LED problems

I replaced some of my 921 bulbs with LEDs. On some of the el cheapo LEDs, the wires were too short to make consistent contact in the fixture. Sometimes they'd work; sometime they wouldn't.

Sounds like the LED bulbs were overheating and shutting down.

Mine used 921s, too. I replaced them with LED panels from Dealextreme (www.dx.com). I got warm white ones, which are much more comfortable to my eyes that the more blueish standard white ones. I haven't had any problems with them other than they're a bit fussy getting them plugged into the socket.

They have small and large panels. The small put out a bit less light than the 921s, the larger panels put out the same or maybe a bit more.

The power consumption varies a bit between units, but this is what I measured for a couple. Lumen spec is what they claim, and seems about right. 921s consumes about 1.25A each, so these use like 1/3-1/6 the power.

size partnum draw lumens
----- ------- ------- ------
small 283830 ~200 mA 200 lm
large 283831 ~360 mA 400 lm

First thanks for all the replies. When this started it was the 1st. time I had a chance to use the bulbs. They are a 921 wedge type. We never hook up to shore power and everything else works as it should. They didn't all go out together. After the one died I tried a different one and moved the bulbs around resulting in the same scenario. At this point I put my original bulbs (incandecent) back in for the rest of our trip. I have a message in to the supplier and waiting for their input. This all started as a way of conserving my battery life, uggh. They are the wide range voltage bulbs.

This is not based on theories, I'm using them now while typing this on my tablet.

Look at his previous posts and you'll see where this attitude comes from

happycamper002 wrote:
Try hooking up a 67 ohm resistor on one of the lamps and check the voltage on the other fixtures without the resistor and you will be surprised at the difference.

Of course you can get a replacement but it is much cheaper with a ten cent resistor from Radio Shack...and save the other LEDs.

You did not ask OP what kind of converter type he has. Was it Old School or Hi Tech.

Wonders of the internet. . . everyone turned into experts overnight.

:R

Your on the "internet" and I really don't see your answer is much of a "expert" type of answer..

The OP BOUGHT NEW and expected it to WORK right out of the box.

The vendor OWES the OP a WORKING item.

The OP should not have to add ANYTHING to make it work, PERIOD.

The VENDOR should make it right by exchanging it with no cost OR giving the OP their money back.

YOU are making some very wrong assumptions and cobbling a resitor into the circuit WILL NOT FIX the problem.

Simply put, there is TWO different setups with LED lights..

Setup one is to put all LEDs into a series/parallel arraignment.

White LEDs NEED 3.0V-3.8V forward voltage to light, typically THREE LEDs are placed in series.. More than three and they will parallel the additional strings together..

Typically a small value series resistor will be placed in series with the circuit to manage the current draw..

Not all that efficient.

Newer more efficient way to manage the current draw is to use a SWITCHING VOLTAGE REGULATOR to drive the LEDs. This regulator regulator is a constant current regulator.

Resistor current limiting has a very narrow voltage range 9V-15V)..

Constant current regulator has a very WIDE voltage range (typically 9V to 30V).

Now right now you are saying "so what?"..

Well IF the OP bought a resistor current limited LED array it would have burnt up and never worked again..

IF the OP bought LEDs which use a switching constant current regulator (Which IS most likely what the OP bought), the REGULATOR CAN cycle ON/OFF if it fails or over heats..

Most likely the OP bought cheaply made LED modules which have cheaply made regulators and no amount of resistors you add to the circuit will ever fix the problem.


And how you have come to the conclusion of using 67 ohms is way beyond belief.. You have NO idea how many LEDs are in series (IE wired), no idea of how much voltage or current the LEDs need and no way to determine the wattage of the resistors that the OP would need without sending the resistors in to a flaming mess.

You MUST be rather clairvoyant to know exactly how the OPs LEDs are wired and all the parameters of the LEDs or just a self proclaimed internet expert.. :R

happycamper002 wrote:
Wonders of the internet. . . everyone turned into experts overnight.

You said it...

your bona fides are???

Where did this "67 ohm resistor" come from? That's ~0.2 A @13 V, far from the draw a 921 bulb, which the OP specifically said he was replacing, has (~1.25A). And, if you've ever seen 19 V, you should have fixed an obvious and serious problem, instead of saying here that it's not unexpected. Whatever, the OP could simply plug one of the removed bulbs back in without having to find a Radio Shack in the next state or try to figure out how to plug a resistor into a socket.

Try hooking up a 67 ohm resistor on one of the lamps and check the voltage on the other fixtures without the resistor and you will be surprised at the difference.

Of course you can get a replacement but it is much cheaper with a ten cent resistor from Radio Shack...and save the other LEDs.

You did not ask OP what kind of converter type he has. Was it Old School or Hi Tech.

Wonders of the internet. . . everyone turned into experts overnight.

happycamper002 wrote:

AidenJ wrote:
Recently bought 4 new LED bulbs to replace the incandecent ones for interior lighting in a truck camper. They are the wedge type 921 bulbs. The problem is they shut down after about 15-20 minutes. They will come back on after a short time, but then go back off. All 4 do the same and it doesn't matter what fixture I put them in. Any ideas?

You did not say that this happened when you are plugged in to shore power. I'm assuming the possibility that you could have 13.7v (as another poster had alluded) being fed to the lights which means you are plugged in to pedestal. (you couldn't have 13.7 vdc coming from the batteries unless your alternator is running).

Feel the LEDs when lit after a few minutes. If hot (not just warm) you are getting over 12.5v of power. I've seen 19.0 volts at the fixture when plugged in to pedestal. Quality made LEDs can withstand this above average power source. The cheap ones don't go thru a rigorous quality control. . . and eventually fail in a very short period. Maybe overnight.

SOLUTION:

Hookup a 67 ohm (plus or minus) 1 watt resistor in series with the light fixture . Even when you run your rig from house battery at nominal 12 volts, there would be no noticeable reduction in output lumens. With this approach your LEDs will most likely outlive you. :-)

Do this at each individual fixture, not at the fuse box because some loads are connected to the same circuit the fixtures are. . . and they may not function correctly like sensitive electronics, fans and solenoids etc.

19 volts when on shore power????? :E :E :h

YOU have a BIG PROBLEM!!!

There is no way or reason as to why ANY MODERN "12V" battery system should or could get to 19V when the converter AND battery are functioning correctly!

I call BS..

Now 14.4V-14.8V is a real possibility but not 19V.

The only possible reason you could have ever seen that voltage (19V) is if you have an old school analog converter with a big old heavy brute transformer which required a GOOD battery.. The battery would regulate the voltage and battery WAS required at all times..

As far as the OPs problem..

SEND THE LEDS BACK AND GET YOUR MONEY BACK!

You most likely bought at junk prices and junk you got..

Buy somewhere else (and hopefully a better quality).

AidenJ wrote:
Recently bought 4 new LED bulbs to replace the incandecent ones for interior lighting in a truck camper. They are the wedge type 921 bulbs. The problem is they shut down after about 15-20 minutes. They will come back on after a short time, but then go back off. All 4 do the same and it doesn't matter what fixture I put them in. Any ideas?

You did not say that this happened when you are plugged in to shore power. I'm assuming the possibility that you could have 13.7v (as another poster had alluded) being fed to the lights which means you are plugged in to pedestal. (you couldn't have 13.7 vdc coming from the batteries unless your alternator is running).

Feel the LEDs when lit after a few minutes. If hot (not just warm) you are getting over 12.5v of power. I've seen 19.0 volts at the fixture when plugged in to pedestal. Quality made LEDs can withstand this above average power source. The cheap ones don't go thru a rigorous quality control. . . and eventually fail in a very short period. Maybe overnight.

SOLUTION:

Hookup a 67 ohm (plus or minus) 1 watt resistor in series with the light fixture . Even when you run your rig from house battery at nominal 12 volts, there would be no noticeable reduction in output lumens. With this approach your LEDs will most likely outlive you. :-)

Do this at each individual fixture, not at the fuse box because some loads are connected to the same circuit the fixtures are. . . and they may not function correctly like sensitive electronics, fans and solenoids etc.