I’m very new to wiring LED’s and wanted some guidance. I’m creating a speaker stand out of clear acrylic and the base of the stand will house 5x 10w LED chips which will light up the whole arm of the stand which is 1.60m tall, http://www.ebay.co.uk/itm/351033863892.
I’ve been reading a lot about wiring up LEDs but I’m still not able to fully understand how to go about this :S
they will need to be run by a normal 240v mains plug. Now I’ve also ordered one of these, http://www.ebay.co.uk/itm/111461045580, but from reading more and more, I don’t think that’s remotely what I need lol
The details on the LEDs you have bought are a bit ambiguous, for example
Power: 10W
Voltage: 9-12V
Forward Current:1050 mA
9-12V, that is quite a big difference, at what exact voltage the LED has a forward current of 1050mA? Since the rating is 10W we can assume the voltage is something like 9.5V. Still assumptions and a nice datasheet is another thing.
The power supply you got is outputting AC voltage, since it's for halogen bulbs. The LEDs you got are DC or AC? Most LEDs are DC but they can also be AC, the seller simply does not specify. You may want to seller to specify that.
Since the LED’s are rated up to 12V and the power supply you bought puts out 12v, the simplest thing would be to wire them up individually (in parallel, that is) and make sure they have adequate heat-sinks or some chunk of metal behind them. If you hadn’t already bought the LED’s and the power supply, there are higher quality choices for both of those, but what you got should work fine, too. Let us know how it works out!
thanks for your replies! I’ve just emailed them for more info so hopefully they reply.
Will that one power supply be enough to power all 5 led’s at a full 12v of power if wired in parallel? Also, will I also need some kind of voltage regulator? I’ve heard resistor which this type of LED power isn’t practical?
You have five 10W rated LED’s for a total load of 50W rated. The power supply is rated for 180W total. Putting your loads in series will add voltages together and keep the same amperage. Since your power supply is rated for 12V and the top end of the voltage spread for each LED is also 12V, that won’t work. Putting your loads in parallel will add the amps together and keep the same voltage. This will work just fine with your application. Just make all the positive connections together and all the negative connections together.
Actually, since the power supply is AC, you could recover the other side of the 60Hz pulse by wiring two of the LED’s in a reverse polarity from the others. It would be better if you had an even number of LED’s. But, you only have 5 LED’s, so you could still do it, but it won’t be exactly balanced. I doubt your eyes will notice the slight lack of balance, however. I would probably still do it just for the fact of not throwing away half my sine wave from the AC.
Okay, you are now at the limit of my knowledge, or rather, I should say, my memory, as I haven’t thought about this stuff recently. Is it possible for the reverse voltage of a diode to be lower than the forward voltage?
XM-Ls have -5V reverse voltage rating and they are rated as 3.3V LED
Other LEDs like MK-R which are rated 6V and 12V I see reverse voltage being -5V for both 6V and 12V. So I guess it depends.
excellent. so i have pretty much what i need!
so im guessing the leds will draw the power (wattage) they need, the power supply won’t simply supply 180w to the led and kill them pretty quickly. i sound so stupid but i don’t wanna mess this up!
Oh yes it will! LEDs are diodes, but not rectifiers. Their structure is different from normal diodes and rectifiers. Negative voltages can cause effects like metal migration which will destroy them. You have to read the LED datasheet (lotsa luck with that…) to see how they can handle negative voltages.
Having some doubts if the LEDs are 12V or 9V for the specified forward current of 1050mA. because 12V * 1.05A is 12.6W not 10W.
But anyway it does not matter now, 12V DC output with 60W power should be OK.
ok thanks. you say in a parallel circuit, the amperage goes up with each LED that’s added so do i need a transformer capable of handing out 5a or am i just talking rubbish? I can find 5a transformers but they’re huge boxes and don’t particularly want anything too big if i can help it!
Okay, well, wrong as I was about LED’s being rectifiers, there is one thing that’s still true - it’s cheaper to buy or make a rectifier than to buy a new power supply. If you’re interested in going that route, a bridge rectifier is going to be the best all-around thing to do. You can buy those on e-Bay for a little money.
