LED Bulb Thread

Mark M · 4 Jun 2018 at 21:10

Could anyone confirm a dimmer to control 8 gu10 led bulbs for a bedroom. I need to buy the bulbs too.

Currently I have 8 standard gu10 and a non dimmable switch so need something that can run on the existing wiring.

Thanks in advance.

jpaul · 5 Jun 2018 at 18:33

I don't know about a dimmer anymore, varlight vpro seems to monopolise market but (see chart i posted) osram says they don't have a good dimming range,
and may need one of these too https://www.varilight.co.uk/configurator/product.php?code=YAGF-P
(I had thought they were a no brainer)

for gu10's I like the lohas surface mount with the good 120 angle - 8 of those would be 4000lm, a bit much for a bedroom,
but maybe they have lower power eg. https://www.amazon.co.uk/Dimmable-Beautiful-Replacement-Technology-Warranty/dp/B01GL662GW

doodah · 25 Jun 2018 at 11:50

I haven't the foggiest about bulbs but need some advice. My bedroom has 4 x GU10 50W bulbs and they really aren't bright. It just feels like 4 corners of my room aren't lit well enough, unless you're directly below one of them. Any way, one has packed it in and I want to replace them all. My God, why do bulbs need so many variables

. I just want something that is brighter and I presume dimmable (dimmer switch). Problem is, the usual place has so many variants it's hard to tell which are actually good. Any recommendations?

eviled · 27 Jun 2018 at 09:57

what you need is a wider beam angle to light your room more evenly, bulbs and fittings play a part so you may be limited by how much you can acheive

maybe try a couple of different ones from screw fix and return if no good

glitch · 30 Jun 2018 at 16:12

Any recommendations for 4000K bulbs for ceiling fittings? Need to be dimmable, decent CRI and preferably bayonet, but I'm going to assume E27 is going to be the readily-available option.

I've got a couple of Osram Super Star to test which seem decent, but just wondering if there is anything out there which is better.

sityeuropa · 7 Jul 2018 at 23:08

Any G9 bulbs 5w> that don't have the strobe flicker effect?

Its immediately clear if you set your phone camera to 1/500 what is actually going on with a lot of them.

Then there is another bulb I have, Diall E27 9.6W which doesn't flicker at all no matter what shutter speed. That's when you know you have a good bulb.

G9 at 1/500 shutter speed (Be warned much flicker)

E27 Diall at 1/500 (no flicker whatsoever)

Any of you post your G9 bulbs at 1/500? Whats the flicker like.

jpaul · 8 Jul 2018 at 15:45

sityeuropa said:
Its immediately clear if you set your phone camera to 1/500 what is actually going on with a lot of them.

the low 'flicker' may be down to phosphor persistance - have phosphor on the globe bulbs's I have purchased.

for the 'flicker' g9 (no phosphor it appears) do you get it with a single bulb ?
phone cameras afaik are also not collecting raw images at 500hz so their interpretation can be misleading (eg interlaced capture)
You usually need at least 500hz (pwm), on any led bulb, to avoid flicker on moving objects, and, if the refresh was say 1200hz with a duty cycle of 75% you would perceive flick with a 500hz sample rate phone (nyquist applies ?) , so the phone is not indicating frequency, and the flicker will not cause any problem for a human.

You don't have a dimmer in the circuit ? since these could be interacting with bulbs too with uneven trailing edge cuts, not sure how tight the tolerance is on 50hz mains supply either.

sityeuropa · 8 Jul 2018 at 19:08

jpaul said:
the low 'flicker' may be down to phosphor persistance - have phosphor on the globe bulbs's I have purchased.

for the 'flicker' g9 (no phosphor it appears) do you get it with a single bulb ?
phone cameras afaik are also not collecting raw images at 500hz so their interpretation can be misleading (eg interlaced capture)
You usually need at least 500hz (pwm), on any led bulb, to avoid flicker on moving objects, and, if the refresh was say 1200hz with a duty cycle of 75% you would perceive flick with a 500hz sample rate phone (nyquist applies ?) , so the phone is not indicating frequency, and the flicker will not cause any problem for a human.

You don't have a dimmer in the circuit ? since these could be interacting with bulbs too with uneven trailing edge cuts, not sure how tight the tolerance is on 50hz mains supply either.

Thanks, no dimmers on the circuits. I definitely feel a strobe and dizzy effect on them G9 Leds, waving my hand makes my eyes funny. My phone at the same frequency doesn't pick up flicker on the E27 bulb and to my eyes I don't get any strobing effect on that one.

Anyone else try this?

jpaul · 8 Jul 2018 at 20:12

thinking further the phone experiment is meaningless -
all we learn is that the Diall bulb has a refresh rate that is a multiple of 500fps, and the G9 does not.
so the diall could be 1000hz and the g9 1200hz ... so there could in fact be more stroboscopic effect on the G9
maybe someone can point you to a web link .. maybe read this about PWM

EDIT: easier than i thought ..
you look at bulb every 2ms = 500hz/fps , diall has a freq of 1000 and is alsways on ... but g9 is actually faster but has a freq of 1666 so simetimes off/sometimes on

you see ?

sityeuropa · 8 Jul 2018 at 20:31

jpaul said:
thinking further the phone experiment is meaningless -
all we learn is that the Diall bulb has a refresh rate that is a multiple of 500fps, and the G9 does not.
so the diall could be 1000hz and the g9 1200hz ... so there could in fact be more stroboscopic effect on the G9
maybe someone can point you to a web link .. maybe read this about PWM

If I scroll up and down my shutter speeds which there are many. The Diall doesn't flicker at all.

jpaul · 9 Jul 2018 at 09:45

what is the phone and the lcm of the shutter speeds. ?
agree a gopro h5 ,say, with 120, 90, 80, 60, 50, 48, 30, 25, 24 fps gives 3600hz, so if there was genuinely no strobe for a bulb (inspect frames ?) then that would suggest frequency of pwm is high ... assuming that bulb is not on constantly and uses a pwm .. with non-dimmable bulbs I suppose they have that, constant, option.

I make a trade-off take a high-cri/90+ non-dimmable bulb, over a dimmablecri80 every time

sityeuropa · 9 Jul 2018 at 10:14

jpaul said:
what is the phone and the lcm of the shutter speeds. ?
agree a gopro h5 ,say, with 120, 90, 80, 60, 50, 48, 30, 25, 24 fps gives 3600hz, so if there was genuinely no strobe for a bulb (inspect frames ?) then that would suggest frequency of pwm is high ... assuming that bulb is not on constantly and uses a pwm .. with non-dimmable bulbs I suppose they have that, constant, option.

I make a trade-off take a high-cri/90+ non-dimmable bulb, over a dimmablecri80 every time

So to ensure less strobing do non-dimmable bulbs give the best chance? My phone is Galaxy S9.

1/24000, 1/12000, 1/8000, 1/6000, 1/4000, 1/3000, 1/2000, 1/1500, 1/1000, 1/750, 1/500, 1/350, 1/250, 1/180, 1/125, then longer shutter speeds.

Super slow motion 960fps also gives no flicker on the Diall E27 9.6W.

G9

jpaul · 9 Jul 2018 at 15:44

sityeuropa said:
So to ensure less strobing do non-dimmable bulbs give the best chance?

yes I think that maybe the case, as soon as it is dimmable they have to turn the bulb on and off at high frequency use PWM - is the g9 a dimmable bulb. ?

sityeuropa said:
If I scroll up and down my shutter speeds which there are many.

I had, wrongly, thought your original photo was an upload of a slo-mo playback of a high frame rate picture, to explain the horizontal bars (curious these are gone at 960fps, which could also be at near 1/500th)
but seems (like iphone x too) and most phones they have a rolling shutter, so pixels for different parts of picture are scanned sequentially as opposed to at the same time, like a mechanical/global shutter can do.

Does the flicker go away, at slower than 1/500 shutter speeds, for g9. ?
yes, it is annoying if you cannot use a phone reliably for videos or stills under indoor lighting, with bigger aperture/sensors on new phones, would have hoped to use higher shutter speeds.

sityeuropa · 9 Jul 2018 at 16:14

jpaul said:
Does the flicker go away, at slower than 1/500 shutter speeds, for g9. ?
yes, it is annoying if you cannot use a phone reliably for videos or stills under indoor lighting, with bigger aperture/sensors on new phones, would have hoped to use higher shutter speeds.

The flicker goes away at slower shutter speeds but this is around eye rate which is a problem as I can see the strobe effect with my eye when moving my arms around or turning my head quick.

I just bought for a test from Toolstation.

Integral LED G9 Capsule Lamp 3.2W Warm White 300lm

No flicker whatsoever from this one at 960fps or when using any shutter speed on my phone camera.

So it seems the cheap ones on eBay you get what you pay for. I'm going to have to shop around to find the right ones it seems.

jpaul · 10 Jul 2018 at 18:04

subsequently saw this utube
LED bulbs that flicker, and CFLs that almost never did
which puts me off filament type leds.

also https://www.youtube.com/watch?v=Qym5-126BDY

I believe all this is showing is the refresh rate of the light at whatever cycle speed is used. If you live in 60 cycles per second land then a shutter speed that is 60 or a multiple of will remove the bands. If the shutter speed is anything but a multiple of 60 then you see bands. Same applies if you live in fifty cycles land

.

sityeuropa · 10 Jul 2018 at 21:34

jpaul said:
subsequently saw this utube
LED bulbs that flicker, and CFLs that almost never did
which puts me off filament type leds.

also https://www.youtube.com/watch?v=Qym5-126BDY
.

I've just ordered a filament type eek, I'll let you know.

sityeuropa · 11 Jul 2018 at 22:13

Just tried some B22 LED Filament from LVWIT, they seem great, no flicker whatsoever.

Then some Bonlux B22 normal LED which are fine also.

Tackle_Berry · 1 Aug 2018 at 18:54

Looking to replace my current GU10 5w warm white bulbs for ones that give a very bright cool white with a widebeem angle any suggestions? Non-dimmable is fine. I tried the LAP ones from Screwfix but at 5w and a 36 degree angle the light was too concentrated and not bright enough.

Stu · 2 Aug 2018 at 10:25

Creedmoor said:
Looking to replace my current GU10 5w warm white bulbs for ones that give a very bright cool white with a widebeem angle any suggestions? Non-dimmable is fine. I tried the LAP ones from Screwfix but at 5w and a 36 degree angle the light was too concentrated and not bright enough.

https://www.screwfix.com/p/lap-cosm...-led-downlight-matt-white-500lm-4w-240v/3432x

60° beam angle, 4000K cool white

PaulCa · 2 Aug 2018 at 13:05

I did this recently, replaced all my lightbulbs with LED ones.

A few lessons learnt though. For the kitchen I went for cold white 6W bulbs. Cold white is horrible. It's cold, sterile, uninviting. Better to stick with the warm white.

Also the beam angle is important to note. The ones I bought for round the house have a diffused cover and no real beam angle at all, which is great, they are all 3W or 5W warm white 240V. The kitchen ones are 12V and very much spot lights and so I have 4 pools of cold white light and dark patches between them.

I think I may have to replace those.

Also I have one that cuts out in the kitchen. I don't think it's overheating, but it randomly switches off for a few minutes and back on. Time to replace all 4 I think.

Still total cost to replace 20 bulbs was only £45 and I expect that will pay for itself in a year or less.