LED Household lighting

[rovers1952]

GU10 LED's finally getting cheaper. Bought 4 from Ikea Rhodes @ $14.99 ea.
specs...4watt, 125lm. 3000kelvin, 38 degree single beam, 20,000 hrs. The chrome shroud on original fitting even fits snugly on new LED. Have installed the 4 over kitchen island bench. Not at bright as original 35watt halogens but acceptable.
Will wait for the three spot 9 watt variety to get cheaper before replacing the remaining 6 over the kitchen work area.

[bee utey]

There are huge numbers of LED downlights on ebay, I have bought bunches of 9W ones for varoius people, and they have been great so far. These might be up your alley:

6 x GU10 9W 3x3w DIMMABLE LED DOWNLIGHT COLD WHITE 240V (eBay item 250784690517 end time 10-Mar-11 13:22:06 AEDST) : Home (http://cgi.ebay.com.au/6-x-GU10-9W-3x3w-DIMMABLE-LED-DOWNLIGHT-COLD-WHITE-240V-/250784690517?pt=AU_Lighting_Fans&hash=item3a63eeb155)

[101RRS]

Are there LED globes that can replace current low voltage halogen globes??

Or do you need to replace the entire fitting.

Garry

[d2dave]

There are huge numbers of LED downlights on ebay, I have bought bunches of 9W ones for varoius people, and they have been great so far. These might be up your alley:

6 x GU10 9W 3x3w DIMMABLE LED DOWNLIGHT COLD WHITE 240V (eBay item 250784690517 end time 10-Mar-11 13:22:06 AEDST) : Home (http://cgi.ebay.com.au/6-x-GU10-9W-3x3w-DIMMABLE-LED-DOWNLIGHT-COLD-WHITE-240V-/250784690517?pt=AU_Lighting_Fans&hash=item3a63eeb155)

I have a question. If I get 3 25w incandesant globes and put them together am I going to get the same light as one 75w globe. I would have thought not but I could be wrong.

However if I am right this would mean that the above globe would use 9w of power but only produce a larger amount of 3w light.

Anyone able to answer this.

Dave.

[bee utey]

Are there LED globes that can replace current low voltage halogen globes??

Or do you need to replace the entire fitting.

Garry
Most of the 9W led lamps I bought were the 12V MR16 style designed as a drop-in fitment for 12V halogens. I have been wiring mine to a solar charged 12V system to save electrician's costs. They appear on ebay for $20 to $40 each, depending on who just imported a gross of them.

These are mid-range priced ones from a good seller:

6X 9W MR16 3x3w XR-E 12V CREE LED DOWNLIGHT GLOBES (eBay item 320593958630 end time 21-Mar-11 19:37:46 AEDST) : Home (http://cgi.ebay.com.au/6X-9W-MR16-3x3w-XR-E-12V-CREE-LED-DOWNLIGHT-GLOBES-/320593958630?pt=AU_Lighting_Fans&hash=item4aa4e396e6)

[bee utey]

I have a question. If I get 3 25w incandesant globes and put them together am I going to get the same light as one 75w globe. I would have thought not but I could be wrong.

However if I am right this would mean that the above globe would use 9w of power but only produce a larger amount of 3w light.

Anyone able to answer this.

Dave.

Globes are rated in watts of power consumption, ie their input. Light output is rated in lumens. LED lamps are something like 5 times as efficient as tungsten filament globes at producing light, so a 9W LED is close to a 40W globe in output. Same as compact fluoro globes but they go to full output instantly when turned on. And they don't get very hot so can't start fires like the halogen lamps.

[rovers1952]

Thanks Bee Utey...had a look...getting closer now. Will get cheaper but a finite market because the lamps last virtually a lifetime....

garrycol...yes they are retro fit...just replace old globes...

and mr Whippy...I am hoping that the the 3 x 3 watt in the single globe delivers three times my single spot 3w globe....and something close the old halogen 35 - 50 watt GU10.

These lamps over time will put the power companies out of business!!!!

[d2dave]

Globes are rated in watts of power consumption, ie their input. Light output is rated in lumens. LED lamps are something like 5 times as efficient as tungsten filament globes at producing light, so a 9W LED is close to a 40W globe in output. Same as compact fluoro globes but they go to full output instantly when turned on. And they don't get very hot so can't start fires like the halogen lamps.

I do understand this but does not answer my question.

I will put it this way. Is an LED globe with three x three watt globes as bright as one nine watt LED

Dave.

[101RRS]

Yes - three globes are brighter than one, but not three times brighter - but don't ask me why?.

[bee utey]

I do understand this but does not answer my question.

I will put it this way. Is an LED globe with three x three watt globes as bright as one nine watt LED

Dave.
Oh, yes, so long as you are comparing similar chips. Cree XR-E 3W chips are amongst the best currently available. Technology changes all the time so improvements will make earlier types obsolete. Currently the 10W MC-E single chip lights are around $60 and have 500 lumen output compared to 400 lumen for the 3x3W ones.

[Lionel]

Most of the 9W led lamps I bought were the 12V MR16 style designed as a drop-in fitment for 12V halogens. I have been wiring mine to a solar charged 12V system to save electrician's costs. They appear on ebay for $20 to $40 each, depending on who just imported a gross of them.

These are mid-range priced ones from a good seller:

6X 9W MR16 3x3w XR-E 12V CREE LED DOWNLIGHT GLOBES (eBay item 320593958630 end time 21-Mar-11 19:37:46 AEDST) : Home (http://cgi.ebay.com.au/6X-9W-MR16-3x3w-XR-E-12V-CREE-LED-DOWNLIGHT-GLOBES-/320593958630?pt=AU_Lighting_Fans&hash=item4aa4e396e6)

The 12V version need to be used with the correct transformer. Older style iron cores are fine, but the solid state (switchmode) ones are no good for LED's. The best is a proper LED driver but more $$$.

No problem if you have a solar 12V DC setup.

Cheers,

Lionel

[austastar]

Yes - three globes are brighter than one, but not three times brighter - but don't ask me why?.

Hi,
inverse square law.

From a point source the light diminishes by the inverse square of the distance.
i.e. 2x distance and the light is 1/4, 3x distance and the light is 1/9

With multiple light sources you are making the source larger and effectively reducing the distance some what.

here endeth the lesson

cheers

[101RRS]

I don't think so - you are correct if distances vary but if they are the same - essential a single light source you have then not answered the question why three times the globes is not three time brighter. :)

[bee utey]

I don't think so - you are correct if distances vary but if they are the same - essential a single light source you have then not answered the question why three times the globes is not three time brighter. :)

Some multi-chip lights are de-rated because of heat build up. But the 3x3W lamp chips are a good 15mm apart so this is not an effect here. The inverse square thingy would apply at distances comparable to the chip separation but not at metre-sized distances. And of course brightness isn't the same as light output as it depends on the lamps designed viewing angle, as in the lenses supplied with the light. The 3x3W lights I have been using were 60 degree units. I found the light too concentrated for general illumination so I removed the lenses (collimators) and they have a 160 drgreee spread instead.

[Mudsloth]

I bought 5 14 watt leds off ebay for 20 bucks i think it was about a year ago, i have three in my lounge room and a couple in the shed that run off batteries and they work great. They have a little way to go but I'm happy.

[brad72]

For good lights in your tent etc check out the LED strip lights. You can get the in 1 meter lengths and waterproof. Being 12v you just hook up to your battery.

I build LED mountain biking and portable lighting and use the latest Cree XPG and XML led's and use constant current boost and buck drivers. These enable me to either produce higher voltages than the input source(boost) or lower voltages (buck).

We also drive our leds with constant current drivers, not voltage. This means we can accurately drive the output in terms of brightness and battery draw without any dimming as the voltage drops. We usually use 350mA, 750mA ...........3000mA. The other advantage of driving the leds in this way is heat management.

One project I am about to start on is a light bar my D4. I will use 2 parallel strings of 23 series wired Leds wired. To give some idea of the brightness my 3 led mountain bike puts out just under 3000 lumen so 46 leds will produce a wall of light. Even if I drive them @ 700mA I will still get close to 11,500 lumen, pump it up to 2800mA and I'll get a whopping (or ridiculous) 37,000 lumen but will also generate a lot of heat which needs to be shed or the output of the leds will decrease, or worse, kill the leds completely.

Heres a picture of the 3 led light and a beam shot to give some idea of the brightness. This one pumps out about 2700 lumen on full power. The horse is 50 meters away and the houses in the distance are 200 meters way. The 3 leds are series wired are being driven a 2800mA high, 2000mA medium and 1000mA low from a 14.8v li-ion battery drawing about 26 watts on High.

http://img98.imageshack.us/img98/5104/p2120203.jpg

http://img33.imageshack.us/img33/7724/p2120195.jpg

The light below is a 7 led one putting out about 1700-2000 lumen when driven at 1300ma,

http://img811.imageshack.us/img811/2897/pa280117.jpg