Hot Resistors

[EmmienLightFan]

I am running some "connectable" lights on a 30vdc 4 amp PSU.


The lights were originally powered by a 24vac transformer and connected to a multi function controller which I cut off. Before cutting it off I measured the voltage with my multimeter at 31vdc.


The lights come on normally on the new power supply, but the resistors on some of them get quite warm.

 

[David_AVD]

Have you tried dropping the voltage? I run my Big W (24V AC) lights on 30V DC. Some colour will run on 27V or so.

 

[i13]

How much current are the light sets drawing and how many series sections do they have? If you don't know how many series sections then just post the number of lights, wires within the set, channels and the number of places where there are less wires. I will work it out from there.

The voltage affects the current but it is the current that does the damage. I wouldn't be surprised if the LEDs aren't noticeably brighter when the current is too high.

 

[AAH]

That problem just gave me a cunning plan to work out what voltage to run the lights at as it's hard to work out from an AC source to a DC source what voltage to run at. If you had a digital thermometer you could do a measurement whilst on the AC plugpack and then do 1 on the DC power source and you could then adjust the DC voltage so that the temperatures match. Failing that you could do the tried and tested method of feeling the resistors an AC and DC.