L.E.D Bulbs, deabte . . . - Page 2

briggie · 10-10-2012, 17:05

you have pm plank

rustic · 10-10-2012, 17:06

On my boat I converted the navigation lights to LED, they were originally 10 watts each, so less than an amp.

When I fitted LED's the power consumption dropped to 10 % of the original power..

I will find a note later and post it on the effect of putting 2 led's in series.

One string of LED's in series will take approx 20 mA 0.02 Amps.
Most LED bulbs are wired in series parallel so often have say 8 strings of 2 LED's

So current will be 8x 20 mA or 160 mA or 0.16 amps.

If that helps for now.

(RIP) PLANK · 10-10-2012, 17:07

so, in transposing that equation if V = 12 and I = 10 then P = 120

so if a light is giving off 120 watts at 12 volts it must be drawing 10 amps regardless of it's filament or LED status.

In this case the 'missing' power is used by the resistors that are allowing the LED's to run at 12 volts.

even if one considers that LEDs of much lower wattage are used to produce the same quality of light (lumens/kelvins?) then by default some power must be being wasted by running LED's at 12v

I have ordered 10 Led "bulbs" and will do some measuring when they arrive, though they are on a slow boat from China so I won't hold my breath

briggie · 10-10-2012, 17:09

the pm i sent you explains it plank , if you dont fall asleep reading it

briggie · 10-10-2012, 17:22

i love a good debate , im often called a great mass debator ...... or i think thats what they said

(RIP) PLANK · 10-10-2012, 17:56

I have had a skim through it, but the mainstay of the power consumption charts seem to be relating to LED's at their optimum operating voltage, the power loss from and additional components needed to convert another voltage , 12v for example, to the ideal LED operating voltage still seems to be another issue and must use more power!

Another interesting thin I have found by reading the listings of ebay LED vehicle bulbs, very few make any mention of the power consumption or give any figures, it just seems 'assumed' that consumption will be lower. As it would be if you replaced a 4v filament bulb for a 4v LED, In a vehicle application this makes little difference and there are other benefits to LEDs but if lowering power consumption is your aim then maybe LED bulbs aren't all they are assumed to be

Moochin · 10-10-2012, 18:27

18 years ago I completed a National Diploma in Electronics, I have just read through this and decided I haven't the first clue how I managed to pass.

96terrano · 10-10-2012, 18:28

Quote:

Originally Posted by Moochin

18 years ago I completed a National Diploma in Electronics, I have just read through this and decided I haven't the first clue how I managed to pass.

(RIP) PLANK · 10-10-2012, 19:48

you would love the stuff me an Briggie have been going through then! A nice university research paper on LED's with load of equations. We are both ex tv engineers, from when they were big and heavy and made of glass and videos had tapes that top loaded

briggie · 10-10-2012, 19:57

memories plank ?

http://sxemi.net/tvs%20Philips2.htm

briggie · 10-10-2012, 19:59

oh the fun of shorting the final athode to the chassis ..... those where the days

(RIP) PLANK · 10-10-2012, 20:07

I gave myself a shock doing that once! my hair stood on end and my tie straight out at 90% in front of me! And i burnt two small holes in my finger right down to the bone

solarman216 · 10-10-2012, 20:28

when I was a kid, my dad was always bringing old TV sets home to try and repair, needless to say most got bunged in my direction to pull to bits, I found the quickest way to kill earth worms was the spark from the final anode, what fun we had then, could you see that today, Rick

(RIP) PLANK · 10-10-2012, 20:33

I don't think plasma screens are quite as lethal

(RIP) PLANK · 10-10-2012, 20:34

Rustic - for some reason the quote button isn't working but cheers for that! As i really need to drop my power consumption now the nights are drawing in

10-10-2012, 17:06	#17
rustic Senior Member Join Date: Feb 2007 Location: Staffordshire Vehicle: Maverick Mk I 2.7 TD LWB Posts: 7,825	On my boat I converted the navigation lights to LED, they were originally 10 watts each, so less than an amp. When I fitted LED's the power consumption dropped to 10 % of the original power.. I will find a note later and post it on the effect of putting 2 led's in series. One string of LED's in series will take approx 20 mA 0.02 Amps. Most LED bulbs are wired in series parallel so often have say 8 strings of 2 LED's So current will be 8x 20 mA or 160 mA or 0.16 amps. If that helps for now. __________________ Ford Maverick GLX 1995 2.7TD LWB in illusion silver, 98k miles. Owned since new, for 22 years. Best car I have ever owned. Just wish I could drive it more.

10-10-2012, 20:28	#28
solarman216 Off road maniac Join Date: Dec 2009 Location: Bexhill on Sea Vehicle: Y60 Patrol Me, 3 ltr Mrs Posts: 17,428	when I was a kid, my dad was always bringing old TV sets home to try and repair, needless to say most got bunged in my direction to pull to bits, I found the quickest way to kill earth worms was the spark from the final anode, what fun we had then, could you see that today, Rick __________________ Ex banger racer now off road maniac Lokka on the front with manual hubs Diff lock on rear 3 inch SS straight through exhaust Manly winch bumper with 13000 lb winch 10 spike ground anchor, with multiple straps and blocks Super strong body cills capped with scaffold pole 20% stronger springs all round aggressive off road tyres on wheels so just swap. Aim to get stuck and be completely self sufficient in extraction, love getting muddy, 2ft deep is good but rare.

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10-10-2012, 17:05	#16
briggie Senior Member Join Date: Mar 2010 Location: peoples democratic republic of west yorkshire Vehicle: " alice " Posts: 10,473	you have pm plank

10-10-2012, 17:07	#18
(RIP) PLANK Senior Member Join Date: Mar 2006 Location: Central England, in the Heart of the Black Country Vehicle: T2 2004 TDI SE LWB Posts: 7,740	so, in transposing that equation if V = 12 and I = 10 then P = 120 so if a light is giving off 120 watts at 12 volts it must be drawing 10 amps regardless of it's filament or LED status. In this case the 'missing' power is used by the resistors that are allowing the LED's to run at 12 volts. even if one considers that LEDs of much lower wattage are used to produce the same quality of light (lumens/kelvins?) then by default some power must be being wasted by running LED's at 12v I have ordered 10 Led "bulbs" and will do some measuring when they arrive, though they are on a slow boat from China so I won't hold my breath

10-10-2012, 17:09	#19
briggie Senior Member Join Date: Mar 2010 Location: peoples democratic republic of west yorkshire Vehicle: " alice " Posts: 10,473	the pm i sent you explains it plank , if you dont fall asleep reading it

10-10-2012, 17:22	#20
briggie Senior Member Join Date: Mar 2010 Location: peoples democratic republic of west yorkshire Vehicle: " alice " Posts: 10,473	i love a good debate , im often called a great mass debator ...... or i think thats what they said

10-10-2012, 17:56	#21
(RIP) PLANK Senior Member Join Date: Mar 2006 Location: Central England, in the Heart of the Black Country Vehicle: T2 2004 TDI SE LWB Posts: 7,740	I have had a skim through it, but the mainstay of the power consumption charts seem to be relating to LED's at their optimum operating voltage, the power loss from and additional components needed to convert another voltage , 12v for example, to the ideal LED operating voltage still seems to be another issue and must use more power! Another interesting thin I have found by reading the listings of ebay LED vehicle bulbs, very few make any mention of the power consumption or give any figures, it just seems 'assumed' that consumption will be lower. As it would be if you replaced a 4v filament bulb for a 4v LED, In a vehicle application this makes little difference and there are other benefits to LEDs but if lowering power consumption is your aim then maybe LED bulbs aren't all they are assumed to be

10-10-2012, 18:27	#22
Moochin Junior Member Join Date: Oct 2012 Location: Staffordshire Vehicle: 1999 Terrano 2.7 Tdi Posts: 12	18 years ago I completed a National Diploma in Electronics, I have just read through this and decided I haven't the first clue how I managed to pass.

10-10-2012, 19:48	#24
(RIP) PLANK Senior Member Join Date: Mar 2006 Location: Central England, in the Heart of the Black Country Vehicle: T2 2004 TDI SE LWB Posts: 7,740	you would love the stuff me an Briggie have been going through then! A nice university research paper on LED's with load of equations. We are both ex tv engineers, from when they were big and heavy and made of glass and videos had tapes that top loaded

10-10-2012, 19:57	#25
briggie Senior Member Join Date: Mar 2010 Location: peoples democratic republic of west yorkshire Vehicle: " alice " Posts: 10,473	memories plank ? http://sxemi.net/tvs%20Philips2.htm

10-10-2012, 19:59	#26
briggie Senior Member Join Date: Mar 2010 Location: peoples democratic republic of west yorkshire Vehicle: " alice " Posts: 10,473	oh the fun of shorting the final athode to the chassis ..... those where the days

10-10-2012, 20:07	#27
(RIP) PLANK Senior Member Join Date: Mar 2006 Location: Central England, in the Heart of the Black Country Vehicle: T2 2004 TDI SE LWB Posts: 7,740	I gave myself a shock doing that once! my hair stood on end and my tie straight out at 90% in front of me! And i burnt two small holes in my finger right down to the bone

10-10-2012, 20:33	#29
(RIP) PLANK Senior Member Join Date: Mar 2006 Location: Central England, in the Heart of the Black Country Vehicle: T2 2004 TDI SE LWB Posts: 7,740	I don't think plasma screens are quite as lethal

10-10-2012, 20:34	#30
(RIP) PLANK Senior Member Join Date: Mar 2006 Location: Central England, in the Heart of the Black Country Vehicle: T2 2004 TDI SE LWB Posts: 7,740	Rustic - for some reason the quote button isn't working but cheers for that! As i really need to drop my power consumption now the nights are drawing in