Hi, I tend to use an online calculator any time I want to design an LED array, so I have no idea, really...
I mean, I recently wanted a 28 LED array, running off a 6 volt battery, so I used the online calculator. I then tried the same led specs and number of LEDs with 12v just in case I changed my mind.
Instead of 7 parallel rows of 4 LEDS, this time the calculator suggested 4 parallel rows of 7. (I think the resistor values were pretty much the same) I noticed that the 12v array was drawing much less current. What the hell? Surely it should be the same or thereabouts? Surely the array can't draw half the current and still be as bright?
These online calculators spit out all sorts of numbers, like current drawn by the array, power dissipated by the LEDs, and by the resistors...etc. So, which numbers do I need to be looking at to design an array that is as efficient as possible? I was under the impression that getting the array to work out so that it had the lowest value resistors possible would be more efficient, but someone pointed out that that isn't really the case. (Though I think that was more of a safety issue, or maybe to do with how the battery voltage drops as the battery dies)
Is there even a "smarter" online calculator that can give reasons why one solution is better than another? I mean, the math is simple enough that a computer should be able to do it. (and I truly HATE math)
Oh, and the forward current they ask for...is that the MAX forward current as per the data sheet, or is that the current you WANT each LED to see in the finished array?
I mean, I recently wanted a 28 LED array, running off a 6 volt battery, so I used the online calculator. I then tried the same led specs and number of LEDs with 12v just in case I changed my mind.
Instead of 7 parallel rows of 4 LEDS, this time the calculator suggested 4 parallel rows of 7. (I think the resistor values were pretty much the same) I noticed that the 12v array was drawing much less current. What the hell? Surely it should be the same or thereabouts? Surely the array can't draw half the current and still be as bright?
These online calculators spit out all sorts of numbers, like current drawn by the array, power dissipated by the LEDs, and by the resistors...etc. So, which numbers do I need to be looking at to design an array that is as efficient as possible? I was under the impression that getting the array to work out so that it had the lowest value resistors possible would be more efficient, but someone pointed out that that isn't really the case. (Though I think that was more of a safety issue, or maybe to do with how the battery voltage drops as the battery dies)
Is there even a "smarter" online calculator that can give reasons why one solution is better than another? I mean, the math is simple enough that a computer should be able to do it. (and I truly HATE math)
Oh, and the forward current they ask for...is that the MAX forward current as per the data sheet, or is that the current you WANT each LED to see in the finished array?