LEDs at Lower Voltage

[EmmienLightFan]

I have 4 strings of 36v LEDs.

 

Is it safe to use them on a 30 volt power supply? Because of the decreased voltage, will the current increase?

[robongar]

If I had to take a guess, I don't think they will work. Have you tried them? However, being LED. I don't think the load will increase very much. I guess you could try wiring them in series.

Edited January 16, 2017 by robongar

[TheDucks]

I suspect you might find an adjustment (pot) inside the PSU that you could fudge a bit more, but not to far. the over voltage (crowbar) might trip.

34V is -5%  (a common VCC tolerance)  Bigger power wires to the Node to avoid IR losses

 

 

[k6ccc]

You will not damage them by using a lower voltage, but they may not work right. You may get light out, but will almost certainly have a color shift at the very least, and maybe some colors won't light at all.


Sent from my Droid Turbo via Tapatalk, so blame any typos or spelling errors on Android

[EmmienLightFan]

2 hours ago, k6ccc said:

You will not damage them by using a lower voltage, but they may not work right. You may get light out, but will almost certainly have a color shift at the very least, and maybe some colors won't light at all.


Sent from my Droid Turbo via Tapatalk, so blame any typos or spelling errors on Android
 

 

3 hours ago, TheDucks said:

I suspect you might find an adjustment (pot) inside the PSU that you could fudge a bit more, but not to far. the over voltage (crowbar) might trip.

34V is -5%  (a common VCC tolerance)  Bigger power wires to the Node to avoid IR losses

 

 

 

7 hours ago, robongar said:

If I had to take a guess, I don't think they will work. Have you tried them? However, being LED. I don't think the load will increase very much. I guess you could try wiring them in series.

Thanks.

The lights are some standard light strings I got really cheap the other day. This year, a new design of lights came about which uses only two wires to control two series.

Each LED is connected at alternate polarity.

The effects can be created be reversing the polarity, although this means that there is no true static effect.

 

Lights which will work on 30 volts are becoming rare and expensive.

 

I put the voltage up to 32. This is the voltage of the lowest voltage string (If this makes sense) I have 5 strings, 4 36v and 1 32v. 

Surprisingly, both sets I had connected worked great first time. There is a slight noticeable difference in the 36 volt string on my power supply compared to on its supplied one.

 

Thanks. It worked perfectly.

[TheDucks]

49 minutes ago, EmmienLightFan said:

 

 

Thanks.

The lights are some standard light strings I got really cheap the other day. This year, a new design of lights came about which uses only two wires to control two series.

Each LED is connected at alternate polarity.

The effects can be created be reversing the polarity, although this means that there is no true static effect.

 

Lights which will work on 30 volts are becoming rare and expensive.

 

I put the voltage up to 32. This is the voltage of the lowest voltage string (If this makes sense) I have 5 strings, 4 36v and 1 32v. 

Surprisingly, both sets I had connected worked great first time. There is a slight noticeable difference in the 36 volt string on my power supply compared to on its supplied one.

 

Thanks. It worked perfectly.

Old trick

Put 1 or more  Silicon Rectifier (diode) in series on the lowest voltage string to drop about  1 Volt for each in the series.. in your case ~ 4 rectifiers

the current rating and heat sink required for that strings draw