Yes, I know. I am keeping the strings in the 3V range, that's the only way I can be sure it works. I did some measurements (A and V) from 0 to 20 steps (every channel goes up to 24 steps if I remember correctly), and around step 17 I got around 700mA (I don't remember the voltage, I must have it on a paper somewhere). I have some electronics experience and I am trying to keep my power supplies, drivers and LEDs safe
. The red LEDs are opening up a bit quicker, so I will have to put probably 4 of them in series. I will make some measurements and maybe I will use some resistors so I can max out the drive (step 24 on the remote) without killing it or the LEDs.
I will have to go with the drive I have for now, but as you say, I envision using constant current, pwm controllable drivers in the future, controlled by an Arduino, together with other aquarium functions. I do have plans for the future, but for now I want to deal with what I have.
your missing a minor point. The "dimmer" doesn't change current.. it only pulses it. It may average to 700mA but it is feeding all it can to the LEd's...
At least this is how the more common "strip" devices work..
W/out th current limiting resistors all you are doing is pulsing 2A.. or whatever your PS can put out if you are not exceeding the V(f) requirement.. and you won't w/ 3 or less LED's..
In other words it is like 2A w/ a 50% duty cycle averaging to 1A over time.
As an example w/ "real world" LED's.. This is a circuit for a Cree xp-e using a 12v constant voltage power supply. Your PS could only run 2 3 diode series strings in parallel and you will max out the 2A ps..
The resistors function is to drop the 12v to 10.5V....which is the voltage that creates the 1000mA "draw"..
you will need a 1.5Ohm 1.5W resistor for every 3 LED's and 1A per every "set" of three run in parallel....
Yes by limiting your pulse width (duty cycle) to under full out you can control it.. but not very elegantly..
Figure 2: Internally generated PWM signal and LED current for the application in Figure 1
The amplitude doesn't change (1A).......... only the period.. which is how most of these dimmers work.. Cutting into the cycle
The V(dim) is just the signal.. not the drive current or voltage..
without knowing your exact "dimmer" and its inner workings I can't 100% guarantee the above is correct.. but I'm fairly confident that this is how it works..
Overloading the ps is a way to control the current..
regarding "deep red" and using Luxeons as an example:
Forward Voltage is 2.20V @ 350ma, 2.3V @700ma