Why digital ballasts are best

Posted by GrowDave 24/09/2018 0 Comment(s)

Sometimes it’s not all about the yield


Every HID light needs a ballast. Typically you would buy your lights in a kit where the correct ballast and cables are included with the lamp you bought meaning everything matches up fine. 2 years down the line it is time to replace the ballast and now you face a decision. Do I go with a magnetic ballast or a digital one?

Most things in your home require a constant voltage to sun correctly. HID lighting needs a constant current to work correctly and efficiently. To get this constant current you need to use a ballast. This ballast ensure the lamp gets an uninterruped current that keleps things properly lit and long lasting.

There are two main types of ballast, magnetic and digital.



Inside a magnetic ballast the core is a mix of copper wire and iron wire. This is why a magnetic ballast weighs so much. This core maintains the current and generates the higher volatge required to light the HPS lamps.

Inside a digital ballast their are curcuit boards…


The good and bad

  • Magnetic ballasts last 5-10 years without much loss.
  • Digital ballasts typically need replacing after 3 years.
  • Magnetic ballasts waste about 8% of the energy on heat.
  • Digital ballasts are very efficient.
  • Magnetic ballasts have no built in safety features.
  • Digital ballasts will turn the lamp off when supply is poor and power back on automatically once the surge has passed.
  • Magnetic ballasts are cheap to buy,
  • Digital ballasts cost double a magnetic ballast typically.
  • Magnetic ballasts work with one rating only (250w, 400w OR 600w)
  • Digital ballasts have a range of power outputs.  (250w, 400w AND 600w)


We would normally advise a new grower to go for a good digital ballast as they pay for themselves over their life and they will give you better fail protection which is important if you don’t want your house burnt down! That said, the magnetic ballasts work fine for their price and are certainly a good piece of kit based on the limits above.



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