LED under cabinet lights

[ezridr60]

Many moons ago when I built this place I installed low-voltage, 12VDC undercabinet lighting. About 10 pucks fed off a common power supply. G4 bayonet xenon bulbs. While the life of these bulbs is much greater than the halogen bulbs they replaced, I’d like to change them out for LED low voltage pucks using my existing power supply. The problem, I don’t know the polarity of the wires coming from the power supply. Didn’t make any difference with the current setup. The question, are LEDs sensitive to wire polarity?

Why do I want to change the current setup? Even though the xenon bulbs last a lot longer they still occasionally burn out. At my advanced age, limited mobility, and crappy eyesight, trying to look thru triple focal lenses, getting the bayonet bulb into the fixture is a chore.

I’d just like to keep the existing wiring if possible.

 

[AffableCurmudgeon]

LEDs are sensitive to polarity. That said, any LED pucks you buy will be marked for the polarity they use. Amazon is full of options.
As for using your existing power supply, you can find the polarity of the power supply wires using a digital multimeter. Connect the red and black leads from the multimeter to the two wires coming out of the power supply. If the multimeter reads 12v, the wire connected to red lead is positive. If the multimeter reads -12v, the wire connected to the black lead is positive. Connect your new pucks to the power supply using their marked polarity.

Check the power supply‘s amp rating. Make sure that you don’t exceed that when you connect LED lights to that supply.

 

[mrbill55]

Why replace the whole puck, when a retro fit LED bulb is all that is needed? Big box stores have them in stock, simple, easy, elegant solution from the "less is more" mindset.
Did this recently to our current, 1990's retro fitted kitchen, use them daily for months, without any issues.


Bill S.

 

[Innovate1]

LEDs are sensitive to polarity. That said, any LED pucks you buy will be marked for the polarity they use. Amazon is full of options.
As for using your existing power supply, you can find the polarity of the power supply wires using a digital multimeter. Connect the red and black leads from the multimeter to the two wires coming out of the power supply. If the multimeter reads 12v, the wire connected to red lead is positive. If the multimeter reads -12v, the wire connected to the black lead is positive. Connect your new pucks to the power supply using their marked polarity.

Check the power supply‘s amp rating. Make sure that you don’t exceed that when you connect LED lights to that supply.

No way you are going to overload the power supply when switching to LED fixtures unless you massively upsize the fixtures or add a huge amount more - like at least several times what you have now. LEDs take way less current than what is being replaced.

 

[ez-duzit]

Use a VOM to check polarity.
Amazon sells some remarkable LED strip lights that are very low profile, have their own switch, and are very bright. Priced at 4 for $20.

https://www.amazon.com/dp/B094R1VNQX/?tag=atomicindus08-20

 

[dcg9381]

Partially finished. Components are from birddog lighting, recommended by the guy that built these cabinets. You can go nuts if you want... Zero failures in the last 3 years.

 

[ezridr60]

LEDs are sensitive to polarity. That said, any LED pucks you buy will be marked for the polarity they use. Amazon is full of options.
As for using your existing power supply, you can find the polarity of the power supply wires using a digital multimeter. Connect the red and black leads from the multimeter to the two wires coming out of the power supply. If the multimeter reads 12v, the wire connected to red lead is positive. If the multimeter reads -12v, the wire connected to the black lead is positive. Connect your new pucks to the power supply using their marked polarity.

Check the power supply‘s amp rating. Make sure that you don’t exceed that when you connect LED lights to that supply.

Thanks for the info!

 

[dave*99]

Are you sure your power supply is DC? Halogen bulbs would not require DC. Take a good look at the power supply.
If it turns out it is AC, the polarity won't matter.