do it yourself aquarium light

Thread Starter

rickv073

Joined Oct 7, 2021
26
hi,

i'm new here and also (kinda) new to electronics.
i'm working on my own aquarium led fixture, i have all the components (for as far i know for now) except for the led driver.
i need some help figuring out what led driver i need to use, and what the best way is to connect all the leds.

i have added a simple picture of where all the different colored leds will be.
all the leds are 1W high power leds, they need 350mha of current and around 3.3V (voltage can vary a little bit between the colors)
i have around 100 leds that i need to power. i want to control the re green and blue channel with a potentiometer and the other colors to but they are 1 channel.

is there someone that can help me figure this out?
i think it is an pretty easy question for people that know how leds and led drivers work, but for me this is just a bit to complicated.

many thanks in advance!!!!
kleur combinatie.png
 

dl324

Joined Mar 30, 2015
13,490
Welcome to AAC!
is there someone that can help me figure this out?
You haven't provided enough information.

You say the LEDs need 350mA (note the corrected units) with an approximate forward voltage. How do you plan to wire them? What supply voltage is available?

i want to control the re green and blue channel with a potentiometer and the other colors to but they are 1 channel
That will be more complicated than you think. There aren't many potentiometers that will take that much current, so you're going to need some other circuit to control on/off time for the LEDs. If you want to vary the brightness independently, that's 3 times the circuitry.
 

Thread Starter

rickv073

Joined Oct 7, 2021
26
Welcome to AAC!
You haven't provided enough information.

You say the LEDs need 350mA (note the corrected units) with an approximate forward voltage. How do you plan to wire them? What supply voltage is available?

That will be more complicated than you think. There aren't many potentiometers that will take that much current, so you're going to need some other circuit to control on/off time for the LEDs. If you want to vary the brightness independently, that's 3 times the circuitry.
i want to wire them in series and parallel to match with the output of the led driver.

what exactly do you mean with: what supply voltage is available?

i use the red, green, blue, full spectrum, cyan and uv diodes.

1633642915532.png
 

dl324

Joined Mar 30, 2015
13,490
i want to wire them in series and parallel to match with the output of the led driver.
An LED driver drives a series string of LEDs at the same current. If you want to control brightness of strings individually, you need a way to turn them off and on at a duty cycle that gives the desired brightness; by connecting and disconnecting the LED driver because the drivers are constant current sources.
what exactly do you mean with: what supply voltage is available?
How are you going to power the LED drivers? I assume you want to build your own.
 

Thread Starter

rickv073

Joined Oct 7, 2021
26
An LED driver drives a series string of LEDs at the same current. If you want to control brightness of strings individually, you need a way to turn them off and on at a duty cycle that gives the desired brightness; by connecting and disconnecting the LED driver because the drivers are constant current sources.
How are you going to power the LED drivers? I assume you want to build your own.
No I want to buy one actually
I have tested a potentiometer with a small led driver I have and that worked ‍♂
 

Thread Starter

rickv073

Joined Oct 7, 2021
26
An LED driver drives a series string of LEDs at the same current. If you want to control brightness of strings individually, you need a way to turn them off and on at a duty cycle that gives the desired brightness; by connecting and disconnecting the LED driver because the drivers are constant current sources.
How are you going to power the LED drivers? I assume you want to build your own.
Or is it better if I build one myself?
 

Danko

Joined Nov 22, 2017
1,178
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Juhahoo

Joined Jun 3, 2019
249
You have 6 different colors, use 6 different constant current LED drivers, one for each color. Else it is impossible to adjust their brightness ratios. Every LED color produces different brightness level with same current therefore you need to be able to adjust them individually.
 

jiggermole

Joined Jul 29, 2016
48
I think Danko has the right way about it. Each color on its own dimmer. All of each color wired in series. And you don't have to do any circuit design, its all done already.
 

Thread Starter

rickv073

Joined Oct 7, 2021
26
Use dimmable drivers, by one for every channel. In each channel should be in series connected LEDs with summary voltage 60 - 80 V.
https://www.alibaba.com/product-det...3.html?spm=a2700.wholesale.0.0.329558d0YSuV7B

For each driver use separate dimmer:
https://www.alibaba.com/product-det...1.html?spm=a2700.wholesale.0.0.576e3b87V8urn5
I have one more question. The drivers that you linked are 0-10v, how does it work if I connect the leds with the same color in series to this driver? The 10v is reached in less then 4 leds right? Or is the 0-10v for the dimming feature? (Probably a stupid question but I’m new to all of this stuff)
 

Danko

Joined Nov 22, 2017
1,178
I have one more question. The drivers that you linked are 0-10v, how does it work if I connect the leds with the same color in series to this driver? The 10v is reached in less then 4 leds right? Or is the 0-10v for the dimming feature? (Probably a stupid question but I’m new to all of this stuff)
Dimmer provides control voltage from 0VDC to 10VDC, depends on knob angle rotation.
Driver contains PWMed 300mA current source, working at frequency about 2kHz and controlled by voltage from dimmer.
So, when control voltage changes from 0 to 10V, then PWM duty cycle of current 300mA changes from 0 to 100%.
2021.10.08 18-18-40.png
 
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Thread Starter

rickv073

Joined Oct 7, 2021
26
Dimmer provides control voltage from 0VDC to 10VDC, depends on knob angle rotation.
Driver contains PWMed 300mA current source, working at frequency about 2kHz and controlled by voltage from dimmer.
So, when control voltage changes from 0 to 10V, then PWM duty cycle of current 300mA changes from 0 to 100%.
View attachment 249822
Ok I get it!
and for the UV diodes I don’t have enough of them to reach the 60-80v, will that be a problem with these drivers? Or can I connect leds up to 60-80 volts but isn’t it a problem if it is only 30v for example.
 

Danko

Joined Nov 22, 2017
1,178
Ok I get it!
and for the UV diodes I don’t have enough of them to reach the 60-80v, will that be a problem with these drivers? Or can I connect leds up to 60-80 volts but isn’t it a problem if it is only 30v for example.
Vx = 60V - 30V = 30V
Rx = 30V / 0.3A = 100Ω
Px = 30V * 0.3A = 9W
--------------------------
Connect 100Ω, 20W resistor in seires with UV LEDs.
 

dl324

Joined Mar 30, 2015
13,490
Or is it better if I build one myself?
Only if your intent is to learn how to do it, ready made solutions are too costly (and you think you can DIY for less), you have a custom application, you understand how to do it safely, etc.

I assumed that you meant build your own when you said DIY. Depending on how you configured the LEDs, that could result in some dangerously high voltages; especially if the end product is used near water.

The widely accepted "good" method for dimming LEDs is to use PWM. Varying the current won't usually give the desired behavior because the light emitted from LEDs isn't linear with current. PWM will turn them on and off at the driver's set current and vary the duty cycle to obtain the desired brightness.
 

Thread Starter

rickv073

Joined Oct 7, 2021
26

Thread Starter

rickv073

Joined Oct 7, 2021
26
Only if your intent is to learn how to do it, ready made solutions are too costly (and you think you can DIY for less), you have a custom application, you understand how to do it safely, etc.

I assumed that you meant build your own when you said DIY. Depending on how you configured the LEDs, that could result in some dangerously high voltages; especially if the end product is used near water.

The widely accepted "good" method for dimming LEDs is to use PWM. Varying the current won't usually give the desired behavior because the light emitted from LEDs isn't linear with current. PWM will turn them on and off at the driver's set current and vary the duty cycle to obtain the desired brightness.
I’m trying to build the light myself, I really want to learn more about electronics as long as I can do it safely….. and what you already mentioned high voltage near water….. and someone that is not 100% sure about what he is doing. I’m going the safe way by buying a driver, if this works out great I want to learn how to make one myself! But a smaller version.
 

dl324

Joined Mar 30, 2015
13,490
I’m going the safe way by buying a driver
Depending on how many LEDs you wire in series, you could still have lethal voltages present. You show a couple dozen red LEDs in your array; that would give you more than 75V.

50V is considered potentially lethal for humans. I don't know what it is for fish in an aquarium, but I suspect it will be less than 50V with water with impurities involved.

EDIT: added ly to potential
 
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