Thread: Fletty's new shed WIP ....or is it a retrospective??

Originally Posted by fletty

Those 1200 x 300 LED lights are back on sale...

https://www.ebay.com.au/itm/New-40W-...r=590898361598

Ive just ordered another one....... I know, I know!

Originally Posted by QC Inspector

When I lit my shop I used daylight too. I aimed for 1,000 lumens per square meter. I am glad I did. ......

Hi Fletty, QCI and others.

Every time I add another fluoro to my shed I have welcomed the increased luminance, but that enthusiasm always fades and I need more yet lighting. I think uniform lighting of 1,000 lumens at bench height would be ideal, or so my reading tells me. Time to bite the bullet and do it properly.

Most 1200 mm LED panels or 1200 mm T5 fluoros are rated at 3800 - 4000 lumens. But that is at ceiling height, not bench height. How do I calculate the lumens that should reach my bench? What is the dispersion/attenuation or whatever?

There must be a better way than just adding more lights until it seems right.


Cheers

Graeme

Originally Posted by fletty

.... if you can't see the bright side, polish the dull side

You cannot polish a terd, ..... but you can add spangles!

Originally Posted by GraemeCook

You cannot polish a terd, .....

My dogs seems to give it a good try . . . . . . .

Originally Posted by GraemeCook

Most 1200 mm LED panels or 1200 mm T5 fluoros are rated at 3800 - 4000 lumens. But that is at ceiling height, not bench height. How do I calculate the lumens that should reach my bench? What is the dispersion/attenuation or whatever?

There must be a better way than just adding more lights until it seems right.


Cheers

Graeme

Hi Graeme, the only formulae to calculate light fall off that I have used, relate to point sources of light where the light drop is the inverse square of the distance but I haven’t yet seen any formulae for plate sources such as LED panels, so I am now very clearly in the suck-it-and-see camp too! It is nice now that I am fully retired and, for some reason, no longer expected to review, calculate nor justify anything I do?
However, 2 problems I now have are

• A mix of warm and daylight LED panels which will soon be fixed AND
• A currently ongoing mix of fluoro and LED which I mostly notice when photographing in the shed

My next (unjustified, uncalculated) change will be to simply replace the fluoros with daylight LED tubes. Job done

Originally Posted by fletty

Those 1200 x 300 LED lights are back on sale...

https://www.ebay.com.au/itm/New-40W-...r=590898361598

Ive just ordered another one....... I know, I know!

Does anyone know if there is any advantage of these over something like a traditional batten LED: SmartBright LED Batten G2 Battens - Philips Lighting

I was thinking (and have bought) a couple of these to test with: BN012C LED20/CW L1200 G2 SmartBright LED Batten G2 - Philips Lighting

Whilst they're only 2000 lumens, they're also only around $25, so it'd be quite easy, given their size and price, to mount more of these to equal the luminosity of these AEG panels, yet I keep seeing these used and linked, so I"m thinking there has to be a good reason for that?

The larger the light source the softer the shadows, so because the panels are much wider than the battens the light will be much more even and the shadowing would be almost non-existent.

Originally Posted by Midnight Man

Does anyone know if there is any advantage of these over something like a traditional batten LED: SmartBright LED Batten G2 Battens - Philips Lighting

I was thinking (and have bought) a couple of these to test with: BN012C LED20/CW L1200 G2 SmartBright LED Batten G2 - Philips Lighting

Whilst they're only 2000 lumens, they're also only around $25, so it'd be quite easy, given their size and price, to mount more of these to equal the luminosity of these AEG panels, yet I keep seeing these used and linked, so I"m thinking there has to be a good reason for that?

Gday Midnight, the way I see it, a point light source (bulb) creates harsh shadows on a work surface, a line source (fluoro, incandescent or LED tube) creates less shadow than a point source but a sheet source ( LED plate or skylight in daytime) creates much less again.

Originally Posted by fletty

Hi Graeme, the only formulae to calculate light fall off that I have used, relate to point sources of light where the light drop is the inverse square of the distance but I haven’t yet seen any formulae for plate sources such as LED panels, so I am now very clearly in the suck-it-and-see camp too! It is nice now that I am fully retired and, for some reason, no longer expected to review, calculate nor justify anything I do?

There are a couple of on-line apps that will work it out for you - can't remember where they are are or even the search terms I used to find them. If I remember I will post.

Originally Posted by GraemeCook

Every time I add another fluoro to my shed I have welcomed the increased luminance, but that enthusiasm always fades and I need more yet lighting. I think uniform lighting of 1,000 lumens at bench height would be ideal, or so my reading tells me. Time to bite the bullet and do it properly.

Most 1200 mm LED panels or 1200 mm T5 fluoros are rated at 3800 - 4000 lumens. But that is at ceiling height, not bench height. How do I calculate the lumens that should reach my bench? What is the dispersion/attenuation or whatever?

There must be a better way than just adding more lights until it seems right.

Hi Graeme
In part your problem observation is related to this chart from Lighting for the 40+ | About Lux


I'll come back and add more later

Originally Posted by fletty

Hi Graeme, the only formulae to calculate light fall off that I have used, relate to point sources of light where the light drop is the inverse square of the distance but I haven’t yet seen any formulae for plate sources such as LED panels, so I am now very clearly in the suck-it-and-see camp too! It is nice now that I am fully retired and, for some reason, no longer expected to review, calculate nor justify anything I do?
However, 2 problems I now have are

• A mix of warm and daylight LED panels which will soon be fixed AND
• A currently ongoing mix of fluoro and LED which I mostly notice when photographing in the shed

My next (unjustified, uncalculated) change will be to simply replace the fluoros with daylight LED tubes. Job done

Thanks Fletty

What are the problems, presumably beyond aesthetics, of mixing:

1. warm and daylight LED's, and
2. LED's and fluoros.

I also found the inverse square rule, but it relates only to a single light source. With multiple ceiling lights presumably there is some sort of aggregation of the light waves?????

As I have 3 m high ceilings in the shed, the question boils down to How many light fittings at waht spacing do I need to achieve reasonably level 1,000 lumens at bench height?

A supplementary question might be - should I consider lowering the height of the lights to, say, 2.4 m ???

We seem to be on the same path; add more lights and say WOW, then the next year you start thinking "I need more lights". Time to use science or engineering, not guess
work!


Cheers

Graeme

Originally Posted by BobL

There are a couple of on-line apps that will work it out for you - can't remember where they are are or even the search terms I used to find them. If I remember I will post.

Thanks Bob

My googling only found stuff for calculating attenuation of a single point light, without aggregation.

I thought it would be an easy search - designers of commercial premises must do these calculations repeatedly - specified level of lighting for minimal capital plus electricity costs. But I found nothing, not even the jargon.

Ian is also searching or wracking the old grey cells.



Fair Winds

Graeme

Originally Posted by GraemeCook

should I consider lowering the height of the lights to, say, 2.4 m ???

That will certainly help Graeme. Bringing them down from 3m to 1.5m would make them 4x the brightness at floor level. If your bench is ~0.9m high then lights at 2.4m means they are ~1/3 the distance closer to the bench (from 2.1m down to 1.3m away from the bench).

I'm thinking that will make them 2.6x brighter (2.1*2.1/1.3/1.3 = 2.6)

Originally Posted by FenceFurniture

That will certainly help Graeme. Bringing them down from 3m to 1.5m would make them 4x the brightness at floor level. ......

Or twelve times the brightness at bench height, But I am not vertically challenged and don't want to hit my head on lights at 1.5m !

If your bench is ~0.9m high then lights at 2.4m means they are ~1/3 the distance closer to the bench (from 2.1m down to 1.3m away from the bench).

I'm thinking that will make them 2.6x brighter (2.1*2.1/1.3/1.3 = 2.6)

I think your calculations are accurate, FF, but the question is ... how many light fittings do I need? We want to engineer a solution, not guestimate.



Cheers

Graeme

Originally Posted by GraemeCook

Thanks Fletty

What are the problems, presumably beyond aesthetics, of mixing:

1. warm and daylight LED's, and
2. LED's and fluoros.

Dont underestimate “aesthetics”. I once made a cabinet that, in the owner’s lighting, was far too red. What I think happened was that under my greenish fluoro lighting, the red LOOKED ‘brown’ but, in the owner’s lighting, it was RED! This also gave me the solution though. I gave it a final coat of slightly green tinted WOP ...... and problem solved.
I am now heading towards all ‘daylight’ LEDs