Question about driving 3 tiny power supplies. Am I doing this right? - General

To preface this, I have barely any clue what I'm doing, and I don't really know the right questions to google to get this answer. I'm looking at powering a series of 12W LEDs using mains power, and I came across these power supplies that fit the bill perfectly (The 1A 12V option) https://www.ebay.com/itm/AC-110V-220V-TO-DC-5V-12V-24V-Switch-Power-Supply-Driver-Adapter-LED-Strip-Light/152134115704?hash=item236be66178%3Am%3AmnohYz4NZlT_Dq5l5lWNUMg&var=451331021400 So I'm wondering, if I were to set up 2 or even 3 of these, could I hook them all up to the same mains power like this? (click for bigger) http://puu.sh/Bx0bW.png Or would they all have to be connected to separate mains outputs? Thanks in advance. Ask me questions if my shit's confusing.

Yes. What you're doing is basically the way an extension cord works. Things I would look out for: Use standard 240v mains 2 wire cable, or 3 wire if the psu has ground, just to be on the safe side Use a standard DIY mains connector (every electronics store has those) Use electrical chocolates if you're not sure how to connect things Make sure the connection contacts are tight to prevent arcing Insulate wires where needed (especially if you don't do chocolates)

Thanks, that's very helpful. I'll be as careful as possible.

Actually, just do be clear, do you specifically need 3 power supplies for some reason? If a single power supply can provide enough power, one should be fine.

One provides 12v & 1A All of the LEDs individually require that amount of power Surely this means I'd need 1 for every LED, right?

You can just get a single 12V 3A power supply for the same effect (though I would probably get 12V 5A so it's not at peak load constantly). Afterwards, you can just connect them in parallel, exactly how you planned to connect power supplies to the mains.

So 5A doesn't mean that it'll blow up the LEDS? The LEDs only draw what they need, is that correct?

What you're thinking of is an unregulated power supply, which are more lab equipment or specialist applications these days. Most power supplies an average person ever interacts with are regulated power supplies.

Right. I'm just uneducated as shit when it comes to this stuff. Thanks for the explanations.

No, it means that 5A is the maximum the LEDs can draw before the fuse blows (if it has one). As Murk said above, this is true for any "regulated" power suppy such as this one (a voltage regulator on the unit keeps the voltage in check).

So I now discover that the 12V LEDs I bought instantly self-destruct when supplied with 12V of power. I measured the PSU output, I double checked the LED specs. What gives? Is it just the curse of eBay? Guess I'll have to throw away a few volts somehow. 9V seems to work fine.

What are the LEDs you are trying to use? You cant just run LEDs off a power supply unless you put a resistor in line or you use a driver board to limit the current.

UV LED eBay Your latter part seems to contradict the other posts in this thread, so I'm not sure I understand. Don't the LEDs draw only as much current as they need?

LEDS will pass as much power as they can get a hold of. They are called diodes for a reason, its basically a dead short in the circuit. A driver board will regulate the current going through the LED to keep it from burning up (you still need to put a heatsink on the LED) and give the most light. Look for a 10w 12v led driver on ebay they are pretty cheap.

Amps are pulled, not pushed. The load determines the amps, and the power supply limits the amount it can pull.

@Murk Suggested I bought this 60W one instead of the 12W ones I was originally going to buy. I didn't realise this meant my LEDs are now going to blow up unless I had some extra device not mentioned. Welp.

You would have still needed the drivers with the original plan, the LEDs would have had the power supplies working really hard and they wouldn't have lasted very long. You can still use the supply you have, grab 3 drivers and connect them to the supply with one LED on each.

So basically, connecting a 12v 1A LED to a 12V 5A PSU = inevitable destruction? I'm guessing Murk thought I'd be having all the LEDs in parallel at all times, but in reality I was just looking for a way to power "up to 3" LEDs, starting with one.

Yeah

To be entirely sure: Would I be able to hook (for instance) just 1 of these up to the 60W PSU that I already have, or would that overload the driver?

It will be fine, the driver will just pull whatever it needs and both your psu and LED should be happy. Just make sure you have something to dissipate the heat those LEDs will make, they will get quite hot.