How good are LED light bulbs? - my experiences

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daveB
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How good are LED light bulbs? - my experiences

Post by daveB » 30 Oct 2016 17:38

This is more for info than discussion. First off I will say I was an early adopter of CFLs - despite the fact they needed to warm up to get to full output. An essential requirement was they had to be warm white - cool white is too harsh and 'daylight' bulbs we find to be terrible. In the early years we had a few early failures but I have got into the habit of pencilling the installation date on the ceramic part - and recently where we have had to replace a couple more it turned out they had been in place for over four years.

Anyway that's the pre-wibble (I love that word - look it up). My daughter had to have a ceiling re-done in her rented property and they replaced the existing fitting with a Konica LED bulb - which gave an impressive amount of light (warm-white). So today I spotted that Wickes were selling a 3-pack of Phillips 9W LEDS for £9.99- so I bought a pack. The physical size is almost identical to the last 100 W incandescent I have in the spares box - and improvement of the other brand I've seen. (Note this is light bulbs - not downlighters).

The big question was - would I suffer from RFI? So I replaced the CFL in the room with all the radio equipment - tuned the SDR to 86 - 94 MHZ and observed the noise level at the low end of the band. It went up about 1dB. No change at the high end above 108 MHz - so for completeness the pendant lead now has a clip on ferrite bead fitted.

It has been reported that some LEDS emit loads of RFI - but it looks like the Philips ones are OK. The 9W LED is significantly brighter then the 11W CFL that is replaced (which is only a month old).

Just a bit of technical info - lamps are also rated by colour temperature in degrees Kelvin

2700K = extra warm white or warm white. This is the colour of the CFL and LEDs I have it is supposed to be the closest match to incandescent - Philips describe it as warm white
3000K = warm white
3500K = white
4000K = cool white. I find that if I am in meeting where the lights are this colour temperature I have a strong tendency to have to close my eyes
6500K = daylight matching - really blue white and awful.

DAvid
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John Faulkner, Skegness
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Re: How good are LED light bulbs? - my experiences

Post by John Faulkner, Skegness » 30 Oct 2016 17:45

That's very interesting Dave. Thank you for this.

Personally, I have never had any problems from LEDs, but I know some DXers have. We tend to buy ours from Wilkos, whatever brand they are, but they rarely blow.

Some of them do odd things after being switched off, like glow dimly for a few minutes, or flash every few seconds for about ten minutes, but no noise on MW or band 2 from them here.

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Julian Hardstone
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Re: How good are LED light bulbs? - my experiences

Post by Julian Hardstone » 30 Oct 2016 19:39

The trend now is for LED bulbs not to use a switching inverter but just to use a capacitor in series with the series diodes, so no RFI will be generated

I recently noticed that Screwfix have 14W GLS LED bulbs for £4.99 in cool or warm white, and I bought a set to replace the CFLs in the pendants at church. They claim to be equivalent to a 100W incandescent and, remembering the exaggerated claims for CFL equivalence I was sceptical. In the event they are easily equivalent to the old 150W bulbs. I immediately replaced most of the CFLs at home with these or 9W GLS, and I was pleased to see the new 3-pack deal on the 9W

The other thing I love about LEDs is that as long as there is no switching inverter there should be no detriment to life from switching on. For years I have tried to convince my wife and others that there's no point switching off a CFL if it's likely to be needed again in under a half-hour. I have never seen any figures relating to start up times for CFLs or tubes but my estimate is that you'd get at most 5000 starts for a CFL or 2000 for a tube, putting the cost at anywhere from 0.05 to 0.5p each time. She just can't get this, 'you're wasting electricity, aren't you?'

I recently bought a 3W globe bulb from the pound store and for the 1st time ever saw a specification for 'starts' with >10,000 claimed

Observe tubes in industrial and public buildings: if left permanently on they will last 2-3 years. We see this also in car indicator bulbs, always the first bulbs to go. That's why the first commercial application of LEDs in vehicles was for bus indicators. If an indicator fails the bus has to discontinue service immediately, at great inconvenience and cost to the operator

daveB
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Re: How good are LED light bulbs? - my experiences

Post by daveB » 30 Oct 2016 21:18

Hi Julian,

I looked up comparative figures for incandescent vs LED

60 W GLS = 700 lm
75 W GLS = 930 lm
100W GLS = 1055 lm

9 W LED = 803 lm
11 W LED = 1055 lm
13.5 W LED = 1521 lm

There will be a degree of non-linearity in the lumens per watt calculation as some of the power is used in the electronics around 2-3 watts by extrapolation and although the figures are for Philips LEDS the 9 watt one is not the same type.
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Andrew Webster,Wigan
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Re: How good are LED light bulbs? - my experiences

Post by Andrew Webster,Wigan » 31 Oct 2016 15:43

I bought a poundshop LED bulb out of curiosity and it wasn't bad no RFI either anyway I have a good stock of CFLs some years ago when they were being sold for 10 p.
They are Philips make and they do last and when they go it's the the tube envelope that goes not the capacitor in the SMPSU unlike the cheaper ones but I don't throw them away I take of the tube and use them for testing inverters/CFLs in PC monitors.

We have a fluorescent tube in our kitchen must be thirty years + old and replace the tube about 2-3 years and we leave it on all the time when it's dark lol.
Switching fluorescent tube/CFL lights on and off uses more power and decreases tube life quite considerably.

We have an dusk to dawn LED light outside our backyard this is mounted about 2 M below the band 1 aerial and when it comes on it makes my waterfall on the SDR go a bit more light blue can't see any difference on the signal meter and I can still see activity ok.

Now then it's best to buy a reputable make as there some dangerous LED lights out there as there is with other electrical stuff.

Andy
Receiving equipment: 2 Sony ST-S311, 1 Sony ST-SE520, 1 Sony ST-SE700 2 crossed FM 5s rotatable, 1 homemade FM 3 horizontal beaming S/E, 1 vertical FM 3 fixed beaming at Ireland, 2 element band 1.

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