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Help with MR-16 LED lights

BillFear

Well Known Member
Decided to buy a couple inexpensive 12volt LED MR16s (3x3watt crees) to replace my 75watt halogens in the wingtips now that we have added Duckworks HIDs for the real landing lights.

Love the light they make and the low power usage but as expected the drivers interfere with the radios big time. Anyone have any success building a noise filter that will work with the noisy driver that comes in these lights??

Any input would be appreciated.
 
Bill you must have finally gotten those lights.

Basically large fluctuations of current turn the supply wire into an antenna transmitting a bunch of high frequency noise.

Shielded twisted pair supply wire, don't ground at the tip, but return all the way back to your ground block. 100mH choke in series with the power, as close as possible to the light. 1uF 20V ceramic cap across the power inputs. That will take care of high frequency stuff, you can use additional progressively higher values for caps depending on the frequency of the noise if present.
 
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LED help

Hi Bob,

No can do on the wiring, it is in and staying! I just tore one of these apart and it appears they have 3 cree xr-e leds in series. Can I just get rid of the driver board and run them directly from the 13.8v supply power. Or can I add a resistor which I understand are completely quiet.

Cree specs show 3.7 volt forwarding voltage and 1000 ma forwarding current at 3.7 volts for the XR-E diodes.
 
Resistor is not a good idea for high intensity LEDs because as the bus voltage varies so will the current since it will just be proportional to that voltage, which may exceed the LED's maximum current ratings. Therefore you can't run safely at maximum current and you won't have the maximum brightness.
 
Led vs resistor



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this is 2 sets of 3 Cree lamps in series. I am using a 2.5 ohm 10 watt resistor in series with each 3 lamp set. You are correct that the amps drop with volts. I have a plane power alternator and odyssey battery. My Dynon reports the voltage as 14.7. at 14.7 volts, the current is .98 amps. The aircraft voltage does not drop much with low power on landing, and I am very pleased with this set up. There is zero rfi. The dropping resistors are absorbing about 2.7 watts of power. WAAAY less heat than the 75 watt mr16 heat lamps er, landing lights.
 
Pic of my wingtip lights. The LEDs are Crees, larger one is the landing light, the smaller one is a taxi light. Works very well.

photo.JPG
 
Send us your specs

Bob/Larry, please send the specs on the CREE LEDs you used.

Kurt, I would not recommend the MR16 I bought. The controller is very noisy. Experimenting yesterday, I bypassed it and ran the 3 leds in series with 4 ohms to attempt to get 1000ma thru them. They were very bright, for a minute and then the solder melted and the LEDS feel off the little round board they were attached to. (partially my fault as it was no connected to its heat sink). I think the mfgr in China quoted the wrong LEDs in the assembly, they claimed they were Cree XR-E, who knows what they really are.
 
Bill I think you caused yourself some unnecessary grief, an inductor and some caps will take care of the noise.

Cree's:
http://www.dealextreme.com/p/5-cree...drop-in-led-module-52-7mm-42mm-8-4v-max-35241

Taxi light:
http://www.kaidomain.com/product/details.S009853

XM-L T6's Bill is using:
http://www.dealextreme.com/p/t6-3-led-lamp-cap-9-22v-100483

I've been resisting the urge to try the T6's because the Cree's are plenty bright and more than adequate for use as landing lights. I experimented with 75W halogen MR-16's and the Cree's by setting up a step ladder on our runway at night to see how well they worked, and there's really no comparison.

The Cree light assembly draws 910mA.
 
Linear regulator

Have you considered an LM117K/T linear regulator? With three lamps in series it would only sink around 4 watts. A small heat sink, a 1.2 Ohm 2 watt resistor and a .1u input filter is all that you would require.

http://www.ti.com/lit/ds/snvs774l/snvs774l.pdf

Look at page 18 for an example in this pdf
 
led part numbers

these are digikey part numbers:
955-1033 Cree MCE4WT-A2-0000-00M02-STAR-SR $22.50 ea.
the resistor is a TMC10-2.5 $3.60

the reflectors are 711-1065 $2.30

The reflectors are rtvd in place. They don't fit perfectly, a Digikey tech said they were intended for a led chip that was not bonded to the star heat conducting circuit board.

The heat sink is homemade on my cnc. I could probably be talked into making some for sale if there was enough interest. It is made out of 1" bar with the cree mounting pads at the same angle as the wing tips on my 2010 RV7A. The crees are attached with 256 screws. You still need to add some washers to angle it down a bit.


LM117T....With a couple extra transistors you can hook up the LM117 in a current regulating mode. I have not tried it, but I suspect the noise level would be quite low since it is a linear regulator as opposed to the switchmode regulator that virtually all of the led drivers are. The down side of either the resistor or the LM117 is that you are wasting a bit of power dissapated accross the device. I'm just saying the resistor is stone simple, and it works. Ask me in a year or so.

One point to consider is that the leds are wired in series so if one fails (in a set of 3) that whole section fails. Of course if a light filament fails, same same.

I set mine up on 2 circuits, landing and taxi so if one fails, I still have 3 more ( 2 sets on each wing tip)
 
WING TIP LIGHTS

BOB - very nice setup.
you provided the source & part#s for the landing & taxi lites. can you do same for the strobe & position lites, for the electrically challenged?
any chance of a picture of the back side? did you heat sink any of the lites?
thanx
keith
 
Nav lights: http://www.ledlight.com/s25-36-led-light.aspx
Bases: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130454492553#ht_3356wt_1124

Strobe lenses are Whelen wingtip strobe lenses purchased from Van's.
Strobe bulbs are Nova hide-a-flash bulbs.
Both are held together from behind with a simple aluminum bracket made of .025 scrap.

The nav lights were made with some small pieces of aluminum tube turned on the lathe so the bulb body is recessed, with the holder glued into the tube with RTV.

I have somewhere in the neighborhood of $120/wingtip for all of the lights you see.

I've been wanting to mess with off-the-shelf LED strobes for police cars but I have to pick my battles wisely if I want to get this thing flying this year. :)
 
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any chance of a picture of the back side? did you heat sink any of the lites?
thanx
keith

Keith I will post pics next time the wingtips are off. I put the wingtips on with piano hinge, so it takes all of 30 seconds to take them off. It was quite a bit more work to fit them this way but I am sure glad I did. No heat sinks on any of the lights but I machined all of the fixtures out of aluminum and either glued or screwed them on, and I'm sure they are dissipating some heat. Suprisingly the Cree landing lights barely get warm to the touch but the XM-L's used for the taxi lights get significantly hotter and I'm thinking I will have to heat sink those.
 
MR-16s

hi Bob,

Never was able to get dealxtreme to deliver the XML lights so I bought some household MR-16s off Ebay to experiment with.

They have 3 cree CRE leds and claimed 580LM at 12volts. The light was great but the controllers were very noisy so I cut them out and replaced with a 3 ohm resistor. Was trying for around 1000ma and they were very bright right up to the point where the LEDs melted the solder and fell off the PC board. Turns out they probably are rated for more like 600ma plus I did not have them attached to the heat sink at the time.

I have one left and will probably try again with it.

Question, do you have the details on how to build a filter to kill the noise from the constant current controllers?
 
Thanks Bob

I will give the noise filter and try and let you know how it works for me.

Thanks again for all of your help.
 
NO GO ON NOISE FILTER

The noise filter with choke and caps had no effect on the RFI noise the CC controller was making.

Went back to the 4 ohm resistor, this time with the LEDs mounted in the heat sink and it works like a champ and completely quiet on the radio. I tried feeding the system with both 13.8 volts from my Power supply and around 12 volts from a car battery and I could not tell any difference in the light. Left them on for about 30 minutes, they get pretty warm but not hot. They draw just over 1 amp per side which is way better than the 75watt halogens.

I am going to give this setup a try in the plane. This is the unit I bought off ebay

http://www.smartop-led.com/productshow204.html

about $15 each. You can easily take them apart and bypass the controller board.
 
Did you ever shoot those photos of your Landing/Taxi light install?

Keith I will post pics next time the wingtips are off. I put the wingtips on with piano hinge, so it takes all of 30 seconds to take them off. It was quite a bit more work to fit them this way but I am sure glad I did. No heat sinks on any of the lights but I machined all of the fixtures out of aluminum and either glued or screwed them on, and I'm sure they are dissipating some heat. Suprisingly the Cree landing lights barely get warm to the touch but the XM-L's used for the taxi lights get significantly hotter and I'm thinking I will have to heat sink those.

Hi Bob,

I really would like to see those photos
 
MR-16 LED lights

Tested the converted SMARTLED lights last night after dark and I am pretty darn happy with them as taxi and wig-wags. They light up the area nicely for only about 550 lumens each and with the resistors replacing the controller board they are completely quiet on the radio. My lights have a 45 degree pattern so they wash the general area in front of the plane nicely. not bad for $15 each and a savings of 12amps over the halogens. They fit in the existing MR-16 wingtip mounts.

We added 55 watt HID duckworks in the leading edges for the landing lights.
 
Lights and More Lights

At this point I think I'm going to roll my own HID lights (using DDM Tuning HID kit) for the landing lights making use of the Duckworks leading edge mounts. I'm still working on the remaining lights.

I've done some preliminary testing on the nav lights with some LED stars. Those look pretty good. I'm going to take some measurements soon on the intensity and based upon those measurements decide if I have the right number of LEDs.

For the taxi lights I'm going to do with the SSC P7 LED emitters mounted in the wingtip following the path of others here. This looks like a good, inexpensive solution. I ordered the reflectors and star at the location Bob suggested. Total bill about $40, amazing. I'm still not clear on exactly how to mount reflector assembly so that it is at the correct angle. Once I get the reflector/heatsink I'll figure something out. I saw a reference to using aluminum tubing, but I'm unclear about how to use it other than as an extension to the reflector.

On the LED strobe front I'm still trying to decide if this is worth the effort. I was about to just go with the xenon strobes until I realized how much a power unit that would flash all three strobes cost. My LED solution using the same type of LEDs as my NAV lights would require alot of LEDs. I may look at a SSC P7 solution when I get a little more time.

I'm planning on designing a constant current controller board to run all of my LEDs in the wingtip. One will be needed in each wingtip. That would be the LED landing light, LED nav light, and maybe the LED strobe. If anyone has any interest in such a thing let me know I may be able to build some extras just to keep my cost down.
 
Shielded twisted pair supply wire, don't ground at the tip, but return all the way back to your ground block. 100mH choke in series with the power, as close as possible to the light. 1uF 20V ceramic cap across the power inputs. That will take care of high frequency stuff, you can use additional progressively higher values for caps depending on the frequency of the noise if present.

Rocketbob, need some clarification. My setup now: No shielded wiring with these MR-16's, Maxxima 5 Watt LED MR16 Cool White Spot Bulb - 260 Lumens (MLB-16550S), breaks squelch at any setting. Finally got them to flash with B&C SSF1 flasher using 2-75 ohm resistors in parallel at each light.

Is it acceptable to run the shielded pair only from the switch to the LED MR-16, or does it also have to come from the power to the switch? Also, by not grounding at the TIP, do you mean to NOT ground the coax at the light?

Thought of another clarification: Why twisted pair? If one conductor is the voltage source, does the second conductor and the shield get connected to panel ground??
 
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Are you guys doing all the lighting work once the wings are complete or did you install and wire them during the wing build? I just started on my QB wings so I am wondering if I need to figure this stuff now, or just build the basic wing and install lights later. Thanks. Great Ideas here!
 
Pic of my wingtip lights. The LEDs are Crees, larger one is the landing light, the smaller one is a taxi light. Works very well.

photo.JPG

Hi Bob,
Your lights look great.
The landing light says it is 8.4V max. How did you get it to work on 12V system? Can you show us the mounting if you get a chance plse?
I am novice at this, so keep it simple! I would like to try your setup. Can it be made to wig-wag?
Thanks.
Johan
 
The Cree's worked fine with 13.8V. Since then I've switched to these:

http://www.dealextreme.com/p/t6-3-led-lamp-cap-9-22v-100483

Brighter and temporarily wired them up to the RV-6 I fly...no noise whatsoever.

I machined the mounts, so unless you have access to a milling machine you will have to find a different way to mount the LEDs.

Thanks Bob,
What mounting bases goes with these LED's (appears to have inner and outer spring) as well as your smaller wingtip light?
Johan
 
Its made for a flashlight upgrade. So you remove the springs and solder wires on where the springs were soldered on.
 
Wingtip Lighting Kit Partslist?

I'm slowly working on my lights as a background task as I work on the rest of the wing. I have a couple of options for the taxi lights. I bought a pair of the P6 LEDs with MR16 reflectors. Right now I'm investigating how to mount them.

I've looked at the Vans wingtip mounting approach and I could duplicate that arrangement. I'm wondering if anyone has the parts list for that wingtip lighting kit. I might be lazy and just order the parts. Otherwise I'll just make my own version depending on the cost from Vans.
 
I'm slowly working on my lights as a background task as I work on the rest of the wing. I have a couple of options for the taxi lights. I bought a pair of the P6 LEDs with MR16 reflectors. Right now I'm investigating how to mount them.

I've looked at the Vans wingtip mounting approach and I could duplicate that arrangement. I'm wondering if anyone has the parts list for that wingtip lighting kit. I might be lazy and just order the parts. Otherwise I'll just make my own version depending on the cost from Vans.

I have a PDF of the instructions which I got from Van's...shoot me an email via PM and I'll send it to you.

The only part which might be a pain to fab up would be the rear half of the bulb holder, because it is flanged on the large hole to fit the bulb.
 
Partial RF Interference with MR16 LED's

I recently fitted 4 x 6 watt MR16 LEDs into the Vans Wing Tip lighting kit fittings (used a single 50W halogen for test phase) and thought all was OK as no interference on my Funkwerk ATR833 COM or FlightCom 403 intercom. Up to the problem flight I had not seleceted a radio frequencey greater than 126.00 then I selected 129.9 and lots of white/pink noise. I eventually found out it was the MR16 LEDs that I use for recognition not night flying as Day/VFR only in the UK. I contacted my avionics dealer and he said the radio had been modified for better RF resistance and asked me to contact another dealer for ferrite rings.

Today I tried out the ferrites as close to the noise source (LED's) but they made the matter worse as the noise now occurs above 125.0 so I have removed the ferrites and seek further advice as the dealer is away on holiday.

Except the MR16's (grounded at wing tip rib) all the aircraft wiring uses a single point ground bus at the firewall. The wiring to the wing tip is not shielded and I will not re-wire it - I'll go back to low wattage halogens if necessary (wired for LED's not the Vans 75W haogens). The antenna cable is RG-400. I have no noise issues with the NAV/Strobe LED's. Any suggestions please?

Bob Ellis
www.rv-8.co.uk
G-JBTR having a new lease of life with this wonderful aircraft.
 
The Cree's worked fine with 13.8V. Since then I've switched to these:

http://www.dealextreme.com/p/t6-3-led-lamp-cap-9-22v-100483

Brighter and temporarily wired them up to the RV-6 I fly...no noise whatsoever.

I machined the mounts, so unless you have access to a milling machine you will have to find a different way to mount the LEDs.

Do you have any chokes or noise suppressors installed with the T6s, or are they powered directly from the plane power just using shielded wire and running the ground back to the main ground bus?

Thanks!
 
What drivers are being used to deliver constant current to the XM-L cree's ?

Are you guys using something like this LuxDrive? Is that what is generating the electrical harmonics?

http://www.ledsupply.com/0a009-d-v-2100.php

Thanks

I sent a link to the Cree T6s to ledsupply.com and asked them basically the same question and their response is below. It appears that these lamps have the driver built in which would make sense as they're designed as drop-in replacements for high-powered flashlights.
====================================
I had a look at the link you sent for the 3-Up XM-L light. Since the input voltage is listed as a range (9-22V) and the documentation lists a constant current of 2.2A it would appear that this light already has an LED driver. If this light does have an LED driver you should not connect it to the BuckBlock driver. If an external LED driver is needed, the input voltage is usually listed as a discrete number and the drive current is listed as a range.

I can't be absolutely sure as I didn't see a link to the actual data sheet. You may want to contact the manufacturer to be sure.

=====================================
 
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