Overhead lamps and heat

jviss

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Hi MS,

I have seven Scandvik "traditional" dome ceiling fixtures in the over head and under cabinets in my 1996 Tartan 3800.


They have LEDs in them now, 15 SMD cylindrical units, with two pins. It appears they were originally fitted with halogen bulbs, and though there's a vague reference in the current catalog to 20W halogens, I can't be sure what was originally fitted.

I like these disc-type, side pin LED equivalents.

If the original was xenon or halogen, presumably at higher wattage than the equivalent brightness LED, could LEDs possibly have a heat problem in a sealed lamp? Maybe not a fire hazard, but perhaps a life problem for the LED module itself?

Thanks,

jv
 
Rick D

Rick D

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Jun 14, 2008
7,138
Hunter Legend 40.5 Shoreline Marina Long Beach CA
I have had my LED bulbs in closed lamps on the boat for about ten years. No issues. They replaced halogen.
 
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Benny17441

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May 24, 2004
7,131
CC 30 South Florida
Some of these LED's do generate heat and it seems to happen more with those plug in adapted units and much less with integrated light fixtures. I don't know if some design features are responsible but yes that has been my experience, some do get pretty warm. Would think the design would recognize the presence of heat and incorporate a safeguard to preserve the module's life. Google it.
 
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Benny17441

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May 24, 2004
7,131
CC 30 South Florida
I just read some on it and came to the realization that all LED's do generate heat but not infrared heat like incandescent bulbs. LED's output is reported as 15% light and 85% heat; thermal management circuitry is what controls their heat. High power LED's generate more heat than regulars. Came to the conclusion that cheaper lights may not have as an efficient thermal management as the more expensive ones. I just skimmed an article so I'm sure there is more to it than what I gathered.
 
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dlochner

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Jan 11, 2014
11,401
Sabre 362 113 Fair Haven, NY
Benny17441 said:
I just read some on it and came to the realization that all LED's do generate heat but not infrared heat like incandescent bulbs. LED's output is reported as 15% light and 85% heat; thermal management circuitry is what controls their heat. High power LED's generate more heat than regulars. Came to the conclusion that cheaper lights may not have as an efficient thermal management as the more expensive ones. I just skimmed an article so I'm sure there is more to it than what I gathered.
Click to expand
The ratio of heat to light on LED bulbs is similar to halogen and incandescent bulbs. However, the amount of light given off per watt is much greater for LEDs. If a 1 watt LED gives off the same amount of light as a 20 watt Halogen and the ratio of heat to light is the same, then the LED gives off .85 watts of heat energy and the Halogen gives off 17 watts of heat energy for the same amount of light, the halogen gives off 20 times the heat the LED does.

Note, the actual heat to light ratios may be a little different, but the point remains the same, the LEDs use less energy overall, so the amount lost to heat will be less than with incandescent and halogen bulbs.
 
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ClaudioSalles

ClaudioSalles

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Mar 4, 2015
1
Beneteau M510 Ubatuba - Sao Paulo
I replaced all halogen bulbs from my Beneteau M510 with 9 warm white 5050 LEDs like below, and I'm very happy:
9 LEDs.jpg
 

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kloudie1

kloudie1

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Nov 6, 2006
9,892
Hunter 34 Mandeville Louisiana
Converted everything in the cabin to disk/side pin and festoon types, 8/9 years ago and have been happy with them. much less heat than the old incandescents and halogens.. They are warm to the touch but not hot like the old ones.. No failures to date. Still have a very bright fluorescent over the sink .. haven't found a suitable LED yet.
 
jssailem

jssailem

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Oct 22, 2014
21,088
CAL 35 Cruiser #21 moored EVERETT WA
I converted to a red/warm white flood in the over the table and a warm white over the sink. Thinking of changing both to red/warm white.
Would not go back. They are not generating heat. And the light is excellent. Less glare than before with the incandescent bulbs.
 
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Benny17441

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May 24, 2004
7,131
CC 30 South Florida
There was something about incandescent lights putting out 5% of light, 85% of IR heat and 10% of transferred heat vs LEDs putting out 15% of light and 85% of transferred and 0% of IR heat. It would seem that the lightbulb sockets in the old fixtures were designed to handle the 10% of transferred heat and not the 85% transferred by LEDs. Granted the reduced power consumption of LEDs help compensate for the differences in actual transferred heat. This might help explain why the newer integrated LED fixtures do run cooler than those lights adapted for use in traditional sockets. I guess a good test would be to measure the temperature of the socket after burning an incandescent light and the temperature of the same socket after burning an LED light. Nevertheless LED's are the future, more efficient and a great upgrade for boats. As for the question if some sockets could pose a fire hazard I would say check the actual temperature and the materials around it. IR heats transfers by light to a surface while transferred heat moves by contact in heating the air to the surface.
 
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SEMPERAVANTI41

SEMPERAVANTI41

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Jun 15, 2012
695
BAVARIA C57 Greenport, NY
Original halogen light bulbs got the fixtures got so hot I thought they would cause the headliner to catch fire. Replaced bulbs with LED's, no more worries.
 
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jviss

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
I measured current today. Incandescent automotive-type bulb, 1.5A. Replacement LED "cluster" bulb, 57mA. That's 1/26th of the current, and therefore power, of the incandescent. Wow.
 
Ken Cross

Ken Cross

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Oct 24, 2010
2,405
Hunter 30 Everett, WA
Now if we could just get the refrigerator to efficiency like that. That's what sucks down our house bank.
Ken
 
jviss

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Ken Cross said:
Now if we could just get the refrigerator to efficiency like that. That's what sucks down our house bank.
Ken
Click to expand
Agreed! One of the issues with mine is that the stock thermostat is so primitive that getting it set to the right point could take a whole season, and meanwhile, it is so easily accidentally changed, we never know what's going on. It ran nearly continuously Friday night because of this, consuming about 60Ah.

I plan on fitting an Inkbird temperature controller.
 
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