The project: Install 12VDC 3 Watt Low voltage LED pathway lights, one every 20', along a 420' boardwalk through a mangrove forest. There are 24 lights and to minimize taps in the main line they will be installed in groups of 3 with one light at the tap, one light 20 feet behind and one 20 feet ahead. Taps will be 60 feet apart.
I am assuming that the full 72 watt load in the first 60' will cause significantly more voltage drop that the 9 watts in the last 60' so I treated the setup as 7 separate segments and calculated the voltage drop for each segment with the input voltage being the reduced voltage from the previous segment and the wattage being what remains to be powered. Assuming this logic is correct, an input voltage of 13.8V and #8 AWG copper will result in voltage at the end of right at 12V. A total of 13% drop.
First question: Is my methodology reasonable?
Second, will the LED lights at the first tap be able to handle the 13.8V or do I need to add some resistance to bring the voltage down?
I am assuming that the full 72 watt load in the first 60' will cause significantly more voltage drop that the 9 watts in the last 60' so I treated the setup as 7 separate segments and calculated the voltage drop for each segment with the input voltage being the reduced voltage from the previous segment and the wattage being what remains to be powered. Assuming this logic is correct, an input voltage of 13.8V and #8 AWG copper will result in voltage at the end of right at 12V. A total of 13% drop.
First question: Is my methodology reasonable?
Second, will the LED lights at the first tap be able to handle the 13.8V or do I need to add some resistance to bring the voltage down?