Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.

 Prev 1 | ... | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | ... | 47 Next

## switchlighting

18 posts

Geek

Reply # 674953 21-Aug-2012 09:18

Lets assume we want the efficiency from a 3000K light (assume the led die temp is 85 deg C)

Here are the incorrect ways (but most common) in order of how wrong it is.

- 1000 lumen / 10 watts = 100 L/watt (it will say on box "for 5000k led")
- 850 lumen / 10 watts = 85 L/watt
- 1000 lumen / 13 watts = 77 L/watt (it will say on box "for 5000k led")
- 850 lumen / 13 watts = 65 L/watt

(To stay competitive we have also had to published efficiencies based on the above)

The correct way is as follows:

(750 x .9 x .91) /13 = 47L/watt

The best way is to have the light output measured by a integrating sphere to calculate the output lumen.

In practise it is not easy to make a focused dimming light with an efficiency over 60 - 65 L/watt

## timmmay

13079 posts

Uber Geek
+1 received by user: 2157

Trusted
Subscriber

Reply # 674962 21-Aug-2012 09:24

switchlighting:
The correct way is as follows:

(750 x .9 x .91) /13 = 47L/watt

Assuming 750 is lumens you have two magic numbers in there... what are .9 and .91, and where did you get them from?

AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer

## switchlighting

18 posts

Geek

Reply # 674967 21-Aug-2012 09:31

lens loss = 0.1 so multiply by 0.9
Glass loss = 0.09 so multiply by 0.91

These are approximate real life losses.

## CYaBro

2768 posts

Uber Geek
+1 received by user: 214

Reply # 674974 21-Aug-2012 09:43

timmmay: I think it's these ones, but the Lighting Direct website seems to be down. It's these ones, in white. 11W, 600 lumen, 54 lumen per watt. I wasn't that bothered about absolute efficiency, they're nice looking lights that are bright enough and use less power than most others. If I was putting them through my entire house I may have paid more attention to efficiency, but in the bathroom that's only used an hour a day it doesn't matter.

Not bad but the driver is built in to the unit so I wouldn't have chosen them.
They also don't say if they are dimmable or not, so I would assume not, which is a feature that I wanted.
It also doesn't say what brand of LED they have in them.

## timmmay

13079 posts

Uber Geek
+1 received by user: 2157

Trusted
Subscriber

Reply # 674979 21-Aug-2012 09:46

CYaBro:
timmmay: I think it's these ones, but the Lighting Direct website seems to be down. It's these ones, in white. 11W, 600 lumen, 54 lumen per watt. I wasn't that bothered about absolute efficiency, they're nice looking lights that are bright enough and use less power than most others. If I was putting them through my entire house I may have paid more attention to efficiency, but in the bathroom that's only used an hour a day it doesn't matter.

Not bad but the driver is built in to the unit so I wouldn't have chosen them.
They also don't say if they are dimmable or not, so I would assume not, which is a feature that I wanted.

Not dimmable, apparently the dimmable model is out soon.

The driver's not inside the light, there's a cord between them. I doubt you can replace it if it breaks, but honestly at \$80 the lights are so cheap that if they fail after 5 years I just replace the whole unit.

AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer

## CYaBro

2768 posts

Uber Geek
+1 received by user: 214

Reply # 674985 21-Aug-2012 09:47

timmmay:
CYaBro:
timmmay: I think it's these ones, but the Lighting Direct website seems to be down. It's these ones, in white. 11W, 600 lumen, 54 lumen per watt. I wasn't that bothered about absolute efficiency, they're nice looking lights that are bright enough and use less power than most others. If I was putting them through my entire house I may have paid more attention to efficiency, but in the bathroom that's only used an hour a day it doesn't matter.

Not bad but the driver is built in to the unit so I wouldn't have chosen them.
They also don't say if they are dimmable or not, so I would assume not, which is a feature that I wanted.

Not dimmable, apparently the dimmable model is out soon.

The driver's not inside the light, there's a cord between them. I doubt you can replace it if it breaks, but honestly at \$80 the lights are so cheap that if they fail after 5 years I just replace the whole unit.
g

Bugger!  Your link is working now and the price is only \$67.90 at the moment. :D

## richms

20180 posts

Uber Geek
+1 received by user: 3782

Trusted
Subscriber

Reply # 675037 21-Aug-2012 11:38

CYaBro:

Bugger!  Your link is working now and the price is only \$67.90 at the moment. :D

I can only find 3000k on lighting direct. At that price if they do 4000k or better then it becomes a no brainer to install them, so long as the beam spread is acceptable for in home use.

Richard rich.ms

## Skolink

1028 posts

Uber Geek
+1 received by user: 13

Reply # 675058 21-Aug-2012 12:24

switchlighting, will the new EECA / Energy Star luminaire labelling standards address the inconsistancies with claimed light output and efficiencies. All I am aware of is the CFLs will now have to be labelled with light output (in lumens).

## timmmay

13079 posts

Uber Geek
+1 received by user: 2157

Trusted
Subscriber

Reply # 675062 21-Aug-2012 12:29

richms:
CYaBro:

Bugger!  Your link is working now and the price is only \$67.90 at the moment. :D

I can only find 3000k on lighting direct. At that price if they do 4000k or better then it becomes a no brainer to install them, so long as the beam spread is acceptable for in home use.

I can't remember what I got, and they're not installed yet. From memory I got one that's neither a cool white nor a warm white, a nice balance.

It has a beam spread of around 90 degrees, with a translucent diffuser, so it's pretty good. I had one working in my hand, it's really pretty bright.

AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer

## richms

20180 posts

Uber Geek
+1 received by user: 3782

Trusted
Subscriber

Reply # 675065 21-Aug-2012 12:32

Ok, will be interesting to see how they go.

I am very happy with the 7w viribrights in normal downlights around the house so would only be considering these for the bath areas, would want the same colour as the rest of the house.

If the price approches the price of a viribright in a cheapish recessed E27 GLS fitting then I might opt for them in other places too, but really I think just kitchen and bathroom need the IP fittings.

Richard rich.ms

## CYaBro

2768 posts

Uber Geek
+1 received by user: 214

Reply # 675474 22-Aug-2012 13:36

Lights arrived this morning.
Just wired one up temporarily on the workbench at work and almost blinded myself!
Not a good idea to be looking directly at the LED when you turn it on. :)

## timmmay

13079 posts

Uber Geek
+1 received by user: 2157

Trusted
Subscriber

Reply # 675477 22-Aug-2012 13:45

I had the same experience with my LEDs, super bright... just like any light bulb really.

AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer

## richms

20180 posts

Uber Geek
+1 received by user: 3782

Trusted
Subscriber

Reply # 675491 22-Aug-2012 14:22

Ive just got my 10W bare LEDs on a heatsink from ebay that I am going to be putting in the aquarium, cant recall if I got the 10000k or 12000k now, but till my drivers arrive I cant really see how they go.

Richard rich.ms

## switchlighting

18 posts

Geek

Reply # 675808 23-Aug-2012 09:21

Hello Skolink,

Interesting question.... Only lights that pass the rigorous energy star testing will have to display any of the energy star required markings. I have had a quick look through the energy star tests and packaging but cannot find a requirement to mark with lumen output.... not sayings it not their though as the document is 40 pages long. I would imagine if it is energy star then it should be correct though.

Cheers.

## networkn

14448 posts

Uber Geek
+1 received by user: 3574

Trusted
Subscriber

Reply # 678854 29-Aug-2012 17:16

Do you think it would be reasonable to use LED lighting in a kitchen?

http://www.houzz.com/photos/kitchen-lighting-and-cabinet-lighting/

 Prev 1 | ... | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | ... | 47 Next

Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

News »

Symantec protects data everywhere with Information Centric Security
Posted 21-Sep-2017 15:33

FUJIFILM introduces X-E3 mirrorless camera with wireless connectivity
Posted 18-Sep-2017 13:53

Vodafone announces new plans with bigger data bundles
Posted 15-Sep-2017 10:51

Skinny launches phone with support for te reo Maori
Posted 14-Sep-2017 08:39

If Vodafone dropping mail worries you, you’re doing online wrong
Posted 11-Sep-2017 13:54

Vodafone New Zealand deploy live 400 gigabit system
Posted 11-Sep-2017 11:07

OPPO camera phones now available at PB Tech
Posted 11-Sep-2017 09:56

Norton Wi-Fi Privacy — Easy, flawed VPN
Posted 11-Sep-2017 09:48

Lenovo reveals new ThinkPad A Series
Posted 8-Sep-2017 14:37

Huawei passes Apple for the first time to capture the second spot globally
Posted 8-Sep-2017 10:45

Vodafone initiative enhances te reo Maori pronunciation on Google Maps
Posted 8-Sep-2017 10:40

Voyager Internet expand local internet phone services company with Conversant acquisition
Posted 6-Sep-2017 18:27

NOW Expands in to Tauranga
Posted 5-Sep-2017 18:16

Windows 10 Fall Creators Update coming Oct. 17
Posted 4-Sep-2017 14:10

Garmin introduce Garmin vivoactive 3
Posted 1-Sep-2017 18:38

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.

©2002-2017 Geekzone®