QB304 Board Guide


Designed by Horticulture Lighting Group

High efficiency boards designed for Horticulture Lighting projects. Boards can be powered from 10 to 150 watts. Ideal for use in grow tents or grow area with reflective walls and grow spaces with limited height. No Thermal Interface Material is required between the QB304 board and flat metal heatsink.


  • 304pcs Samsung 561C top bin Diodes
  • Connectors rated 300V 9A
  • Estimated LER 321.60 lm/W
  • Estimated QER 4.86 µmol/J
  • Dimensions 6.833" x 11.25
  • Max current per board 1400mA


Flux Characteristics with 3000K, S6 Bin at 55C

Voltage  VDC Current (mA)

Watts at Board

 Lm/W at Board (55C) μmoles/joule at Board(55C)
101.46 350 35.51 190.7 2.83
102.98 500 51.49 184.5 2.74
104.88 700 73.41 177.6 2.64
107.92 1050 113.31 167.3 2.48
110.2 1400 154.28 158.8 2.36


  • Allow tolerance of an additional 2V while matching drivers.
  • Please use this as a reference only.

May require an Aluminum plate or heatsink if running 50+ watts. Heastink requirements depends on application and power.

The notes below are provided as a designs ideas and are not instructions to assemble a lamp. Do not touch live boards as they run on high voltage and may have exposed solder contacts that can cause serious shock. This is not a safety guide.


While using multiple boards, series wiring is preferable to avoid thermal runaway if a board gets disconnected.


Popular Drivers


Driver Notes (Single and Multiple Parallel Boards)

Non Dimmable


Parallel Wiring

Multiple Boards can be wired in parallel. Different batches of boards may have slightly different voltages. Use only boards from same batch for parallel connection. Do not use different spectrum boards in parallel as they may have slightly different voltages

Parallel LED Boards 

Driver Notes ( 2 Boards Series)

Non Dimmable


Series Wiring

Maximum 2 Boards can be wired in series. More than 2 boards in series will exceed the recommended maximum voltage of the board connectors and is not recommended.

 Series LED Connection

NOTE: Boards purchased in multiple orders may be from different batches may have different voltages and may not work share equal current if connected in parallel. Use them in series to avoid some boards pulling more current than others.

Parallel-Series Wiring (Advanced)

It is possible to have partial benefits of parallel and series together using some driver configurations. For example HLG-320H-C2800 can be used to power 4 boards in parallel and an alternate could be HLG-320H-C1400 with 2 parallel string of 2 boards in series.

 Series and Parallel LED Connection