LED Under Kitchen Unit Lights

[sergeantash]

Hi all,

Just wondering if anyone has installed the LED RGB strip style lighting under their floor standing kitchen units (not wall units) and if so if they're happy with the concept overall?

http://www.ledlightszone.co.uk/led-tape/60-flexible-led-strips-non-waterproof-72w-30pcs.html

Also, did you go for the 30 or 60 LED per meter?

I'm looking to install this stuff with an RGB controller so that I can adjust the intensity and colour of the glow, currently I'm tempted by the 30 per meter as I believe that would give a more than sufficient ambient light.

Thanks,

 

[DetlefSchmitz]

I used some with 60 per metre. We are very happy with it. I used SOIC carrier tubing (Farnell) to hold it in and make it wipeable. Much cheaper than commercial mounting arrangements. Would never use anything else.

Edit: Ours is just plain (cold) white - though we have some colour changing led strip in the utility room (no windows). That's also good.

 

[sergeantash]

I used some with 60 per metre. We are very happy with it. I used SOIC carrier tubing (Farnell) to hold it in and make it wipeable. Much cheaper than commercial mounting arrangements. Would never use anything else.

Edit: Ours is just plain (cold) white - though we have some colour changing led strip in the utility room (no windows). That's also good.

Cool, thanks - do you think that 30pm would be sufficient as there's quite a cost difference in terms of the LED's and the supporting transformer which has to be bigger? Its only for illuminating the floor around the base units so it doesn't need to be floodlighting.

 

[DetlefSchmitz]

Oh misread that then. Our units are wall hanging and the leds replace the traditional flourescents. To illuminate the floor I think 30s would be perfectly ok.

 

[sergeantash]

Oh misread that then. Our units are wall hanging and the leds replace the traditional flourescents. To illuminate the floor I think 30s would be perfectly ok.

Thanks dude, much appreciated.

 

[Sponge]

http://www.ledlightszone.co.uk/led-tape/60-flexible-led-strips-non-waterproof-72w-30pcs.html

Searching for threads on kitchen lighting and this one came up. Are these any good? Or can someone offer another recommendation?

 

[sergeantash]

http://www.ledlightszone.co.uk/led-tape/60-flexible-led-strips-non-waterproof-72w-30pcs.html

Searching for threads on kitchen lighting and this one came up. Are these any good? Or can someone offer another recommendation?

Personally, I didn't bother buying the LED strip itself from an internet shop as they're so overpriced, I used Amazon instead. I ended up buying the following, and I'm really happy with all of it, its brilliant!

TRANSFORMER:
200W model: http://www.ledlightszone.co.uk/led-driver/74-12v-dc-led-driver.html

LED TAPE:
http://www.amazon.co.uk/gp/product/B00AA7GTJE/ref=oh_details_o05_s00_i00?ie=UTF8&psc=1

LED CONTROLLER:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=300777414274&ssPageName=ADME:L:OC:GB:3160

 

[SimonH2]

As it happens, I was installing LED strips for my mate yesterday.

Untitled

• SimonH2
• 4 Aug 2013
• 1

Untitled

• SimonH2
• 4 Aug 2013
• 1

The under cabinet spots are the Hafele ones supplied with the kitchen. The ones I was installing are the over cupboard ones and the under cab ones lighting up the floor. They are 5W/m & 60 leds/m. http://www.ledhut.co.uk/special-off...er-warm-white-best-price-on-the-internet.html

EDIT: The effect on the ceiling isn't as harsh as the camera makes it look !

 

[Sponge]

Thanks for the replies.

I bought a 150W driver and 4 x 2.5 warm white LED tapes from LED Hut and I'm currently working on the wiring diagram.

Unfortunately, the driver was damaged (mounting brackets bent and therefore possible internal damage) so I returned it today. Time will tell how the company handles the RMA.

The LED Hut website didn't mention voltage drop when running lengths in excess of 5m (they just talk about wattage) so I'm reading up on dual feeds/running in parallel.

I'll probably be back later today asking for some advice.

 

[SimonH2]

There are 2 issues with running long lengths :

1) Current rating. The strips are just very long and narrow flexible PCBs, which means there isn't a lot of copper. By the time you are end-feeding 5m of the tape my mate used, you're pulling over 2A at the supply end. That's a lot for what are fairly thin bits of copper.

2) Volt drop. Along with the low current capacity, the thin tracks will mean a resistance that could well affect voltage - thus the LEDs will dim slightly. On a long run this could be noticeable. It's not a case of (say) 1.2V drop would be a 10% drop - the LEDs themselves come to around 7-8V leaving about 4-5V to be dropped in the current limiting resistors. Thus a 1.2V drop would actually result in around 20-25% drop in LED current (because the LED voltage is approximately constant, so it all comes off whats' across the resistor), and hence brightness. 1.2V is a lot of drop, I just picked it to make the numbers easy.

A simple way to deal with the issue is to feed the strip at the centre - just remove any pre-fitted leads at the end, and solder a feed to the pads between each group of LEDs. I used some 2 core speaker cable (about 2mm^2 IIRC) - mostly because I happened to have it to hand. Separate feed to each side of the "U", and three sets of tails fit in the terminals of the 36W driver my mate got.

On "better quality" stuff, the LEDs are driven in constant current mode. The Hafele lights under the wall cupboards are 350mA, and are wired in series on each driver. Any voltage drop is irrelevant as long as you don't exceed the maximum output voltage the driver can deliver - the current (which is what sets the LED brightness) is fixed.

 

[ban-all-sheds]

Do strips which can be cut to "any" length work in constant current mode?

 

[SimonH2]

Do strips which can be cut to "any" length work in constant current mode?

No, all the strips I've seen/worked with are constant voltage. For 12V strips, there are three LEDs and a resistor in a cluster, at each end of the cluster are solder pads. Then multiple clusters are laid end to end. The PCB is actually made in sections around 2-3 ft long, then lengths are soldered together to make the longer lengths being sold.

If you look at the picture at http://www.ledhut.co.uk/led-strip-l...arm-white-best-price-on-the-internet-427.html you can see :
from the left, there is one LED, then a set of solder pads. Then the next group comprising an LED, a resistor, and two more LEDs. Then another cluster of 3 LEDs with their resistor, and then the next set of solder pads are off the right of the image.

So each set of three LEDs forms a self contained unit - 5cm long for 60 LED/m strips, 2.5cm long for 120 LED/m strips. You just cut between the solder pads. If you need longer lengths, just clean off the pads and overlap the strips so the underside of one end solders to the top side of the other.

It does vary though, so it pays to read the specs and read between the lines.
Some strips are regulated. I haven't handled any, but I believe they have a small regulator chip instead of the resistor. Often these quote a range of operating voltage. It's possible that some of these may even have the regulator set up in current mode - that would possibly make them non-dimmable for practical purposes as the regulators would fight the dimmer.
When I was doing out server room, one of the options I was offered had regulators, but the guy didn't really have the technical knowledge to say what he was selling. He did assure me they were dimmable, but I stuck with "regular" ones.

As it happens, the first ones I got (a short length to try out a few options) were rigid (in 1/2m lengths) and 24V. They had 5 LEDs per group.