Under cabinet LEDs fed by low voltage

[Roland Perry]

I'm looking at a possible design for kitchen under-cabinet lights where the wiring (daisy chaining from cabinet to cabinet) is low voltage.

In other words, have one transformer at the 'supply end' then feed the low voltage around to perhaps ten lights (in a chain, not a star).

The closest I can find is this one with four (which I presume could be adapted to be fed as a chain not a star):

And numerous others (even tens) with recessed lights; but I need surface-mounting ones.

Would prefer white rather than chrome.

[Bill Wright]

Surely voltage drop will be a major problem?

Bill

[Roland Perry]

In message , at 20:49:42 on Sat, 26 Oct

2013, Bill Wright remarked:

Not sure why; the wiring currently in the walls is normal mains voltage lighting wiring, which I presume is good for several hundred watts at

240v. Why wouldn't it also be good for less than ten watts at 5v (or whatever the LEDs are fed at)?

[Toby]

Because in any cable, you lose more volts the longer the cable, so a few volts at 240v isn't an issue, but 1 volt when you start at 5v is 20% lost.

This is why mains power is transmitted at very high voltages (400,000v as an example)

[Roland Perry]

In message , at 21:30:02 on Sat, 26 Oct 2013, Toby remarked:

I understand that, but what's the drop going to be in practice? The first link in the chain is about 3metres, and 1.5mm wiring has a drop of

30m/A/mv. The lights I'm looking at currently (not the one linked to earlier) run at 12v and consume 1.5w each, so that's a total of about 1.25 amps indicating a drop of around 0.1volt. Then there will be additional drops of about the same, or less because the current flowing in the chain gets progressively less.

The units say they run from 12v, so presumably have an internal regulator to reduce that (which will vary because of differing mains voltage input to the transformer supplied which claims to power up to five lights - so perhaps I'd need a different power unit) down to something suitable for the actual LEDs.

Anyway, assuming it does work from a Volt/Amp point of view, does anyone have recommendations for a pack of 10 (with daisy-chain, not star, supply) that they've used successfully?

[ARW]

R2CLED240-01

and google may help. It's a 2W LED mains powered surface mounted cabinet light.

[Roland Perry]

In message , at 08:38:39 on Sun, 27 Oct

2013, ARW remarked:

The internal PSU on those would solve the cosmetic issue. However, for 9 or 10, ~£180 is about three times what I was expecting to pay!

It takes me to a website "Fatal error: Call to undefined function anchor() in C:\Websites\ledgrouprobus.com.new\system\expressionengine\third_party\cat alogue\views\product-view.php on line 64"

[ARW]

Thats my fault. I saw a pack of 3 for 50 and had not realised your link was to a pack of 4 for 25 (I had a massive hangover this morning).

I did notice that the Robus site had a error. The ones I saw at 50 were on amazon.

[Bill Wright]

You didn't say you were using LEDS. In the absence of clear information I assumed you were using conventional 10W 12V lamps.

Bill

[Roland Perry]

In message , at 11:13:33 on Mon, 28 Oct

2013, Bill Wright remarked:

Not even in the title?

[ARW]

:-) And extending the cable by 3m using 1.5T&E will not be a problem. I'll try an have a look through a few of my catalogues later on to find some white ones for you. I am a bit busy at the moment