FAQ Drivers - Difference between Series and Parallel Wiring

It is important to understand the difference between SERIES and PARALLEL wiring when connecting LED lights to their drivers.  In most case there is a single light for a single driver so this article does not matter so much as the connection between a single light and the single driver is easy, simply connect the positive (Red) wire in the LED to the positive output on the driver and the same goes for the black negative wire.

This article is more important for connection of multiple LED lights to a single transformer.  When wiring multiple LED lights together failure to get the connection correct will more than likely result in failure of the LED lights themselves, One light may fail or all of the lights fail.

There are two types of Drivers for LED Lights

Constant Voltage:

Constant volatge drivers will deliver a specific stable voltage - ie 12 Volt DC, no matter what the load is this driver is designed to deliver the 12 volts at all times.  Constant Voltage drivers will always be wired in parallel, check the diagram below for an example of parallel wiring.  Parallel wiring will ensure that each light connected on the circuit will recieve the same 12 volts that the driver is designed to deliver.  Each light connected will receive 12volts but the current will vary depending on the type of LED connected.  So to sum it up, these drivers produce a constant 12 volts but he current is designed to vary. 

Constant Current:

Constant current drivers as the name suggest deliver a specific amount of current, typically 300milliamps or 700milliamps to the LED, It is very important that each LED on the circuit receives the same current so constant current drivers will always require the lights be wired in SERIES.  SERIES wiring makes sure each light receives the nominated current (300milliamps) but in this case the voltage is not always the same, it is the opposite to constant voltage type drivers and the voltage can vary up and down depending on the load connected.

Special notes on Constant Current.

  1. If a SERIES wired constant current LED is accidently wired in Parallel, the LED will more than likely fail. Be sure to check the wiring before connecting.
  2. LED lights connected on a Constant current driver can  NOT be connected and disconnected while the power to the driver is still on, the LED's will fail.  Added to that if a driver is powered up without a load then switched off, the internal capacitors can still hold a charge for approximately 30mins, connecting an LED with the capacitors charged will also result in the LED failing.  The output of the driver needs to be short circuited to discharge the drivers before an LED should be connected.

Series and Parallel