Dylan Posted February 9, 2008 Report Share Posted February 9, 2008 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." Link to comment Share on other sites More sharing options...
chris w Posted February 10, 2008 Report Share Posted February 10, 2008 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 Link to comment Share on other sites More sharing options...
Dylan Posted February 10, 2008 Author Report Share Posted February 10, 2008 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 Link to comment Share on other sites More sharing options...
chris w Posted February 10, 2008 Report Share Posted February 10, 2008 Sounds like what I am in need of. Do you know any suppliers of same?Thanks IIRC they were from http://www.ultraleds.co.uk Chris Link to comment Share on other sites More sharing options...
Dylan Posted February 10, 2008 Author Report Share Posted February 10, 2008 IIRC they were from http://www.ultraleds.co.uk Chris Many thanks Link to comment Share on other sites More sharing options...
onthecut Posted February 11, 2008 Report Share Posted February 11, 2008 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. Link to comment Share on other sites More sharing options...
chris w Posted February 11, 2008 Report Share Posted February 11, 2008 (edited) 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 Edited February 11, 2008 by chris w Link to comment Share on other sites More sharing options...
tomsk Posted February 11, 2008 Report Share Posted February 11, 2008 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 I concur, we all have much to learn from Chris Link to comment Share on other sites More sharing options...
chris w Posted February 11, 2008 Report Share Posted February 11, 2008 I don't care how nice you are to me Tomsk. I'm not going to pay you more than 20 quid a week and that's an end to it. Chris Link to comment Share on other sites More sharing options...
tomsk Posted February 11, 2008 Report Share Posted February 11, 2008 I don't care how nice you are to me Tomsk. I'm not going to pay you more than 20 quid a week and that's an end to it. Chris Link to comment Share on other sites More sharing options...
PaulG Posted February 11, 2008 Report Share Posted February 11, 2008 Not LED, but higher light output. I've just fitted some of these, and they work well. The only drawback that I can see is that large size of the lamp. 12 volt fluorescent Link to comment Share on other sites More sharing options...
Dylan Posted February 11, 2008 Author Report Share Posted February 11, 2008 Not LED, but higher light output. I've just fitted some of these, and they work well. The only drawback that I can see is that large size of the lamp. 12 volt fluorescent Interesting. Do you happen to know if these are safe up to 15 Volts? Link to comment Share on other sites More sharing options...
AjW Posted February 12, 2008 Report Share Posted February 12, 2008 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 Link to comment Share on other sites More sharing options...
Chris Pink Posted February 12, 2008 Report Share Posted February 12, 2008 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 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. Link to comment Share on other sites More sharing options...
PaulG Posted February 12, 2008 Report Share Posted February 12, 2008 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! Link to comment Share on other sites More sharing options...
Tomska Posted February 12, 2008 Report Share Posted February 12, 2008 Interesting. Do you happen to know if these are safe up to 15 Volts? Have you seen these? Link to comment Share on other sites More sharing options...
Dylan Posted February 12, 2008 Author Report Share Posted February 12, 2008 (edited) 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 February 12, 2008 by Dylan Link to comment Share on other sites More sharing options...
chris w Posted February 12, 2008 Report Share Posted February 12, 2008 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 Link to comment Share on other sites More sharing options...
Nickhlx Posted February 12, 2008 Report Share Posted February 12, 2008 (edited) 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 February 12, 2008 by Nickhlx Link to comment Share on other sites More sharing options...
chris w Posted February 12, 2008 Report Share Posted February 12, 2008 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 Link to comment Share on other sites More sharing options...
Dylan Posted February 12, 2008 Author Report Share Posted February 12, 2008 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. Link to comment Share on other sites More sharing options...
chris w Posted February 12, 2008 Report Share Posted February 12, 2008 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 Link to comment Share on other sites More sharing options...
Dylan Posted February 12, 2008 Author Report Share Posted February 12, 2008 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? Link to comment Share on other sites More sharing options...
chris w Posted February 12, 2008 Report Share Posted February 12, 2008 Do you live aboard Chris? No - but I'm open to offers Link to comment Share on other sites More sharing options...
Dylan Posted February 12, 2008 Author Report Share Posted February 12, 2008 No - but I'm open to offers 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. Link to comment Share on other sites More sharing options...
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