Lightbulb problems: fixture or wiring?

[stevennlv]

All of my light fixtures use the LED so-called “lightbulbs”. The type that mine uses are all 3x5 LEDs. Most of them work fine. But the one over the kitchen sink keeps burning out bulbs quickly. AFAIK these LED bulbs are supposed to be fairly long lasting?

Look at the diagram below:

0 6 3 0 0
0 5 2 0 0
0 4 1 0 0

The “0” all indicate LEDs that are still working correctly. The numbers indicate LEDs that have failed and the order in which they failed.

The whole process takes about 90 days. When I put in a new bulb it will work fine for a while. Then LED #1 will start to blink. Shortly afterwards it dies and #2 starts to blink; wash, rinse, repeat through #6.

On the last bulb (one in it when we bought the trailer) it got to #6 blinking with 1-5 burned out after about 90 days and I replaced the bulb.

Now the second bulb has already burned out LEDs 1-5 and #6 is now blinking after about 90 days.

So, my questions are:

1) Is this dangerous? Will it cause a short / fire? Should I not be using that fixture?

2) Is this indicative of an issue with just the fixture itself or could this be an issue with some other part of the electrical systems of the trailer? Since it happend with two bulbs I wouldn't think it would be the bulbs?

3) Would the best approach to a fix be to just replace the fixture or should I try another bulb first?

Any help appreciated.

[stevennlv]

@Gdetrailer, thanks for the info and the link.

Yes, "type 921" is one of the things stamped on the backplate of the fixture. But I didn't realize that *any* 921 would fit the socket. I was looking for ones like the ones already in here that terminate in to two solder blobs instead of wires.

It was time for me to order some other stuff from Amazon, so I went ahead and got the ones you linked to b/c that will be enough to replace every bulb in the trailer with two spares for less than I would have paid for just two of the other ones.

[Gdetrailer]

stevennlv wrote:
OK, so cheap bulbs can't tolerate fluctuations from crappy converter.

The converter is beyond my means and ability to do much about right now. I can look to see if there are obvious issues like corrosion or loose wires, but that's about as deep as I can get right now due to injuries and lack of funds.

It doesn't surprise me one bit to find out this thing probably has a low quality and / or poorly installed converter.

We've been in this thing 6 months and everytime we turn around I'm having to do some kind of small maintenance to it due to either the lack of original quality or neglect from the first owner.

The bulbs I'm having issues with were purchased at camping world for $15 each. Personally I don't consider that cheap. But, it is what is.

So, after I figured out the type I need I saved two different ones at amazon to purchase in the future:

Bulb 1


Bulb 2

Would either of these be worth buying?

If not can someone drop a link to a quality replacement.

NB: I have no idea how any of this works. It's not like the old bulbs where I could just read the fixture and get the appropriate bulb. IDK if I can put totally dif "bulbs" in it? What I do know is that there's not much room in these fixtures and I won't be able to get anything too much bigger or shaped radically differently in to them.

And, for curiosities sake I just pulled the cover off of every bulb in the whole trailer. And all of them have what looks to me like scorch marks around the socket where the LED boards plug in. Is that normal or something I should worry about?

I would steer clear of both of the ones in your links.

#1, no specs in current draw, voltage range or even color temperature..

#2, no specs on voltage range or color temperature, does state amperage as .08A which is nothing more than a night light..

Both appear to be same design and from the pix uses resistors to control the current draw though the LEDs..



Better LEDs will have a bunch of parts on the BACK of the LED panel (IE switching current regulator)..

Looks like these..



Better LEDs manufacturers will state the voltage range, the current draw (or wattage) AND give you choice of color temperature stated in Kelvin (IE 2,700K which is incadescent, 4,000K which is similar to florescent light, 5,000K which is similar to sunlight).

The ones you linked are over priced and most likely will not be bright at all..

From what I can tell, you are looking for 921 LED replacements so use that in your search..

HERE is one that states voltage range, color temp and wattage.. Not to mention has a picture of front and back which at least tells me it has a constant current regulator..



Somewhere in the questions someone stated it is equivalent to 12W incadescent..

Keep looking.

[ktmrfs]

2oldman wrote:
The OP wants a simple version. The switching power supplies are for you technicians here.

simple versions and shore power are a BAD combination. converter will go to 14.6V occasonally and lead to thermal runaway on the lights with just a dropping resistor.

LED are a CONSTANT current device, NOT constant voltage. driven from a voltage source as they heat up, junction voltage goes down, current goes up more, leakage current goes up, LED gets hotter, get the picture.

for a trailer if you are expecting them to last any length of time you want ones that specify a wide operating voltage range, say 9-20V or more. these drive the LED with a constant current.

Otherwise they can actually get hot enough to melt the solder on the circuit board.

Anymore the goods ones are reasonably priced.

[2oldman]

Boy, it's hard to say. I didn't yet find the voltage spec on them. Perhaps you can poke around the internet and see if you can find that.

Scorching could be from the incans that were there before.. assuming they were there before.

Sorry this is so complicated.. sometimes leds are like that. I don't recognize that type of connector, mine are all the old cylindrical style like automotive bulbs. And my situation is unique in that I have zero voltage fluctuations.

[stevennlv]

OK, so cheap bulbs can't tolerate fluctuations from crappy converter.

The converter is beyond my means and ability to do much about right now. I can look to see if there are obvious issues like corrosion or loose wires, but that's about as deep as I can get right now due to injuries and lack of funds.

It doesn't surprise me one bit to find out this thing probably has a low quality and / or poorly installed converter.

We've been in this thing 6 months and everytime we turn around I'm having to do some kind of small maintenance to it due to either the lack of original quality or neglect from the first owner.

The bulbs I'm having issues with were purchased at camping world for $15 each. Personally I don't consider that cheap. But, it is what is.

So, after I figured out the type I need I saved two different ones at amazon to purchase in the future:

Bulb 1


Bulb 2

Would either of these be worth buying?

If not can someone drop a link to a quality replacement.

NB: I have no idea how any of this works. It's not like the old bulbs where I could just read the fixture and get the appropriate bulb. IDK if I can put totally dif "bulbs" in it? What I do know is that there's not much room in these fixtures and I won't be able to get anything too much bigger or shaped radically differently in to them.

And, for curiosities sake I just pulled the cover off of every bulb in the whole trailer. And all of them have what looks to me like scorch marks around the socket where the LED boards plug in. Is that normal or something I should worry about?

[2oldman]

The OP wants a simple version. The switching power supplies are for you technicians here.

[Gdetrailer]

2oldman wrote:
Roy said cheap leds don't have much voltage tolerance, and your converter is the source of fluctuating voltage.

Sort of.

I think Roy was talking cheap LEDs typically do not have built in switching power supplies for current regulation of the LEDs. Instead they use a simple resistor and some yet use NO resistor or switching regulator (three LEDs in series which each LED drops about 3.7V). These are the ones that typically do not tolerate much voltage change.

There ARE also CHEAPLY MADE LEDs which use poorly designed switching current regulators. These ones typically are the ones that create tons of RFI but also may not tolerate a lot of voltage change.

Then there is the ones that have PROPERLY WELL DESIGNED switching current regulator.. These ones do not come cheap and have no issue with 9V-30V..

Then there is the thousands of bargain basement Chinese manufacturers which peddle poorly designed, made, no Quality Control LED modules from not even "seconds" but thirds and fourths picked up from the cutting room floor parts that should have been put into the garbage.. THESE are most likely what the OP bought!

[2oldman]

Roy said cheap leds don't have much voltage tolerance, and your converter is the source of fluctuating voltage.

[westend]

You need to monitor the DC system to see if current or voltage is an underlying issue. This would mean known good batteries, converter output measured, and the conditions of all connections.
For this diagnosis, you need a hand-held meter.

[Gdetrailer]

stevennlv wrote:
OK, I'm going to chalk this up to being more than just one fixture.

I was sitting around last night with just the fixture over the table on; which is not something that normally happens.

It started getting dimmer in a cycle that ran maybe about 5 minutes? (I did not time it.) The bulb would be normal brightness for several minutes, then get dimmer for may 10 seconds, go back to bright, wash, rinse, repeat. During the cycles the bulb never got brighter than normal.

So, one fixture burning LEDs in a reproducible pattern and another fixture (maybe on the same circuit?) getting dimmer, but not brighter, in cycles. Where do I start looking for that?

Cheaply made with no QC..

Find a different vendor/brand..

With LEDs you WILL end up "experimenting" with different vendors/brands until you find one that has slightly better QC..

Took me quite a few "tries" before I found LEDs that last more than a few weeks and even then have had a few die after a year or to of use.

[stevennlv]

OK, I'm going to chalk this up to being more than just one fixture.

I was sitting around last night with just the fixture over the table on; which is not something that normally happens.

It started getting dimmer in a cycle that ran maybe about 5 minutes? (I did not time it.) The bulb would be normal brightness for several minutes, then get dimmer for may 10 seconds, go back to bright, wash, rinse, repeat. During the cycles the bulb never got brighter than normal.

So, one fixture burning LEDs in a reproducible pattern and another fixture (maybe on the same circuit?) getting dimmer, but not brighter, in cycles. Where do I start looking for that?

[stevennlv]

I have not noticed all my bulbs getting brighter or dimmer at the same time.

Right now we are perma-parked and always on shore power unless it is down.

I have a solar system that includes a smart charger / battery tender.

I have had this happen while parked at two different RV parks.

I do use cheap bulbs, but the same cheap bulbs are working fine in the other fixtures.

@RoyB: I'm just barely getting my toe wet for the first time in my life with anything to do with electricity. I can only guess that you sound like you know what you're talking about. But, it's all greek to me. So, once again a little more slowly please?

[RoyB]

The LED Assy has a DC VOLTAGE specification. Some LED's are operated with a small range of DC Voltage. I have some ceiling LEDs that operate in the 12-14VDC range...

If the LED ASSY has a built-in regulator then this range can be extended over a wider range... I used to have a LED ASSY that operated from 9-30VDC range...

You need to find out what range your LED ASSYs are specified for and then measure the operating voltage to see what it reads for this location...

I am only discussing a 12VDC LED specification.... LED's can also be a 120VAC unit...

I guess another question for is do you ever see all of the LED lights getting brighter and dimmer sometimes. this could be traced to your converter/charger unit may be starting to go bad for you... This could also be related to a battery going bad on you and being charged at a higher than normal DC Current causing the converter/charger working very hard trying to keep the battery charged up... This could be determined if you have lost any battery fluids which is a common failure sometime associated with a single mode converter/charger unit that only puts out 13.6VDC.

Need to do some DC voltage measurements..

In my trailer setup my battery DC volatge without being conncted to shore power will read from 12.0VDC to 12.6-7VDC depending from its charge state.

When on shore power my on-board converter/charger will only produce 14.4VDC-13.6VDC-13.2VDC smart mode charging levels.

As you can see with this my 12V operating range is only 12.0VDC to 14.4VDC. There is no other source in my trailer setup that will produce any higher DC voltage under normal operating conditions.

Both the converter/charger 12VDC output and the Battery 12VDC output feed the same point on the 12V Distribution Panel so that your trailer can operate from both shore Power connections or off the Battery when OFF-GRID...

Roy Ken

[DrewE]

I would check the socket and the connections to it, making sure they are making good solid contact. My initial gut feeling is that this may be heat-induced, and a poor connection at the socket would cause localized heating. (My second thought is that it might be moisture related particularly if the LED bulbs are cheap quality ones, since this is over a sink.)

Since this is the only light doing this, and I assume the same sorts of bulbs are used elsewhere in the RV, I would tend to suspect it's not something more general with the RV electrical system.