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LEDs for RV lighting?

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MikeMl

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I just spent a week in a travel trailer (caravan for some english speakers ;) ). It has a couple of deep-cycle flooded-cell lead-acid batteries for basic electrics like lighting, the water pump, and heating (just the fan, the heat source is Propane). I noticed that it is the lighting that is the biggest part of the battery load.

There are several light fixtures, each of which use 2 ea. 12V 10W lamps, so getting rid of the lamps and replacing them with LEDs would go a long way to extending battery run times. Only a couple of high-usage fixtures would need to be modified.

I'm looking for recommendations on sources and availability of high-output white LEDs suitable for lighting to replace the 10W incandescent lamps. I can deal with the current-limiters, and mechanical modifications of the light fixtures. I am looking for specific LED suppliers and sources.
 

crutschow

Well-Known Member
Most Helpful Member
Certainly there are many suppliers of high-efficiency white LEDs such as smtzone but I have no direct experience with any of them.

Since your are interested in maximum efficiency, you should use a constant-current switching regulator designed to drive the LEDs such as this LM3409 - PFET Buck Controller for High Power LED Drives.
 
It's tough to beat a good 15W fluorescent fixture.

These guys have a lot of led stuff Cutter.

Here's my piss poor attempt at an led lamp. Well it turns out to be a good mood light, that's about it, don't have to burn a candle. It hot spots the lens.
 

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kchriste

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I used to have a trailer that had both 120v and 12V lighting systems. I simply swapped out the 120V incandescents with CFLs and powered the 120V side with an inverter. I did have to turn off the 120V power hogs such as the hot water heater, etc.
If you only have a 12V lighting system, you can get fluorescents which will run on 12V from an RV place. Probably more efficient than LEDs or my inverter method.
 

k7elp60

Active Member
I just spent a week in a travel trailer (caravan for some english speakers ;) ). It has a couple of deep-cycle flooded-cell lead-acid batteries for basic electrics like lighting, the water pump, and heating (just the fan, the heat source is Propane). I noticed that it is the lighting that is the biggest part of the battery load.

There are several light fixtures, each of which use 2 ea. 12V 10W lamps, so getting rid of the lamps and replacing them with LEDs would go a long way to extending battery run times. Only a couple of high-usage fixtures would need to be modified.

I'm looking for recommendations on sources and availability of high-output white LEDs suitable for lighting to replace the 10W incandescent lamps. I can deal with the current-limiters, and mechanical modifications of the light fixtures. I am looking for specific LED suppliers and sources.

Here is a site that has good LEDs
SUPER BRIGHT LEDS home
They have some replacement LED lights for existing 12 bulbs.
The problem I have encountered with the replacement LED's is the intensity and color don't match the incandescent bulbs.

I have had 2 travel trailers and I soon discovered that the incandescent bulbs in them had a fairly high failure rate. I developed a circuit that eliminated the surge current for the bulbs and increased the life many times.

I have PV panels at home to charge a large 12V battery and I use some RV light fixtures with my surge eliminater circuit installed for reading lights. I finally changed a bulb after nearly 10 years of almost daily use.
 

tcmtech

Banned
Most Helpful Member
There are 12 volt CFL's on the market now for around $9 that use the common Edison base style. It could be one way to go as well.
 

Ubergeek63

Well-Known Member
I'm looking for recommendations on sources and availability of high-output white LEDs suitable for lighting to replace the 10W incandescent lamps. I can deal with the current-limiters, and mechanical modifications of the light fixtures. I am looking for specific LED suppliers and sources.
All i can say for that super bright site is GAG, COUGH, SPUTTER..

DealExtreme: $5.50 Rebel LED Emitter on Star (0080 BIN) is a rebel for $5 that will put out about 145Lm at 700mA and is by itself sufficient to replace two of those bulbs (10W @ 7Lm/W is about 140Lm for two bulbs) and a supertex hv9910 will drive it on 12V even though the part can be use off the AC rail levels. (while that is on a star and not the normally supplied part goes for $2 on a 250 pc reel and there is a 180Lm part for $2.76, both Future Electronics distributor prices)

someone else was saying about mini fluorescents but the 12V ones do not get the efficiencies that the bigger ones do, thought that is not well known.

Dan
 

MikeMl

Well-Known Member
Most Helpful Member
Thanks for all the suggestions. This is why I posted the question. I see that the Cree LEDs are available in the US from DigiKey.

Being a Ham, and wanting to operate on HF from the "boonies", I am reluctant to go with CFL's, florescents, or even a switcher-based LED drivers because of the RFI. The HF band here at my house is getting more cluttered with harmonics from switching power supplies all the time; the last thing I want to do is put those infernal devices in my trailer.

I have tried operating from a houseboat that had 12VDC operated small florescent fixtures, and the racket on 3 to 7 MHz due to the step up switchers in the florescent fixtures was incredible. I could even detect other houseboats as they approached from more than 1/4mi away.

I'm hoping even a "brute-force" linear constant-current regulator, running two or three high-power LEDs in series off the battery at 11.8V to 14.4V would be way more efficient than an incandescent, and avoid all the harmonics from switchers...
 
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Ubergeek63

Well-Known Member
I'm hoping even a "brute-force" linear constant-current regulator, running two or three high-power LEDs in series off the battery at 11.8V to 14.4V would be way more efficient than an incandescent, and avoid all the harmonics from switchers...
The EMI thing is mostly paranoia when it comes to LED switchers, but then I am a design engineer with the skill and resources at my beck and call to do it right.

You need to be able to keep the junction temps below 50C while dissipating 3W each...also something most hobbyists are unprepared for.

Dan
 

MikeMl

Well-Known Member
Most Helpful Member
The EMI thing is mostly paranoia when it comes to LED switchers, but then I am a design engineer with the skill and resources at my beck and call to do it right.

You need to be able to keep the junction temps below 50C while dissipating 3W each...also something most hobbyists are unprepared for.

Dan

I have a 200W AC-powered switching 14V power supply which I use to run my HF Ham rig which is reasonably clean (at least at frequencies I listen on); however, there are dozens of switchers in my house and in my neighbor's houses that are a Ham's worst nightmare.

I have designed and built switchers for use in aircraft avionics; to de-noise them, they had to be put in a double-shielded (box within a box) metallic enclosure, every wire into/out of the box had to have a ρi-section (C-L-C) low-pass filter in it, using coaxial feed-through capacitors, and series inductors between the box walls. The parts cost for the entire power supply more than tripled by the time the RFI was tamed. Most of the imported switchers we are getting today in consumer appliances and computer equipment is built to be as cheap as possible and radiate RFI like crazy...

As to the care and feeding of high-power LEDs, I can read Spec-Sheets and Application Notes :D
 
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Artificer

New Member
Refitting a '73 Avion travel trailer (caravan), I devised lighting using the 3 LED "under cabinet" lights, putting two in series. LEDs drop around 2.2 volts per. In a series string, 20mA is sufficient for general lighting. Meaning less than 1w resistor size..... Up to 30mA for brighter light. It would be better to use more lights than to increase the individual current. LEDs -do- have a finite life span.

Try starting with 100 ohms and 5 LEDs in series. In the States, I found the fixtures at a "Dollar Store" at 2 for a buck. Six bright white LEDs at that price was too good to pass up. This stuff comes out of Mainland China, you can find the LEDs bulk (>5000 pcs) for a penny or less each. In the US, repackagers usually mark them up by a factor of 100 or better. Then, the retailers get their cut. At the bulk price, using a couple hundred, and junk boxing the rest will still pay off.

Also fabricated a work light for an automobile mechanic buddy. It runs off 120VAC mains, has 60+ LEDs in series. Using a basic PNP transistor as a current regulator. Built the same thing for myself using 8 series strings of 5 LEDs to run off my truck battery.

The point of all this is that you will be looking at large quantities of LEDs, no matter what your source. Retail (and mail order) prices will be high, even in quantity. If time is not that big an issue, find a source for failed clusters. Usually only a few will be bad. Salvage the rest and reuse them. I used the under cabinet lights only because I also needed the lens and base rings.

Look to Hudson TelCom under the projects sub-page. I have documented refitting LED tail lights to the Avion. Mostly about the construction of the adaptor, but there are electrical prints as well that can be of use.
 

Artificer

New Member
After-thoughts: LED replacements are available for 1156 (back-up) lamps. Load is less than 80mA per, and they will plug-in replace the RV lamps in the bayonet base. You would need to fit a reflector of sorts, they are somewhat directional.
 

Ubergeek63

Well-Known Member
I have a 200W AC-powered switching 14V power supply which I use to run my HF Ham rig which is reasonably clean (at least at frequencies I listen on); however, there are dozens of switchers in my house and in my neighbor's houses that are a Ham's worst nightmare.

I have designed and built switchers for use in aircraft avionics; to de-noise them, they had to be put in a double-shielded (box within a box) metallic enclosure, every wire into/out of the box had to have a ρi-section (C-L-C) low-pass filter in it, using coaxial feed-through capacitors, and series inductors between the box walls. The parts cost for the entire power supply more than tripled by the time the RFI was tamed. Most of the imported switchers we are getting today in consumer appliances and computer equipment is built to be as cheap as possible and radiate RFI like crazy...

As to the care and feeding of high-power LEDs, I can read Spec-Sheets and Application Notes :D

Then we are both on the endangered specie list on the boards... I too have designed avionics :) As to the EMI, more often than not it is poor layout and lack of attention to details that causes the most problems.

Keeping things as small as possible goes a long way to improving things as does limiting rise and fall times and of course using shielded inductors instead of crap ones. Unfortunately EMI is normally only thought of when something fails the test instead of being an integral part of the design process.

Dan
 
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