LED Driver (electrical help)

[jbdreefs]

So... it looks like one of my LED drivers quit :boo:

I'm looking for replacements. I obviously, don't want to go with the brand of driver that I purchased for the first go-around, so i'm shopping for a replacement. I do not want to significantly overhaul my wiring which is setup using strands of 18 LEDs. I'm currently using a driver to power 18 LEDs that outputs upto 70V @ 680ma.

Apparently, the MeanWell LPF-90D-48 can handle this load because it is an option (now available) for the LED package I bought. It is able to run 36 3w LEDs. I should be able to replace two of my drivers with one of these, but I have some questions. Here are the specs on the MeanWell driver: Output voltage is upto 48V DC @ 1.88A. Rated for 90 watts.

As suggested, I would wire the LEDs in 3 strands of 12, wired in parallel. I'm assuming that by doing this, I would drop the amperage to 627 ma (1.88/3). Can anyone confirm that my math is appropriate/correct? Does anyone know for sure if the lights will be less bright because of the lower amperage? Does anyone know if I can cheat the meanwell driver by adjusting it "up" to achieve a final amperage of 680ma?

Finally, if anyone knows of a better solution, please share. Thanks!

 

[johniii]

P=I/R
P is potential or voltage
I=current
R=resistance
PxI=watts

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[johniii]

JohnIII;750597 wrote: P=I/R
P is potential or voltage
I=current
R=resistance
PxI=watts

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Some people use an E instead of P for voltage

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[johniii]

What is the rated voltage of your led chips and the rated wattage?

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[jbdreefs]

JohnIII;750625 wrote: What is the rated voltage of your led chips and the rated wattage?

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Max is 3.6V @ 700ma = 2.52w

 

[johniii]

When I get home ill draw it out.

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[jbdreefs]

that would be awesome, thanks!

 

[johniii]

From what I see in the numbers you will need 12 parallel strands with 3 in series on each strand which will bring your toward voltage to 3.11v. Which is going to bring you to about 2 watts a piece.

Someone chime in if I miscalculated

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[jbdreefs]

The seller recommends 3 strands of 12 which is, oddly, the inverse of what you are suggesting.

 

[johniii]

In a series circuit voltage is reduce. @ 48 volts you would need 13.3 ohms to get 3.6v. Your less are 5.14 ohms a piece. Three in series gives you 15.42 ohms. 48v÷15.42ohms=3.11v. If you had 12 in series your voltage would drop to .71volts. Just thought I would post how I got the numbers I got.

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[jbdreefs]

Thanks!

 

[johniii]

JBDreefs;750669 wrote: Thanks!

You are welcome.

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