Keep it Constant: Constant Voltage Tips and FAQs

Constant Voltage luminaires require a Constant Voltage power supply e.g. 48V, 24V or 12V. For Constant Voltage lighting the “voltage” remains the same but the “current” varies depending on the load.  

Key Installation Tip: Constant Voltage luminaires must be wired in parallel.

The current required from a Constant Voltage driver increases with the number of lights. For example, three luminaires will draw three times as much current as a single luminaire.

Output Power [W]

When choosing a driver the total output power of the lights must be taken into account. Constant Voltage drivers have a maximum output wattage, you must stay under this parameter for optimal performance and Driver lifespan.

Output Current [A]

When choosing a Constant Voltage LED driver you must observe the current requirements of your light source/s to ensure you are using a big enough driver (see example). A common sign that your circuit exceeds the maximum output current of your chosen driver is flashing / strobing lighting.

Output Voltage [V]

For constant voltage, the DC output voltage of the Driver must meet the LED requirements. e.g. 24V requires a 24V Driver.

Constant Voltage: Typical Applications

• LED Linear Strip light (LED Tape)

• Remote Driven Exterior lighting e.g. Exterior ingrounds or spike spots

Constant Voltage Common Example: Remote driven 24V exterior lighting

Imagine a customer requires 10 x EX105 3W Constant Voltage exterior spike spots powered from a single 24V DC Driver. The total circuit wattage equals 30W.

Do you choose option 1 or option 2?

Option 1: Halcyon 40W 24V Driver (output current 0 – 1.67A)

Option 2: Halcyon 75W 24V Driver (output current 0 – 3.0A)

Answer: Option 2 – Driver selection must take into account the max wattage/amperage of the driver vs the number of lights of the circuit and start up / inrush current required by each light. For long runs voltage drop must also be taken into account.

In this case the total current draw of the 10 x EX105 3W spike spots would exceed the output current parameters of the 40W driver (Option 1) resulting in flickering or flashing lighting. This is due to the inrush current from the 10 connected EX105’s momentarily exceeding the drivers maximum current rating.

If in doubt always use a bigger than necessary Constant Voltage driver to ensure output current is covered. Calculate the total load of the circuit and find a Halcyon Constant Voltage driver double the load or greater.

Tip: If you are wiring a 12V constant voltage luminaire to a battery circuit, you need to run a DC/DC driver to regulate voltage supply. When under charge a battery system voltage can increase significantly which would damage the luminaire if the circuit was not regulated to a constant voltage output.

Common Troubleshooting

1. When the circuit is powered on, all connected lighting flashes on and off together.

Check size of driver, Halcyon drivers have an overload protection which will cause the circuit to flash on and off when exceeded.

2. When the circuit is powered on, only half the connected lighting flashes on and off together. The rest does not work.

Check for wiring fault, Halcyon drivers have an automatic fault detect and reset function. Flashing on and off could indicate the driver has detected a fault e.g. short circuit and is repeatedly trying to reset itself.

3. When the circuit is powered on, the fittings at the end are flickering and dim.

Check run length and cable type. 1.5mm cable is sufficient for most 24V exterior lighting circuits.