Please don't get mad, I did look at other posts they touch the subject indeed by they are not answering my question and I have spent many hours so far on this already.
I'm posting here because I think my electrical understanding is incorrect and that costed me already enough time and frustration.
I have two questions, and they might seem trivial to you.
Question 1
Why is my old LED array dying, what did I do wrong?
I used a 12V at 1A power supply, to power 62LEDs (I think, I can double check at home).
It's a mixture of RED and BLUE LEDs.
12x BLUE LEDs: FORWARD VOLTAGE 3.0 - 3.2V ;MAX CURRENT 20 mA, wired in series of 3, 4 series.
60x RED LEDs: FORWARD VOLTAGE 2.0V ; MAX CURRENT 20 mA, wired in series of 5, so 8 series.
All series have one 1 Ohm resistor at the end, each.
To design the array I used : http://led.linear1.org/led.wiz
I think I should have used a 120Ohm resistor for the BLUE LEDs...is that what killed my array?
They started failing one serie after another...now I only have a few of BLUE about 3-4 series left...
I spent a full day soldering on this array, my lemon plants are doing great, I have a rose plant that seems to survive (give the roses to your wife when they are spent, cut the flower, leave 4-5 leafs, chip the bark, dip in routing hormone and you might get a rose),the dill and parsley are doing great too. It's all in a small printer box, a bit crowded but it works.
So imagine my frustration now when they will all die.
Question 2
I just ordered 10x High Power Led Helixeon Emitter 1W Blue 24lm,350mA, forward voltage min 2.35V,max 2.65V
and 5x High Power Led Helixeon Emitter 1W Red 55lm,350mA, forward voltage min 3.25V,max 3.55V
I have 2x 12V at 1A I can use and 2x 18.5V at 3.5A (old laptop power supplies)
How do I wire them?
I discovered http://ledcalc.com/# that seems to give more accurate and detailed results.
Could the 12V supply handle al 15 LEDs? I think not...
If I type in Supply Voltage 12V; Voltage Drop Across LED 2.35V (for the RED ones), Desired LED Current 350mA; and 10 LEDs , it designs an array with 2 series, using 1 Ohm resitors for the series.
BUT the Actual Single LED Current is 250mA, not 350mA , it said below...
Is that normal/safe?
I did something similar for the 5 Blue LEDs; I typed in Supply Voltage 12V; Voltage Drop Across LED 3.25V (for the BLUE ones), Desired LED Current 350mA; and 5 LEDs , it designs an array with 1 serie, using a 6.8 Ohm resitors for the serie.
Actual Single LED Current 330.9mA, again...not 350mA
Doing it for 15 LEDs will show Circuit's total current consumption 1654.4mA, so my 12V power supply can't handle 15 LEDs since it give a maximum 1A.
Also, as far as I know it should work at 80% capacity, so 800mA should be the maximum....
so no go on 12v I guess
would a 18v at 3.5A be able to do it? The calculator it's saying yes...
Can I wire all LEDs, red and blue to the power supply?
Using the calculator I tend to think yes but not sure if it will be safe for my array:
- one serie of 7 RED LEDs, using a 6.8 Ohm resistor; ( Actual Single LED Current 301.5mA - that worries me a bit, it's low...is it ok? )
- one serie of 3 RED LEDs, using a 33 Ohm resistor (Actual Single LED Current 347mA - that worries me a bit, it's to high!!! will it burn my LEDs ??)
- one serie of 5 LEDs using a 6.8 Ohm resistor
So again...a mixed array, and I have mixed feelings...
I tried to give as much info as I could, maybe to much...
I have a feeling I'm missing something, possibly something important...
I just spent 22£ on the 15 LEDs, I don't want to kill them and waste my time again...
Help!
I'm posting here because I think my electrical understanding is incorrect and that costed me already enough time and frustration.
I have two questions, and they might seem trivial to you.
Question 1
Why is my old LED array dying, what did I do wrong?
I used a 12V at 1A power supply, to power 62LEDs (I think, I can double check at home).
It's a mixture of RED and BLUE LEDs.
12x BLUE LEDs: FORWARD VOLTAGE 3.0 - 3.2V ;MAX CURRENT 20 mA, wired in series of 3, 4 series.
60x RED LEDs: FORWARD VOLTAGE 2.0V ; MAX CURRENT 20 mA, wired in series of 5, so 8 series.
All series have one 1 Ohm resistor at the end, each.
To design the array I used : http://led.linear1.org/led.wiz
I think I should have used a 120Ohm resistor for the BLUE LEDs...is that what killed my array?
They started failing one serie after another...now I only have a few of BLUE about 3-4 series left...
I spent a full day soldering on this array, my lemon plants are doing great, I have a rose plant that seems to survive (give the roses to your wife when they are spent, cut the flower, leave 4-5 leafs, chip the bark, dip in routing hormone and you might get a rose),the dill and parsley are doing great too. It's all in a small printer box, a bit crowded but it works.
So imagine my frustration now when they will all die.
Question 2
I just ordered 10x High Power Led Helixeon Emitter 1W Blue 24lm,350mA, forward voltage min 2.35V,max 2.65V
and 5x High Power Led Helixeon Emitter 1W Red 55lm,350mA, forward voltage min 3.25V,max 3.55V
I have 2x 12V at 1A I can use and 2x 18.5V at 3.5A (old laptop power supplies)
How do I wire them?
I discovered http://ledcalc.com/# that seems to give more accurate and detailed results.
Could the 12V supply handle al 15 LEDs? I think not...
If I type in Supply Voltage 12V; Voltage Drop Across LED 2.35V (for the RED ones), Desired LED Current 350mA; and 10 LEDs , it designs an array with 2 series, using 1 Ohm resitors for the series.
BUT the Actual Single LED Current is 250mA, not 350mA , it said below...
Is that normal/safe?
I did something similar for the 5 Blue LEDs; I typed in Supply Voltage 12V; Voltage Drop Across LED 3.25V (for the BLUE ones), Desired LED Current 350mA; and 5 LEDs , it designs an array with 1 serie, using a 6.8 Ohm resitors for the serie.
Actual Single LED Current 330.9mA, again...not 350mA
Doing it for 15 LEDs will show Circuit's total current consumption 1654.4mA, so my 12V power supply can't handle 15 LEDs since it give a maximum 1A.
Also, as far as I know it should work at 80% capacity, so 800mA should be the maximum....
so no go on 12v I guess
would a 18v at 3.5A be able to do it? The calculator it's saying yes...
Can I wire all LEDs, red and blue to the power supply?
Using the calculator I tend to think yes but not sure if it will be safe for my array:
- one serie of 7 RED LEDs, using a 6.8 Ohm resistor; ( Actual Single LED Current 301.5mA - that worries me a bit, it's low...is it ok? )
- one serie of 3 RED LEDs, using a 33 Ohm resistor (Actual Single LED Current 347mA - that worries me a bit, it's to high!!! will it burn my LEDs ??)
- one serie of 5 LEDs using a 6.8 Ohm resistor
So again...a mixed array, and I have mixed feelings...
I tried to give as much info as I could, maybe to much...
I have a feeling I'm missing something, possibly something important...
I just spent 22£ on the 15 LEDs, I don't want to kill them and waste my time again...
Help!