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12 Volt LED lighting.

Dylan

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Dylan Community Regular

Dylan

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I have considered going over to 12V dc LED lighting, but have been put off by the information on the following website. They claim that 13.5 V is the absolute max for these lamps, and I see up to 14.6V (which the current 12V halogens don't seem to enjoy). I wonder if anybody has LED lamps fitted and any experience of their longevity, particularly when battery charging.

 

http://www.reuk.co.uk/Transformers-for-12V-LED-Lighting.htm

 

Quote "LED spotlights are sensitive to voltage, with 13 to 13.5V being the typical absolute maximum useable before permanent damage to the bulbs occurs."

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chris w Veteran II

chris w

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I have considered going over to 12V dc LED lighting, but have been put off by the information on the following website. They claim that 13.5 V is the absolute max for these lamps, and I see up to 14.6V (which the current 12V halogens don't seem to enjoy). I wonder if anybody has LED lamps fitted and any experience of their longevity, particularly when battery charging.

 

http://www.reuk.co.uk/Transformers-for-12V-LED-Lighting.htm

 

Quote "LED spotlights are sensitive to voltage, with 13 to 13.5V being the typical absolute maximum useable before permanent damage to the bulbs occurs."

 

I run a few LED lights and have had no problem with voltage which also goes up to 14.8v when charging. Mine incorporate a voltage regulator and are polarity insensitive as well.

 

Chris

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Dylan Community Regular

Dylan

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I run a few LED lights and have had no problem with voltage which also goes up to 14.8v when charging. Mine incorporate a voltage regulator and are polarity insensitive as well.

 

Chris

Sounds like what I am in need of. Do you know any suppliers of same?

Thanks

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chris w Veteran II

chris w

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Hi Guys

 

Very tempting because of low consumption, but I've always thought they seem a very cold light indeed -- very much the blue end of the spectrum. Have you come across any that are warmer ?

 

Mike.

 

I have "warm white" versions from the above website and they are not blue at all. They are yellowish.

 

Chris

 

PS: just as an interesting aside (at least I hope it is). We all describe bluish light as being cold and a reddish light as being warm. Technically speaking though, it's the other way round. The blue end of the spectrum has a much higher colour temperature (~16,000degK) than the red end (~1600degK). So actually, from the physics point-of-view, red light is cold and blue light is warm :D

Edited by chris w
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tomsk Experienced

tomsk

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I have "warm white" versions from the above website and they are not blue at all. They are yellowish.

 

Chris

 

PS: just as an interesting aside (at least I hope it is). We all describe bluish light as being cold and a reddish light as being warm. Technically speaking though, it's the other way round. The blue end of the spectrum has a much higher colour temperature (~16,000degK) than the red end (~1600degK). So actually, from the physics point-of-view, red light is cold and blue light is warm :D

 

 

I concur, we all have much to learn from Chris

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Chris Pink Veteran II

Chris Pink

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Sorry for going off topic, but has anyone else noticed that radio reception is poor when their LEDs are on? I haven't heard Today on Radio 4 since the end of Autumn :D:)

 

No!

 

think you may have some other issue here, I know of no reason for LEDs to give off radio frequency, i have just done an experiment which confirms this.

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PaulG Experienced

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Interesting. Do you happen to know if these are safe up to 15 Volts?

 

No, I don't - the "technical spec" is a bit thin on the ground! But mine have survived so far. From memory, my charging system is set at 14.8 volts. These do have a high enough light output to use as main lighting (i.e. good enough to be able to read a book comfortably), whereas I haven't seen a LED lamp yet that has. It's also the only one I've found with a standard B.C. fitting.

 

If in doubt, 12v regulators are cheap!

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Dylan Community Regular

Dylan

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No, I don't - the "technical spec" is a bit thin on the ground! But mine have survived so far. From memory, my charging system is set at 14.8 volts. These do have a high enough light output to use as main lighting (i.e. good enough to be able to read a book comfortably), whereas I haven't seen a LED lamp yet that has. It's also the only one I've found with a standard B.C. fitting. If in doubt, 12v regulators are cheap!
True enough. Thanks for your info.
Have you seen these?
They are interesting. Will have a proper look.

 

I got an email from Osram tech dept today re. 12V halogen and LED (unregulated) lamps running at 14.6V :

My email asked if I could expect problems with 12V halogen/LCD lamps running at 14.6V

 

Hi ****,

Yes. More so for halogen bulbs. You are overrunning by nearly 21%. A 10% increase in supply voltage will reduce the life of halogen bulbs by nearly 75% If possible use Automotive bulbs which are designed at 13.8V LED bulbs will be affected but because the life is so long you may not notice its short life, if it survives 14.6 Volts initially. Please retain this message when replying. Regards Dhiru Galani Customer Technical Service

 

Now I know why my 12V halogens are a pain! I have heard it said that people have deliberately introduced volt drop to reduce this problem, but have never tried it personally. Looks like I need regulated lamps!

Edited by Dylan
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chris w Veteran II

chris w

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True enough. Thanks for your info.They are interesting. Will have a proper look.

 

I got an email from Osram tech dept today re. 12V halogen and LED (unregulated) lamps running at 14.6V :

My email asked if I could expect problems with 12V halogen/LCD lamps running at 14.6V

 

Hi ****,

Yes. More so for halogen bulbs. You are overrunning by nearly 21%. A 10% increase in supply voltage will reduce the life of halogen bulbs by nearly 75% If possible use Automotive bulbs which are designed at 13.8V LED bulbs will be affected but because the life is so long you may not notice its short life, if it survives 14.6 Volts initially. Please retain this message when replying. Regards Dhiru Galani Customer Technical Service

 

Now I know why my 12V halogens are a pain! I have heard it said that people have deliberately introduced volt drop to reduce this problem, but have never tried it personally. Looks like I need regulated lamps!

 

I think some of what the guy said in his answer is "bolleaux" IMHO. The transformer supplied with domestic 12v halogens is a 13vac rms version as standard. The peak voltage on these transformers (18.3v) is much higher than the 14.8v found on boats.

 

Chris

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Nickhlx Veteran

Nickhlx

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I am 99.9% sure that simple LEDs do not radiate RF energy...

 

However.....

 

if some of these latest LEDs have an integral driver chip e.g. to accomodate a wide input voltage range, then the driver chip may emit some RFI ( radio frequency interference)

 

Nick

Edited by Nickhlx
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chris w Veteran II

chris w

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The voltage regulator used is a simple miniature (SMT) 7812. There is no oscillator associated with the use of these. If you are picking up RFI from the circuit, it's because the circuit design is poor, resulting in instability and is self-oscillating. There is no inherent reason for LEDs, or their driver circuits, to give off RFI. The 7812 regulator needs a 10nF capacitor at its input and output (close to the chip) to prevent any instability.

 

Buy a packet of ferrite beads from Maplin and slip a few on the power leads to the lighting circuit at various points. Or better, try a diferent manufacturer of the LED circuits.

 

Chris

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Dylan Community Regular

Dylan

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I think some of what the guy said in his answer is "bolleaux" IMHO. The transformer supplied with domestic 12v halogens is a 13vac rms version as standard. The peak voltage on these transformers (18.3v) is much higher than the 14.8v found on boats.

 

Chris

I am not going to get locked in an argument about this but can report the following:

 

12V halogen lamps expire on my boat frequently (various makes). Fact.

They tend to expire mainly when the batteries are charging at night (14.6V). Fact.

They rarely (but occasionally) expire when the batteries are not charging. Fact.

 

I have never had halogens running on a mains power supply so can't comment.

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Dylan Community Regular

Dylan

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My boat is exclusively lit with domestic halogens (with the exception of a couple of LEDs) and I haven't ever replaced one yet. It's curious that we have opposite experiences.

 

Chris

Do you live aboard Chris?

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Dylan Community Regular

Dylan

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No - but I'm open to offers :)

:D

I think that's the problem Chris, we hammer the halogens at night whilst the engine/genny (depending on mood) is running. Definitely going to try some type of regulated lamp. Will report back of course.

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