Good day all!

I have bought 50 of these tiny LEDs. They're 12 Volt and I have a few low amp 12 V transformers but I still don't know how many amps I really need.

The supplier says they're 10 watt. Some other sellers say 9 or even 15 Watt! (and they all look the same to me)

They're very cheap and the light in the dark is very nice. Not much light even when pitch black but that's fine for the project.

Apparently it's a 5630 chip (but the supplier may not even know) and the date sheet I found online of the 5630 chip tells you each LED is 0.5 watt only. As these things contain 3 chips each I get to 1.5 watt in total. Similar chips may have a slightly higher wattage but whether it's 0.5 or 0.6 each doesn't make much difference.

However, there is a huge difference between 1.5 Watt per unit or 10 Watt per unit if you want to connect 50 units.

Anyone who can make a good guess what it would be?

 

Anyone who can make a good guess what it would be?

Why guess? Drive some at different currents until you get the brightness you want and calculate the power consumed. If you bought them from multiple sources, you need to do this for each batch. Hopefully the sources weren't so clueless that they mixed stock from multiple sources before selling them to you.

 

Thank you for your reply.

I just had a look at another datasheet online and that one too stated the 5630 as being 0.5 watt. Three times 0.5 is 1.5 watt only so I just don't get why all those sellers tell you it's 3 or 5 or 10 Watt. If the datasheet says 0.5 then the unit is 1.5 Watt, 99.9% right or not?

 

If the datasheet says 0.5 then the unit is 1.5 Watt, 99.9% right or not?

Are you 100% certain that the datasheet is for the LEDs you have? Package size doesn't necessarily dictate the power rating for an LED, it's brightness, maximum continuous current, maxim peak current, maximum reverse voltage, etc.

 

No, I am not. I just checked 2 datasheets (at random) which both contained a number of different LEDs. Both stated the 5630 chips as 0.5 watt. To me that sounded alright as the light is very faint. These cheap units costs EUR 6 or USD 7 for 10 pieces.

There are over 100 suppliers on Ali but the vast majority use the same pictures (as above) Some state the LED type (5630) and some do not. Most, but not all, mention the power consumption and that varies from 3 to 15 watt. If they're using the exact same pics/product one cannot be 3 and the other 15. I just found one supplier who actually said 1.5 watt but that's the only one. I think they don't really know.

 

There are over 100 suppliers on Ali but the vast majority use the same pictures (as above)

And the vast majority are clueless about what they sell.

 

Sure. They just sell whatever they get their hands on. Because of the enormous differences (1.5 or 15 Watt per unit) I decided to check some datasheets and as the light really is faint I though two things: probably indeed a few Watt only but I had better check Allabout circuits.

 

"Watts" has become a marketing term.

If they told you the actual power consumed, you would no think they are "Powerful"

The term has come to mean "Equivalent light output to XX Watts of incandescent lighting"

<Measure it> <Know it>

 

but I had better check Allabout circuits.

AAC members aren't mind readers or all knowing. Don't make assumptions. Take some measurements so you'll know.

 

Ok, will take your advice and post the outcome here in a few days!

 

The maximum power is determined by the temperature rise.
If they are in a metal housing which is in good thermal contact with the LEDs then the maximum power is when the cases are too hot to keep in your hand.

 

"Cheap" and "Ali" mean that the specs and quality are very poor.
The sellers make more profit when they make lies about the specs.

 

Well, 10 units for 7 USD, there is no money in that. That even includes shipping.

7 years ago I bought different ones, fairy tale lights with a transformer integrated and most have worked fine for all that time, 7 days a week, 10 hours a day. So 25.000 hours for a few dollars is +++ with me. This time (we have moved) the set up is different so small 'spot lights' instead of 'Christmas' decoration!

 

For many LEDs, the range between dim and damaged is about 0.5V. You might try increasing current and mapping out Vf. Get a dim glow, measure Vf, and then incrementally increase current to give you Vf increases of ≤ 0.1V in Vf. Stop before you reach 0.5V above dim.

 

Right, I make things out of wood so I know very little about electronics! I just bought the first multi-meter in my life and the set up is:

Power goes to the spot light
Negative from the spotlight goes to plus of the multi meter
Negative of the multi meter goes to negative of the 12 V transformer

The spotlight now works but extremely faint and the meter shows:

Top, this scale is green and runs from 200 (left) to 0 (right) I think this is the resistance (My set up reads 7 here)
Then there is a black scale that runs from 0 to 250 and is called V.mA (My set up reads 100 here)
Below is a red scale from 0 to 10 and is called AC 10V (I'd say not applicable)
And at the bottom is a scale from -20 to +22 and the name is DB (which doesn't make sense to me at all as Decibels have little to do with this all)

I set the meter to 10 DC as that is the nearest to 12





Is this right and if so how can I calculate the wattage?

 

I make things out of wood so I know very little about electronics!

We prefer schematics, block diagrams, and, if absolutely necessary, wiring diagrams.

The meter you bought is pretty low quality. Hope you didn't pay too much for it. Even the $10 Harbor Freight DVM, which you can often get for free with a purchase, would be better. At 2k ohms/volt sensitivity, it might be adding a significant load to any circuit you might want to measure.

 

What is the meter set to on the dial?

 

Yeah, USD 5. may never use it again, just want to know the power consumption so I can buy the appropriate (number of) transformers. If all suppliers had shown the same technical details I would not have bothered. Now I am worried blowing up a transformer at night.

The dial was set to DC and to 10.

 

I set the meter to 10 DC as that is the nearest to 12

For a voltage reading, and most things your meter can measure, the meter probes are in parallel to the thing you're measuring. The circuit is functioning normally and you apply the probes. The meter is then also part of the circuit, but only for the tiny amount of current required to make the measurement.

The arrangement you described makes the meter a vital part of the circuit and is appropriate only for measuring current. Your dial has a setting to choose a current reading and it may also have a different socket for the leads. This enables a larger current to flow through the meter than normally. Be careful about the maximum current - you could burn up your meter or at least an internal fuse if the current is excessive.

 

There is only one socket possible and I have set it up now in parallel.

Light connected to the 12V transformer.

Dial set to 10 DC and the meter goes wild, all the way to the right and passed that.

When set to 50 DC the meter goes out gently to a resistance of 25 Ohm (top scale)