domestic lighting circuit

[MMUK]

In the IET magazine a while ago, it was mentioned that the US Deparment of Energy found in tests that the light output of LED lighting was mostly overstated, and in some cases by an order of magnitude. As for CFL's, the wattage equivalent figures at least need to be taken with a pinch of salt - IIRC there have been calls to re-assess them on the basis that they are not really equivalent in normal use, even if the total output measures the same, because of their different spectra.

Not sure I'd believe everything that the US says.

For instance I used to have two 4' twin fluorescent fittings in my workshop, a total of 144 watts. Even without diffusers the light output was pretty dismal. After startup load they were drawing just under 1A (pretty crap power factor figure of 0.6).

I've since replaced these with SMD LED strips. Three 5m strips (cut to 6x 2.5m strips spaced 1m apart) and a total of 450 LEDs running off a 300w PC PSU. These not only provide much better light, almost daylight, they only draw 0.72A with a power factor of 0.98 @240vAC (I've not yet tested the draw on the 12vDC side).

 

[monkeybiter]

What was the initial cost of the LED strips?

 

[Eric The Viking]

Well the power factor means you'll have a bigger bill than with the fluorescents!*

Do you have a link for the SMD strips (assume it's a flexi-PCA)? They sound interesting.

Neither do 'daylight' properly though, as they're not continuous spectrum. That said, white LEDs have long been thought good enough for TV and film lighting, so although they're three emitters usually, they can't be all that peaky.

Given they don't care about switching on and off, is it really that much more efficient to run them from a PSU than just a bridge rectifier?

What's the light spread like? Fluorescents can be a PITA if not in decent fittings - bare tubes really don't give a good light at all, but when they have reflectors and beam-spreading louvred grilles it can change.

It sounds really interesting though.

E.

*dunno about the new solid-state meters though.

 

[MMUK]

What was the initial cost of the LED strips?

eBay Hong Kong believe it or not and worked out about £7 per 5m strip.

 

[MMUK]

Well the power factor means you'll have a bigger bill than with the fluorescents!*

Not so. I have a proper calibrated meter monitoring electricity usage (not one of these cheap EON things, I got it from a power station when I refurbed the office block). Average consumption has actually gone down by around 25% on the lighting circuit alone.

 

[Eric The Viking]

Well the power factor means you'll have a bigger bill than with the fluorescents!*

Not so. I have a proper calibrated meter monitoring electricity usage (not one of these cheap EON things, I got it from a power station when I refurbed the office block). Average consumption has actually gone down by around 25% on the lighting circuit alone.

Interesting. I kept our old mechanical meter when it was replaced by an electronic one. Obviously, although it's properly calibrated, it won't correctly read anything that's not power factor corrected.

E.

 

[marcros]

Oh. btw do the low energy bulbs mean you actually read that low wattage as gospel?

If you find an example of a false claim I suggest you contact the ASA or trading standards as appropriate.

BugBear

I take issue with the idea that they are supposed to last for 10 years. They dont seem to in our house, although that may be factors other than the bulbs. perhaps the 10 year claim is a calculated one rather than real life usage.

 

[AndyT]

I've recently swapped the old 50 watt GU10 halogen spotlights in our kitchen for new LED equivalents which are only 3 watts each and am very pleased with them. I tried some a year or two back and was not impressed but these new ones have three rings of surface mounted LEDs in each unit. They cover a nice wide angle and give a warm white light so they really are an excellent upgrade to the old power hungry short lived bulbs. Cost was £8.50 each from our local electrical shop.

 

[monkeybiter]

I've recently swapped the old 50 watt GU10 halogen spotlights in our kitchen for new LED equivalents which are only 3 watts each .... Cost was £8.50 each from our local electrical shop.

Added to my 'to do' list

 

[RogerS]

As a slight aside, with all this talk about pushing out smart meters, you do all know that you can refuse to have one if you so wish ?

 

[MMUK]

As a slight aside, with all this talk about pushing out smart meters, you do all know that you can refuse to have one if you so wish ?

Only for so long. The actual meter and the board it is fitted to belong to the electricity company. In any case, there's still issues with the new metering system so there's no planned roll out date yet.

 

[RogerS]

As a slight aside, with all this talk about pushing out smart meters, you do all know that you can refuse to have one if you so wish ?

Only for so long. The actual meter and the board it is fitted to belong to the electricity company. In any case, there's still issues with the new metering system so there's no planned roll out date yet.

Ownership of the meter is irrelevant. You do NOT have to accept a smart meter.

http://www.which.co.uk/consumer-rights/ ... art-meter/

Poor security of those smart meters is also a tad worrying.

 

[mjcann]

Well the power factor means you'll have a bigger bill than with the fluorescents!*

Not so. I have a proper calibrated meter monitoring electricity usage (not one of these cheap EON things, I got it from a power station when I refurbed the office block). Average consumption has actually gone down by around 25% on the lighting circuit alone.

Interesting. I kept our old mechanical meter when it was replaced by an electronic one. Obviously, although it's properly calibrated, it won't correctly read anything that's not power factor corrected.

E.

Its nearly 50yrs since I did my elect theory, but I thought PF had no effect on normal domestic KWH meter, whereas it affected a KVAR device, or am I missing something with these new meters.

 

[Eric The Viking]

It's almost 35 years since I did mine. You may be right.

E.

 

[MMUK]

Its nearly 50yrs since I did my elect theory, but I thought PF had no effect on normal domestic KWH meter, whereas it affected a KVAR device, or am I missing something with these new meters.

Nope, you're quite correct

 

[MMUK]

Poor security of those smart meters is also a tad worrying.

Which is why a confirmed roll out date has yet to be confirmed.....