Halogen to LED Issue

[racclarkson@gmail.com]

Someone, I know, has had this happen to them.

I am replacing my 20 watt 12 volt halogen bulbs with JC G4 12V-24V LED 4.5W 5730 LEDs. On a four or more fixture circuit, no problem. On each of (3) three fixture circuits, the LEDs give quick flash--that's it, no light. If I replace just one of the LEDs with one of the old halogen bulbs then everything lights up. Having recently replaced one of the 110v to 12 volt transformers, I know all three circuits are independent of each other and there are no breaker trips.

So what's up?

25888

[sgharford]

Had something similar happen in my jeep when I replaced cabin lights with LED. There was not enough resistance in the new LED light bulb so the canbus would not recognize there was a bulb in there and simply would not supply power. Had to find an LED with more resistance, that solved the problem.

[Cricket]

Had something similar happen in my jeep when I replaced cabin lights with LED. There was not enough resistance in the new LED light bulb so the canbus would not recognize there was a bulb in there and simply would not supply power. Had to find an LED with more resistance, that solved the problem.

Yep, not enough load for the circuits in the transformer to kick in. What size transformers did you install, wouldn't need much for 3 of the led bulbs?

[racclarkson@gmail.com]

Thanks guys, makes sense. The transformer I just replaced was 75 watts, so that's way more than 3 of these will pull. Since I posted, my hallway four light circuit quits after 3 or four mins, same symptoms. My VIP has three on a circuit and it's been working continuously for an hour, but with one halogen in place.

Everyday I learn something new. I'd like a day off now and again.

[tonytrakovich]

Did you replace the transformers with led drivers or regular wire wound transformers? Led are DC devices and should be run by a led driver that supplies DC voltage. LEDs are also polarity sensitive. Hook up wrong way and they don’t work. The dimming in also different on led. AC devices just control voltage. LED dimmers actually pulse (very fast) to dim. LED drivers will not care about minimum load. I know some led are rated for ac and dc voltage. I have found that running them on ac voltage shortened their life.

[davidwigler]

These work great:

https://store.marinebeam.com/hatteras-32v-to-12v-waterproof-dc-dc-converter/

[racclarkson@gmail.com]

Thanks, as I mentioned my input is AC.

[Pascal]

Make sure the transformers are 120 AC to 12 DC. Some are 120 AC to 12 (or 24) AC and some LEDs will not work on AC.

[Boatsb]

I just pulled 2 120 volt to 24 volt a.c. transformers from a customers lighting circuits.

A.c. is not good for less. Also a 75 watt transformer should be fine if it's compatible with the led lights but seems that lnes not.

Cars have monitoring of dc circuits to report lamp issues so when changing to led lamps they many times see it as a blown incandescent.

[Reefgeorge]

If you are working with raw LED chips or wafers then you need to calculate the proper power supply/driver which can be constant current or constant voltage. The basic point is to supply a regulated power supply to meet the needs of the LED chips but not burn them out, especially as they heat up and change resistance. I did this engineering work to make my own high output LED spreader light assemblies doing heat sink calculations, using Cree LED wafers and constant current drivers but I just happen to like this stuff. Most of you are probably not designing LED assemblies from scratch using raw components so this may never apply.

Next are integrated assemblies that can take a more common form of power as might be available in an existing socket so that the LED product is plug and play with 100 year old technology. One example are LED's that look like incandescent light bulbs with a std screw base for say a living room lamp. This product takes AC line voltage, rectifies it and supplies the correct regulated DC power to the basic LED elements/chips/wafers.

Then there are components like what we are talking about here. They are also most likely intended to replace an existing incandecent solution so they may be able to take AC power or may need DC power but are likely to have some elements on say the back of the wafers or boards that perform the regulation function. I can't find much on the LED "lights" being discussed here so I don't know what power source and range are acceptable but I suspect that it is an unregulated AC and/or DC voltage. What does the spec sheet say? Are there components on the back of the board or are these raw LED elements?


George

[davidwigler]

Thanks, as I mentioned my input is AC.

Sorry I missed that detail. Can you pull all the circuits and feed them from one 12 volt breaker or junction box?

[Briankinley2004]

This may not apply in your situation but most of the LED's I have messed with are polarity sensitive so if you dont have the polarity correct on one of them it could possibly cause issues.

[Reefgeorge]

This may not apply in your situation but most of the LED's I have messed with are polarity sensitive so if you dont have the polarity correct on one of them it could possibly cause issues.

I believe that the power source is AC which has no polarity, only attention to hot vs neutral to manage safety. If these LED's accept AC then this is not the issue. If AC is in fact the power source and these LED's require DC then thats the issue, then attention does need to be paid to polarity and if these are raw LED chips, then also regulation.

George

[racclarkson@gmail.com]

Well I'm going with sgharford and cricket. Well done guys. In lieu of new transformers/ drivers...


Regarding the requirement of the electronic transformer: explained later in this post, insufficient load (http://www.cycloflow.com/2014/05/electronic-transformers-and-low-voltage.html#minimum_load) will cause intermittent operation of the electronic transformer, if it is below its "stated" minimum load. Sometimes this insufficient loading manifests itself as a pronounced flickering effect or more usually nothing.

Due to the way the voltage is generated internally within the electronic transformer, it is unlikely to damage the LED if it fails to meet the minimum load requirement.
A workaround, if your electronic transformer has a minimum load and it is feeding several light fittings but the sum of the LEDs alone does not reach this minimum value, then you can have one light fitting as a standard halogen bulb and all the other bulbs as LED lights. The combination of the Halogen and LEDbulbs, ensures that the minimum load requirement (http://www.cycloflow.com/2014/05/electronic-transformers-and-low-voltage.html#minimum_load) is met and the electronic transformer operates properly. Otherwise you will need to get either a dedicated supply for LEDs or another electronic transformer that is capable of running from a 0 watt load (http://www.cycloflow.com/2014/05/electronic-transformers-and-low-voltage.html#affiliate0w) (ie no load).

Thanks again!

[Reefgeorge]

I've never encountered this issue. Are these electronic "transformers" dedicated to these LED's, dedicated to your prior halogens or something else entirely?

George

[SKYCHENEY]

I try not to use transformers, if possible. If you have 12vdc, why not use that instead? Rewire the circuit and forget the transformer.

[racclarkson@gmail.com]

I try not to use transformers, if possible. If you have 12vdc, why not use that instead? Rewire the circuit and forget the transformer.I don’t have 12v handy. I’m not understanding why I would want to take out 110ac-12v transformers to install 32-12v transformers. This ain’t broke.

[Boatsb]

I use imtra fixtures. D.c. 10 to 40 volt. No issue with converting dc to dc.

[racclarkson@gmail.com]

Scott, thanks.

[tonytrakovich]

I took the big, bulky, heat generating, power hog AC transformers out and installed one of these.https://www.amazon.com/gp/product/B00WQWA50A/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1My ac/dc led are lasting longer and there are no issues with LEDs not lighting regardless of load. This model is 35w and is probable big enough for most applications on the boat.

[UNIQUE_NAME]

I took the big, bulky, heat generating, power hog AC transformers out and installed one of these.https://www.amazon.com/gp/product/B00WQWA50A/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1My ac/dc led are lasting longer and there are no issues with LEDs not lighting regardless of load. This model is 35w and is probable big enough for most applications on the boat.



i used https://www.amazon.com/LPV-100-12-Single-Switching-Current-Voltage/dp/B00YF3FIFU which was way overkill with a https://www.superbrightleds.com/moreinfo/single-color-dimmer-switches/slvdx-60w-led-switch-and-dimmer-for-standard-wall-switch-box/1181/
when i converted my orignal 120v salon lights. no problems 2 years in.

[Reefgeorge]

Electronic transformers, then yes in some designs there may be a minimum load requirement to excite the internal oscillation process that produces the voltage reduction.

George