simple L.E.D. question

[V.W.Dave]

Ok so I will be the first to admit I am not good with auto wiring.

The simple question I have is will LED lights off a truck (24v) work on a 12v system?

I know 24v globes don't but I didn't know about LED's.

The reason I ask is a mate of mine repairs truck trailers for a living and when he gets a trailer in with one broken tail light and they can't match the good one they replace both. He has about 30 odd ball LED's in his tool box. I can put them to good use if they would work.

[squizzytaylor]

Generally no unless they are a specific multivolt unit.

[Dooley]

Basically the leds will not have enough voltage drop across them, so no.

The solution would be to up the voltage...

[V.W.Dave]

hmm ok. I will have a look and see if any of them say they are multi voltage but if not I don't think its will be worth the hassle to make just the lighting system 24v

Thanks guys

[DamTriton]

Most LED tail light assy's I've seen tend to give a 9-30 volt range.

Best advice I could give would be to get one and try it, even a physically broken one with LED's still intact will give you the answer you need.

You are not going to damage a 24v LED byrunning it on 12v.

[Harb]

They will work......

[V.W.Dave]

Most LED tail light assy's I've seen tend to give a 9-30 volt range.

Best advice I could give would be to get one and try it, even a physically broken one with LED's still intact will give you the answer you need.

You are not going to damage a 24v LED byrunning it on 12v.

As I said I am not good with auto electic I have always been a heavy line guy. with them being LED they can't burn dim they are either off or on right?

[Harb]

Leds are current devices....if the current is low they will dim.....but at that point your battery will be long gone

A combination of voltage and current make them work, but if the current is not limited they will soon run away and burn out...... the voltage is less important, but they should be fine at 12v and were probably meant for operation over a range of voltages as suggested 9 - 30 odd volts

[-Scott-]

Leds are current devices....if the current is low they will dim.....but at that point your battery will be long gone

A combination of voltage and current make them work, but if the current is not limited they will soon run away and burn out...... the voltage is less important, but they should be fine at 12v and were probably meant for operation over a range of voltages as suggested 9 - 30 odd volts

Sort of. Light emitting diodes emit light from a "forward voltage drop", which is (roughly speaking) fixed for any given LED type. Traditional single colour discrete LEDs have a forward voltage drop in the range of 2V, and will typically operate in the range of 10 - 20mA. Traditionally, circuits need to be designed to ensure that only the desired amount of current flows through the LED. Apply too much voltage and they can become a NED - a Noise Emitting Diode, which is typically a "one shot" device.

Automotive LED assemblies have inbuilt power supplies that take a DC power supply and turn it into whatever current / voltage is appropriate for the array of LEDs.

Harb is right that a 24V assembly will probably work on 12V, and as others have noted, 12V won't break it. If it hasn't been designed well it may not work at peak efficiency on 12V, and may appear dim - but I'd be surprised if this happens. As noted, most devices these days are built to operate over a wide range, and will be happy on either 12V or 24V - but it's not guaranteed. In particular, don't assume a device sold for 12V will work on 24V - check the specs carefully.

[V.W.Dave]

Ok thanks guys. I will just grab a few of them and try them.

[Mr DJ]

Have you tried them yet ?
How did it go ?

[V.W.Dave]

I stopped in at the auto elect around the corner and asked the same question and got the exact same answer. He had a set sitting there and showed me that it would work. Now this is MOST NOT ALL will work. As already said it all comes down to the LEDs range of use. Most LEDs have there working voltage on them. 12-36 or 12-24 is commen.