I was making a LED string using parallel config and I want know if my string will have power balancing issues. I'm using a 12 meter wire (24 AWG Aluminium stranded wire) and having 50 LEDs at parallel, 20cm apart. 470 ohms for each with LEDs and power supply is at 12v 1amp.
A lot of people told me that the LEDs will not be balanced and that the LEDs closer to the power supply will be brighter and the farther LEDs will be dimmer. They say that I'll have to use another cathode wire from the farthest LEDs ground and bypass it to the power supply's ground. Like shown at figure B. Do I have really have that second ground wire?. Does Figure A has bad balance issues?
I would think that the voltage drop across such thin aluminum wire would be considerable over a length of 1 metre. Have you measured it ? Why the need for the wire to be so thin and how are you going to make the connections to it ?
Why have you used this circuit? It is highly inefficient. The battery will provide 12W power but only 2.4W will be consumed by the LEDs. The other 9.6W will be wasted as heat by the resistors. That is only 20% efficient.
If you connected groups of 4 LEDs in series and used a 120R resistor for each group, you would have almost 80% efficiency.
This would also dramatically increase your battery life and reduce the current in the anode and cathode wires from 1A to only 0.26A. This would reduce the voltage drop in those wires, which would greatly reduce the power balancing problem.
Placing the LEDs in series in say groups of about 5 (depends on color) will reduce your current requirements and the power wasted in the current limiting resistor.
I understand the concern about efficiency but my point is that will I need that extra wires. I'm only concern about the LEDs getting dimmer along the string.
