LED Retrofit, not off the shelf! (lots of pics)

I've converted two single-dome fixtures in the coach, now I have three double-dome fixtures in the main room, and one in the bathroom to convert.

The white balance went a bit crazy on this photo, makes it look like I'm using yellow lights or something.

The fixture over the sink has a new double-acting switch in it, so I can have just the dome, or the dome plus the strip-light on.

Alsimon96, if you can post a picture of what you are working with I'll try to help you out.

I have been converting my fixtures to LED's but I'm having significant heat problems. The conversion is pretty simply - take the bulb out, use double sided tape to hold the LED panel in place, and use the adapter to plug into the socket. But the darn LED panels get so hot that it melts the double sided foam tape. What are people doing to solve this problem. I also tried converting a florescent fixture to LED. I used the double sided foam tape to hold the panels to the plastic fixture. The LED's were so hot they started distorting the plastic fixture. So in my opinion, the double sided foam tape cannot be used to hold the LED panel. And somehow the heat has to be dissipated. How have others dealt with these problems?

You really don't need anything more than an AM/FM receiver to see what's going on, if anything. The AM Band covers obviously AM, but is a good enough indicator on the low ham bands. Same for FM. It's close enough to Weather and VHF TV that you will hear it on the FM receiver if anything is there. Just find an open frequency and listen.

The ones I tested, if they were generating garbage on FM, it only got worse up on UHF, but YMMV.

HERE is an LED Interference thread from 2010 that might be of interest. My analyzer pix from these tests are on the last page where you can clearly see how bad things CAN get. But again YMMV.

(Edit: 'autocorrect' spelling)

A buddy is lending me a simple handheld scanner, I will try to tune in a weather station or something, and then turn my LEDs on to see if there is any affect.

Any recommended frequencies to try? I don't really know the capabilities of the scanner, like I said, radio is something I never got into.

Gordon - Just bringing it up as it is real problem. Most manf indicated they were within FCC specs so never put much effort in a fix or changing type of LED boards circuit regulation procedures. Some folks say they have never experienced it but if you ever find your self camping off the power grid and working with weaker OTA HDTV and WX Alert Radio signals I think you will notice it right away as a problem. Your on-board items will not work as well as your close by neighbors. It is not hard to notice you are experiencing RFI when you turn on your LED lights and HDTV goes completely blank. Turn the LED lights off and the HDTV comes back on...

Since I had started out with Command Electronics devices which performed very well for my retrofit I was pretty well committed before I realized I had RFI issues. My cheap way out was mod my dual lamp fixtures with three way switch (OFF-ON-BOTH) allowing me to mix the unregulated boards with the regulated boards. This give lights when camping off the power grids locations just using half of the light fixtures which had the non-regulated boards installed. At least I had control of the situation for my installs.

There are other problems with solid state devices that will bite the radio world as well with the high powered INVERTERs doing the same thing... Inverters and regulated LED light circuits sure play hard with amateur radio operations when camping off the power grids. These RFI signals are very broad in frequency which makes them hard to live with. In my experience with INVERTER some of the lower RF bands for amateur radio was totally unusable. All you hear on the radios were loud BRRRRR's every where you tune your radios.

Just things you have to learn to live with. There are more non amateur radio users and everyone has their rights to their electronics.

Here is some of CAMPERPAULS handy work working on his RFI issues... Those are 1/8-inch strip capacitors soldered inplace - very carefully soldered inplace I might add... Magnetic ferrite beads and twisting of 12VDC cables are about the first thing ones tries to help.


Like said by others on here it has been well documentated on the RV forums as real events. Not just Uncle Roy Ken having problems...

As long as FCC allows their regulations to be covered by having a statement in their specificitions that you may experience RFI issues and not require manf to fix the problems then it will continue... Read the fine print hehe... When you call the manf and report the issues right away you hear they are in compliance with FCC regulations.

Roy Ken

Interesting indeed. I wonder what impact the all aluminum shell of my KZ has on attenuating these signals.

I guess its my generation-x / millennial nature; I've never used any broadcast services other than satellites and cell phones. I forgot my truck even had FM radio until one day when the nav system freaked out and I had to reboot it, which caused it to restart into FM radio mode. Radio to me is either XM or Pandora. TV is from a cable or dish :)

Sorry Roy Ken, if we're ever neighbors at a CG and your TV is on the fritz, I'll use a flashlight ...err, that's an LED switcher too, hmmm... candles?

Gordon: FYI- it's been documented several times here of neighbors LED's killing adjacent TV's, I think that's why RoyKen was mentioning it.

Westend: I'll give ya a pat. I polished a plate the size of a scare light for my LEDZILLA project, but it didn't come out that nice. You've got some serious time into that one.

SCVJeff wrote:
The one thing you can do to help RFI coming off the boards is to twist the +&- together both in and out of the stitcher board. Start the twist as close as you can all the way to the LED board. Likewise to the power switch on the input side. When I was working on reducing RFI on some LED's I have, this has the single biggest effect on radiation coupling out the antenna.

Maybe Roy Ken can try this if he has any of his old regulated led lamps around. I don't have any radio receivers in use in my rig, other than my cell phone and it operates in the microwave bands... my coach radio plays tunes off a usb stick or bluetooth from my phone, and my tv plays movies from the phone or (ripped) dvd library :)

SCVJeff wrote:
Question: Why didn't you just buy 3000k 3W boards rather than building them?

I bought a bunch of these carrier boards from a start-up in Germany when the Rebel first came out, so it's less expensive for me to reflow my own at this point. The cheapest 3 rebel star I can find right now, built with the LEDs I want is almost $14 a piece, plus shipping. There are cheaper options out there, but that's not what I'm after. As far as the 'other' brand of high-power LEDs go, their new COB disks look interesting, but the high forward voltage is a turn-off.

Lumileds, before they got swallowed up by Philips was a cool little company. I've got some of their early prototypes and they actually sent a sales engineer all the way my little home town just to have lunch with me and chat about projects. But, that was ten years ago, not so much love from them now but I still like their products.

GordonThree wrote:

westend wrote:
Hey Gordon,
From my experience with heat dissipation, I don't think you're going to get much better dissipation by increasing the dimensions of the aluminum plate. Heat from devices like this transfer from conductive to convective in a fairly small locality. You may get better reflectivity, though.

Nice polish job on that block!

You are correct, increasing the size of the plate alone does not help much with convective cooling. My goal is to increase the thermal mass. If the LEDs are heaters, running on a fixed power, the more mass they have to cool, the less heat will be "trapped" inside them. Entropy of the mass is always working to cool it... at least, that's the theory I'm working off of.

As long as I can keep the system under 200F with high ambient temps, I'll be happy. I don't have anything fancy like a FLIR camera, but I am going to get one of those laser pointer temperature probes.

If the big slab of aluminum can't keep things cool, I'll ditch the plastic fixtures entirely and go with a recessed heat sink in the ceiling. There's a new piezo-electric LED cooler I've been wanting to try. :)

Thanks for the comment on polishing, it's something that is tedious as heck and no one gives me a back pat because they can't see it. ;)

Your theory on mass and entropy are spot on. I should have worded my other post better in that devices dissipate their heat into the mass in a very localized manner. If we use a device that has 10 C/W and wish to dissipate the junction temperature to 50C, let's say, we would find that the greater amount of dissipation occurs within a radius of twice the devices area. Temperatures farther out than that fall off quickly. This is the conductive heat transfer and is the reason why a finned heatsink is more efficient, it increases the area where conductive and convective transfer interface. Sometimes a finned sink isn't the right one, though. You also have the mounting pad that is spreading heat. I think you'll meet your heat goals with what you have.