LED tubbes as replacement for fluorescent tubes

[yetloh]

I have daylight fluorescent tubes in my workshop and like them a lot but I have recently had contact problems on them and trouble getting them started when the workshop is really cold so am considering LED fluorescent replacement tubes which appear to offer similar light qualities (very wide angle of emission unlke conventional LEDs) but use less power and don't buzz or flicker like some of my tubes do, while using l having a longer life. They are pricier than fluorescent tubes but might be worth it if the claims are true. Does anyone have experience of them please?

Jim

 

[Phill joiner]

Yes Jim I replaced 15 tubes for led ones and it's made a massive difference in the workshop. I need sun glasses in there now. Another benefit are that bugs are not attracted to them or flying around them. I had a massive issue with wasps a few years ago. Now the led lights are fitted no wasp attacks. Well worth the investment mate.

 

[mseries]

This is timely as I have been considering swapping a 1500mm 58W tube for a LED one. Which LED one have people used ?

Most seem to be around 2000lm to 2400lm wheras a 58W T8 is about 5000lm, I realise that LEDs don't send the light up and a I don't need that but is the light output equivalent in real use ?

I really appreciate an actual recommendation.

 

[Glynne]

Can you simply replace like with like without changing the fittings?

 

[mseries]

Can you simply replace like with like without changing the fittings?

depends on your fitting. With magnetic ballast you replace the starter with a dummy one that's supplied - so it;s a very easy job. Electronic ballast needs by passing by rewiring the fitting. Plenty of information on line at places that sell LED tubes

 

[Eric The Viking]

I like LEDs, but be aware that they might flicker, giving strobing effects on machines (under rare circumstances making it look as though cutters are stationary when they're actually spinning!).

LEDs are diodes, so only pass current in one direction. LED arrays intended for mains use have circuitry to take advantage of both halves of the mains waveform (usually), otherwise the flicker would be quite unacceptable (50Hz, and off for about 51% of the time!). With a cheap circuit, they will still go completely off for "dark pulses" at 100Hz frequency.

Fluorescents also switch off 100 times/sec, but the phosphor chemistry chosen means the glow of light persists during the off periods, so the flicker is not as pronounced - more a pulsing variation in brightness. It was a nuisance in the days of film movie cameras (there were special boxes that synchronized cameras with the mains so the flicker didn't show on-screen).

Cheap LEDs don't dim, they go completely off, 100 times/sec in the UK, 120 times/sec in the USA, so the strobing effect is a lot stronger than that of fluorescents.

I have an Ikea 'goosneck' table lamp that does this (single ultra-bright LED), and all the LED spotlights in the downstairs loo do, too. They're 12V halogen bulb replacements. If you run the tap, you can clearly see the strobing, as the stream of water into the sink appears to pulse. Other 'streams of water' do it too, which is a bit disconcerting (speaking as a bloke!).

It may not be a problem, but be aware of the effect just in case. Fluorescents used to be banned from lathes in factories, for exactly that reason - they could cause nasty incidents.

FWIW, I've recently replaced two ceiling light sets in the house with all LED (pretend candle bulbs and pretend 60W globes), and I'm really pleased so far: bright, good quality light, and OK-ish colour for photography too (good enough for non-critical colourimetry). I think they're cheap enough to be useful now, but I've no idea how long they might last.

E.

 

[Gerry]

I have an Ikea 'goosneck' table lamp that does this (single ultra-bright LED), and all the LED spotlights in the downstairs loo do, too. They're 12V halogen bulb replacements. If you run the tap, you can clearly see the strobing, as the stream of water into the sink appears to pulse.

Leds don't flicker, the driver circuit will cause it if it is very badly designed or not suitable for LED.
When you replaced the 12v halogens in the Loo did you just plug them straight in to the bulb holder?
If so your driving them from a Halogen transformer/driver which will output AC and not the required DC. This means that the LEDs are only lighting up for half the time and as LEDs are semiconductors they are current dependent and need a DC constant current source.
You need to replace the Halogen drivers with dedicated LED drivers.

Gerry

 

[Racers]

I believe the lamps have built in rectifiers etc, the ones I have fitted do as they are running from transformers with out flickering.

Pete

 

[Eric The Viking]

If you drive an LED from a bridge rectifier, it flickers at 100 Hz in the UK. The voltage drops to zero 100 times per second. It's not off for very long in the cycle, but it IS off.

If you drive it from constant DC, i.e. from a battery or a smoothed DC supply (basically adding a capacitor across the rectified output), It doesn't flicker. This is because the voltage never drops below the LED's forward voltage.

There's nothing clever about an LED "driver" usually - just a low voltage smoothed PSU of some sort. Presumably some are smoothed and some aren't.

It's slightly different if you 'dim' LEDs - all bets are off there, as they only dim over a narrow range (and it's very non-linear) if you simply alter the voltage.

The usual practice in electronics years ago was to feed them asymetric square waves at a fairly high frequency (say 1000Hz) and vary the mark-space ratio. The eye perceives the on-off ratio as dimming. This is also done to extend battery life - same approach, same effect.

I have mains-driven LED units in the ceiling light above me as I type. They don't seem to flicker, however it's still daylight too. I assume they have a series resistor, rectifier, and capacitor to prevent it, however there's hardly any room in a standard 3/4" bayonet cap to fit that lot, let alone in the glass envelope part. I'm not going to break one just to find out.

The Ikea unit definitely flickers. It's a single LED, and the body of the fitting forms the heatsink. In that case, the 'LED driver' ought to isolate it too, as the gooseneck and lamp head are metal. I am skeptical about this though, as the whole thing only costs 10 quid (good value mind!), and the PSU is a wall-wart with no visible earth connection and only two wires to the lamp itself. There doesn't look to be room for a traditional transformer, and you'd think a switch-mode supply would be too expensive for the price.

IIRC, the thing about fluorescent machine lights in factories was because the overall noise level meant you couldn't tell if the machine was running by the noise alone (the whole place was loud).

 

[Phill joiner]

I've got to say I have no issues with flicker at all in my workshop. Even tried running the tap in the kitchen and no flicker here.......

 

[niagra]

Just replaced two of my 8 foot ones with LED tubes. 38W instead of the previous 100W, the light seems to be more natural without a yellow tinge to it and is much brighter. Only change to the fittings was to take the starters out. I'm really happy with mine and will replace the other two when they expire.

Dario

 

[Jacob]

I have daylight fluorescent tubes in my workshop and like them a lot but I have recently had contact problems on them and trouble getting them started when the workshop is really cold so am considering LED fluorescent replacement tubes which appear to offer similar light qualities (very wide angle of emission unlke conventional LEDs) but use less power and don't buzz or flicker like some of my tubes do, while using l having a longer life. They are pricier than fluorescent tubes but might be worth it if the claims are true. Does anyone have experience of them please?

Jim

If your tubes don't light promptly they may just need new starters - little cartridge things which stick out of the side, one for each tube. Twist counter clockwise to release. If that doesn't do it it's new tubes.

I'm interested in the LEDs though and might replace mine as they go.

 

[AndyT]

I assume they have a series resistor, rectifier, and capacitor to prevent it, however there's hardly any room in a standard 3/4" bayonet cap to fit that lot, let alone in the glass envelope part. I'm not going to break one just to find out.

For Eric, and anyone else wondering what's inside all this modern electronic stuff, I recommend http://bigclive.com/ and especially his YouTube channel. He buys stuff from pound shops and eBay and takes it apart, analysing the electronics as he goes, in a soft Scottish accent.

Eric, if you haven't already seen his stuff, I apologise in advance for lowering your productivity! There are lots of videos - including plenty of LED related ones.

 

[Eric The Viking]

For Eric, and anyone else wondering what's inside all this modern electronic stuff, I recommend http://bigclive.com/ and especially his YouTube channel. He buys stuff from pound shops and eBay and takes it apart, analysing the electronics as he goes, in a soft Scottish accent.

Eric, if you haven't already seen his stuff, I apologise in advance for lowering your productivity! There are lots of videos - including plenty of LED related ones.

You HORRID man!

I have just wasted 20 mins watching videos, and I should have been tidying the kitchen prior to The Return From Work.

So I'm in trouble. But it was fun though

E.

 

[yetloh]

Thank you everyone, that is most illuminating

Phil,

Do you recall the make of your repacement tubes and where you got them from?

The apparent brightness difference seeems a bit of a contradiction given theat the stated light output of LED tubes is somewhat lower than fluorescents but may be to do with the deterioration in light output of fluorescents over time which I understand can be up to 50%.

Eric, I'm keen not to have an obvious flicker, but users don't seem to be complaining about it. As for strobing, my worshop has separate rooms for hand work and machines and I'm considering LEDs for the latter at the moment which ha only a pillar drill. As this detroys the peace and quiet I don't think I'm ever likely to be fooled into thinking it isn't going. My machine shop doesn't have a lathe and I don't think the bandsaw or p/t are likely to be a problem.

mseries, I think the led replacement tubes have translucent external tubes which ensure that the light emission angle is not much different from that of a fluorescent tube.

Thanks, but I have tried replacing the starters to no avail. The fittings are now quite old so it my be to do with poor conracts at the ends of the tubes which are not easy to access. I might be better off with new fittings.

Jim