It just an input signal into the chip that controls the brightness. Ok now I get it.Thank You so much evilc66 Link to comment
Sherman Posted February 8, 2009 Share Posted February 8, 2009 The 1.4 amps is across two strings, so ~700 ma per string, well within the LEDs specs. I have not had a chance to connect only one string yet. I was thinking about really studying the Driver/powersupplys PCB to see if by some chance the mod is obvious, just add the wires, or if other mods are needed. It might be worth ordering one that dims to see what the difference is. Both Analog and Digital. I see. I thought you pump 1.4 amp into each rung Link to comment
evilc66 Posted February 9, 2009 Share Posted February 9, 2009 It might be worth ordering one that dims to see what the difference is. Both Analog and Digital. This was my thinking too. Could you tell me what the numbers are on top of the chip in the bottom right corner of the third picture you posted? Could you also get a better/bigger picture of the right side of the board? Link to comment
Ocean Flyer Posted February 10, 2009 Share Posted February 10, 2009 yahooooooo...I have finally ordered the 2 pcs of ELN-60-27-P (with PWM function) today from our local distributor, Singapore at the cost of USD35/pc . The price is indeed cheaper compare to US with PWM function . However...the lead time is abit long which is estimated around 4~6 weeks so I'm expecting the item to be delivered before this April . Link to comment
evilc66 Posted February 10, 2009 Share Posted February 10, 2009 Thats good to hear. At least we know the price from the factory is better than from Meanwell USA. I will have to bug Powergate today about this (they are horrible at getting back with me). Link to comment
Catfishboy747 Posted February 10, 2009 Share Posted February 10, 2009 Curious question Evil. On my 29g FW planted, I have 15 LEDs being driven @ roughly 700mA using a computer PSU (12v) and 5 of these http://www.instructables.com/id/EK2XAPS11GEWOF2YSD/ Whats to stop me from building the PWM controller and hooking it into the input before it gets to the DIY drivers. Am I missing something here? Link to comment
evilc66 Posted February 10, 2009 Share Posted February 10, 2009 You could. You would have to change the frequency to something much higher, say around 500Hz-2KHz. No chance of flickering there. The only thing with this is that you aren't really changing the current to the LED, just turning it on and off really fast (the Meanwell drivers will vary the current output based on the incoming signal). If the frequency is high enough, you will never see the difference, but the thermal characteristics will be similar to if you just ran the LED on all the time. Not saying it won't work, just a different way of doing it. Link to comment
Sherman Posted February 11, 2009 Share Posted February 11, 2009 yahooooooo...I have finally ordered the 2 pcs of ELN-60-27-P (with PWM function) today from our local distributor, Singapore at the cost of USD35/pc . The price is indeed cheaper compare to US with PWM function . However...the lead time is abit long which is estimated around 4~6 weeks so I'm expecting the item to be delivered before this April . Care to share where you order from. That is cheap compare to the quote I receive so far Link to comment
evilc66 Posted February 11, 2009 Share Posted February 11, 2009 So far, thats also a lot cheaper for small volume sales than I have been getting. Link to comment
moneyman6891 Posted February 11, 2009 Share Posted February 11, 2009 So if I order one of the standard drivers from meanwell, I just wont be able to dim my lights? I dont really care about dimming, I just want a cheap, relible driver. Link to comment
evilc66 Posted February 11, 2009 Share Posted February 11, 2009 Right. Cheap we know, but reliable is still in question. I have no doubt that it will be fine, but you never know. Depending on how things shape up, the standard drivers may be able to be modified to be dimmed. Time will tell. Link to comment
moneyman6891 Posted February 12, 2009 Share Posted February 12, 2009 going to order 3 so I can start my led adventure. would 3 be enough to power 30-36 leds or could I get away 2. I have a 24 gallon aquapod so I thought that would be enough light. Link to comment
evilc66 Posted February 12, 2009 Share Posted February 12, 2009 Technically you would only need two. The ELN-60-48 should do 13 LEDs comfortably. Link to comment
moneyman6891 Posted February 12, 2009 Share Posted February 12, 2009 ok thats good. I will keep researching to see what I need but at least I know which powersupply and leds to get. Link to comment
Sherman Posted February 12, 2009 Share Posted February 12, 2009 Technically you would only need two. The ELN-60-48 should do 13 LEDs comfortably. You mean at 24 volt ? Link to comment
evilc66 Posted February 12, 2009 Share Posted February 12, 2009 Either or. Depends on how you wire up the LEDs. The 48v will allow you to run them all in series. The 24v would have you run two strings of 6 in parallel. Link to comment
Catfishboy747 Posted February 12, 2009 Share Posted February 12, 2009 Hey Evil, the above link the PWM, that schematic is wrong, Or at least it was for me, had to use this one http://www.discovercircuits.com/PDF-FILES/SIMPLEPWM2.pdf, though I need like a 10K pot or something. Link to comment
evilc66 Posted February 12, 2009 Share Posted February 12, 2009 While I don't necessarily think it's wrong, it is another way to do it. I actually ended up building my version the same way as the one you linked to (I couldn't find the link to my original). I have built that one that I linked to earlier and it worked. The square wave output wasn't as tight though. Link to comment
Catfishboy747 Posted February 13, 2009 Share Posted February 13, 2009 It may be another way, but for some odd reason it didn't work for me. Link to comment
SkiFletch Posted February 13, 2009 Share Posted February 13, 2009 Now that schematic looks just like the motor controller I use at work all the time. Link to comment
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