Replacement LED Driver for 36v 12w

[twixx]

Shocking, I know, but I’ve some Christmas Cluster Lights that operate from a 36v 12w PSU. https://amzn.eu/d/1ZLA3YR

The PSU gets warm and occasionally fails to power the lights, leading me to believe it is faulty/on its last legs.

I’ve ordered a 12W DC 34-46V LED Driver from https://ebay.us/m/6AD95b

I suspect this will be ok, but I just want to know.

A) it says 34-46v output. How will this be controlled to output at 36v?

B) could I use a 32v 9w PSU without damage? (Work? But less bright??)

C) which measurement should I not surpass? The 36V, 12W or both?

 

[Taylortwocities]

You’ve ordered the wrong power supply. You need a 36volt constant VOLTAGE psu.
The one you gave ordered is a CONSTANT CURRENT power supply.
It might work, but it could deliver a higher voltage.

 

[ericmark]

A LED is a current dependent device, so it needs a driver to convert them into being a voltage dependent device. A white LED is around 3 volts, and a red one around 1.2 volts, so if running from say 12 volts, one can use a resistor to convert to voltage from current and have 3 LED's and a resistor in series, then connect these up in parallel for a long strip of lights, but the resistor results in heat, and means not very efficient, but have 12 in series, and a current regulated power supply (driver) and it works far more economically.

So two different types of power supply, current regulated (variable voltage) and voltage regulated (variable current) and not really interchangeable.

 

[twixx]

Thanks folks, so a Meanwell APC-12-350 then?

I just found this on AliExpress: ￡5.93 | MEAN WELL LED constant current power supply APC-12 12W 350/700mA lighting low cost driver

MEAN WELL LED constant current power supply APC-12 12W 350/700mA lighting low cost driver - AliExpress 13

Smarter Shopping, Better Living! Aliexpress.com

a.aliexpress.com

I’d taken a punt on the VDC being controlled by a potentiometer. But I guess that’s incorrect.

If I was to run 36v 6w for example, that would work without frying them, but they’d be dull, right?

What about 36v and say 15w?

 

[twixx]

I’ve got that wrong again. That’s constant current above. The APV model is the constant voltage… so this

APV-35-36… however, this has 36V and 36W. Will it just output the Wattage required? (Ie 12…) or do I need a constant ‘both’?

I just found this on AliExpress: ￡38.10 | Meanwell LED Driver APV-35 Series meanwel 5v/12v/15v/24v/36v LED Transformer IP42 LED Power Supply Constant voltage Adapter

Meanwell LED Driver APV-35 Series meanwel 5v/12v/15v/24v/36v LED Transformer IP42 LED Power Supply Constant voltage Adapter - AliExpress 39

Smarter Shopping, Better Living! Aliexpress.com

a.aliexpress.com

 

[Taylortwocities]

however, this has 36V and 36W. Will it just output the Wattage required?

No no. The rated wattage is the maximum that the supply can deliver. It is the load attached that demands the number of watts it needs.

 

[twixx]

No no. The rated wattage is the maximum that the supply can deliver. It is the load attached that demands the number of watts it needs.

Sweet, cheers

 

[Jon c]

The only thing that will work is the first amazon link

Christmas Concepts® 36V 12W IP20 Electronic Transformer with Built in Timer Function - Suitable for Christmas Decorations : Amazon.co.uk: DIY & Tools

Christmas Concepts® 36V 12W IP20 Electronic Transformer with Built in Timer Function - Suitable for Christmas Decorations : Amazon.co.uk: DIY & Tools

www.amazon.co.uk

Christmas lights wirh multifunction flashing modes are wired with every other led in the same polarity ie. 1st led will be wired with 'correct' polarity, 2nd led will be wired 'reverse' polarity, 3rd will be 'correct' polarity again... and the pattern repeats. This is what allows the flashing functions to work and if you want them all steady on (no flashing) you need a power supply that has capability of switching the polarity around 100+Hz, which gives the illusion of the leds all being on at the same time, although really its just swapping the polarity very quickly all the time. Thats why you need a specific christmas light power supply.

Serious question - why did you not just buy the one in the amazon link when it appears to be a direct replacement?

 

[SUNRAY]

Oh good, reading this I was concerned no one would make this observation:

The only thing that will work is the first amazon link

Christmas Concepts® 36V 12W IP20 Electronic Transformer with Built in Timer Function - Suitable for Christmas Decorations : Amazon.co.uk: DIY & Tools

Christmas Concepts® 36V 12W IP20 Electronic Transformer with Built in Timer Function - Suitable for Christmas Decorations : Amazon.co.uk: DIY & Tools

www.amazon.co.uk

Christmas lights wirh multifunction flashing modes are wired with every other led in the same polarity ie. 1st led will be wired with 'correct' polarity, 2nd led will be wired 'reverse' polarity, 3rd will be 'correct' polarity again... and the pattern repeats. This is what allows the flashing functions to work and if you want them all steady on (no flashing) you need a power supply that has capability of switching the polarity around 100+Hz, which gives the illusion of the leds all being on at the same time, although really its just swapping the polarity very quickly all the time. Thats why you need a specific christmas light power supply.

Serious question - why did you not just buy the one in the amazon link when it appears to be a direct replacement?

These original powersupplies do run warm, I have something like 50 of them in various sizes, to date I've been happy (Lucky??) as I've had only one fail but it had been used on a much bigger set than designed for.

 

[Jon c]

Oh good, reading this I was concerned no one would make this observation:

These original powersupplies do run warm, I have something like 50 of them in various sizes, to date I've been happy (Lucky??) as I've had only one fail but it had been used on a much bigger set than designed for.

Yes I've noticed the same thing I do a fairly big christmas light display every year and they do get quite warm, I keep as many as I can outside in big weatherproof boxes which hopefully helps with heat dissipation thanks to the cold weather and also I just like to minimise the number of cheaply built power supplies inside my house....I have also had surprisingly few failures over the years