12 volt LED voltage range?

[rlphoto]

Hello, I am setting up 12 volt systems in 2 campers I am building with all LED lighting.

I already have 2 110v to 12v power supplys. They are about 25 years old but work with no problems other than the no load voltage is 14.25 volts. Dont know if that is common or not.

What should the no load voltage actually be? The ones advertised are 13.6 to 13.8. I would rather not buy new ones if I dont have to. But I dont want to burn up my expensive LED lights.

Thanks!

[vrooom3440]

Wow a month and no reply...

What were the LEDs originally intended for?

Reason I ask is automotive electrical (the most common 12v electrical systems around) can run anywhere from 10.5v up to about 14.8v. Most voltage sources run a higher voltage without load than with load. Your car will probably run about 14.2v until you turn on the headlights and then drop down to 14v. Turn on an electric engine cooling fan and it will drop even more.

A typical battery charger will run above the rated 12v of the battery so there will be reverse current into the battery to charge it. Same thing happens with the alternator on your car.

If you are too concerned you could run a voltage dropping resistor on the LEDs. They are fairly low current so it probably would not take much.

[brian_bp]

I agree that it really matters what the "expensive LED lights" are designed for. The LEDs themselves need much less than 12V, but when assembled into a light they may have various configurations and supporting components, from sophisticated controllers to simpler dropping resistors to nothing at all.

Some units are designed to handle the variation which vrooom3440 mentioned in automotive systems without much change in performance, some are designed for the highest voltage usually seen in cars (and are just dimmer at lower voltages), and some will fry if given much more than exactly 12V.

[rlphoto]

Thanks for the reply's, These are automotive bulbs sold by some place in California that has no idea about what they are selling. The numbers they told me where the best operating range, not the max voltage. It is an automotive 1156 bulb DUH, SO anyway I ended up making a converter out of a computer power supply that only puts out 12.5 volt, so end of problem. My 25 yr old 13.8v converters where putting out 14.2 volts so I put them back away for another 25 years.

[Rigsby]

Ive started to install led lights into my build. The ones ive used are from a truck and are rated from 10v to 36v, so i should be safe , even when the battery is on charge
steve

[DonK]

There's a lot of good LED info at http://www.superbrightleds.com/

Their 1156 offerings are here: http://www.superbrightleds.com/tail-brake-turn.html

Note that their operating voltage is 9 - 14.8 volts. It may not be the same for yours, though.