# Need some advise gor a diy reef led

#### Flozfzx

Joined Jan 15, 2018
8
Hi all new to this forum.

I am trying to build a fixture that has 24 leds at 3w most of the led are 3.2v-3.5v. Which will be two different channels so 12*3w each channel. There are reds in both channels that are 1.5v all the diodes have a max MA of 1000.

Im not sure if im correct but would i need a driver of 50w with output of 48vdc to drive one channel? So would i need 2? And would the red be effected because its 1.8v? @1000ma?

Please any feeds backs thank you.

#### dl324

Joined Mar 30, 2015
14,304
Welcome to AAC!

Thank you for trying to use good grammar.
I am trying to build a fixture that has 24 leds at 3w most of the led are 3.2v-3.5v. Which will be two different channels so 12*3w each channel. There are reds in both channels that are 1.5v all the diodes have a max MA of 1000.
Is the purpose of these LEDs to provide lighting for viewing or are they decorations?

Whether you can operate LEDs at their maximum current depends on power dissipation and how long they'll be on. LEDs can only operate at maximum dissipation for the temperature given in the datasheet, which is usually around 70C. Unfortunately, I've noticed that many datasheets don't give ΘJC (thermal resistance from junction to case) information. And you'd need to know ΘCA (thermal resistance from case to ambient) which is determined by your design.

If you care. The abbreviation for volts is V, the abbreviation of milliamp is mA, the abbreviation for watts is W. LED is an acronym and is written in all caps. Direct current is abbreviated DC.

#### Flozfzx

Joined Jan 15, 2018
8
Welcome to AAC!

Thank you for trying to use good grammar.
Is the purpose of these LEDs to provide lighting for viewing or are they decorations?

Whether you can operate LEDs at their maximum current depends on power dissipation and how long they'll be on. LEDs can only operate at maximum dissipation for the temperature given in the datasheet, which is usually around 70C. Unfortunately, I've noticed that many datasheets don't give ΘJC (thermal resistance from junction to case) information. And you'd need to know ΘCA (thermal resistance from case to ambient) which is determined by your design.

If you care. The abbreviation for volts is V, the abbreviation of milliamp is mA, the abbreviation for watts is W. LED is an acronym and is written in all caps. Direct current is abbreviated DC.
I have a heatsink but my question was, will a 50W 48dc mA1000 work for the project i'm working on?

#### dl324

Joined Mar 30, 2015
14,304
I have a heatsink but my question was, will a 50W 48dc mA1000 work for the project i'm working on?

You have two channels of nominal LED power of 36W. That's a maybe. Still need to know how much power the current limiting circuitry will consume.

#### philba

Joined Aug 17, 2017
959
Watts are fine, current not so much. Is your PSU a constant current or constant voltage type? 48V makes me think it's CV. How are you limiting current? Do you have links to the LEDs and PSUs?

#### whitehaired novice

Joined Jul 15, 2017
289
How many red LEDs are you using and are they 1.5 volts or 1.8 (you use both figures.)

Most LED suppliers sell drivers to suit normal configurations. That is going to need a BID heat sink.

If I may ask, are you growing coral?

#### Flozfzx

Joined Jan 15, 2018
8
Watts are fine, current not so much. Is your PSU a constant current or constant voltage type? 48V makes me think it's CV. How are you limiting current? Do you have links to the LEDs and PSUs?
Sorry its constant current 50W 48dc for 12 led at 3Watt each.

#### Flozfzx

Joined Jan 15, 2018
8
How many red LEDs are you using and are they 1.5 volts or 1.8 (you use both figures.)

Most LED suppliers sell drivers to suit normal configurations. That is going to need a BID heat sink.

If I may ask, are you growing coral?
Yes