Grow light ballast
What Does A Grow Light Ballasts Do?
A ballast is needed for the majority of grow lights.
The ballast is built into fluorescent lights, while LED lights do not.
However, if you want to use HID plant lights, you would need to purchase the ballast separately.
The easiest way to accomplish this is to purchase an HID grow light package that includes all you need (MH bulb, HPS bulb, ballast, reflector, hangers, and timer), but if you already have any of those items, you can purchase the ballast separately.
In any case, you're going to need one.
But why do you need one?
What exactly does a grow light ballast do?
What Is A Grow Light Ballasts And What Does It Do?
In a nutshell, ballasts control light bulbs.
When they are burning, grow lamps have a low resistance, but they need a high voltage to start. Both are provided by a ballast.
When you switch on a light, the ballast provides a high enough voltage to start the arc (for more on HID bulbs and how they work, see this article). The sodium is solid when the arc first strikes, but it soon melts and vaporizes.
Diagram of ballasts and bulb
The resistance of the lamp decreases in the gaseous state, and it takes much less power to keep working. The ballast ensures that the lamp only receives the current it needs.
Without the ballast to control the amount of electricity entering the lamp, the light will continue to intensify until the bulb blew.
When the HID bulb first turns on, it takes more power than your outlet provides, so the ballast increases the amount of power it receives from the wall to provide the lamp with what it needs to light up. If it's turned on, it controls whatever power it gets from the wall (which can vary) and ensures the lamp still has a constant supply of electricity.
HID bulbs actually need more power to operate as they age. As the bulb ages, the ballast automatically increases the amount of power delivered to it.
When the bulb requires too much fuel, the ballast shuts it down to avoid an accident. You can restart the bulb in this situation, but the ballast will easily shut it down again. This means it's time to replace the light bulb.
Ballasts are classified into two types: magnetic and electronic.
Magnetic Vs Electronic Ballasts
Both have advantages and drawbacks, but electronic ballasts are preferable for the majority of us. They are more powerful and run hotter (higher output while using less power). Most are dimmable (can run lower wattage bulbs as well) and can run both HPS and MH bulbs.
They do, however, have drawbacks, and they are not the perfect option for all. Continue reading to find out which ballast is right for you.
What Is Magnetic Ballasts and How Does It Work?
Magnetic ballasts are made up of a wide spool of wire wrapped around steel sheets. This generator generates the high voltage needed to power an HID bulb. To control the electricity, they use a canister made of plastic or metal.
Magnetic ballasts are outdated and have fallen out of favor. They are large and produce a lot of heat.
They do, however, have some advantages. They are tough and usually last much longer than electronic ballasts, running for years even in adverse conditions.
More importantly, they are designed to ANSI (American National Standards Institute) standards, ensuring that the lamp and ballast work properly together.
The issue is that metal halide and high-pressure sodium have different specifications, necessitating the use of separate ballasts. There are switchable magnetic ballasts that can operate both types of bulbs, but they are constructed to HPS standards and thus are not specifically designed to run MH bulbs, though they can.
Electronic ballasts, rather than magnetic coil, use semiconductors and microchips to provide the high voltage provided by HID lamps. As a result, the interior of an electronic ballast resembles a device rather than what you would imagine a ballast to look like.
Since they lack the heavy coil, they are much smaller and lighter than magnetic ballasts. They also work much more quietly.
The key disadvantage of electronic ballast is that no ANSI specification exists for its compatibility with HPS and MH lamps, at least not for high-wattage (250+ watts) models. As a consequence, they are all made differently, resulting in inconsistencies in bulb efficiency.
This is another reason why we usually advise purchasing a full lighting system. That way, you'll get a ballast built to power the included bulbs.
On the positive side, almost all electronic ballasts are switchable, which means they can safely run both metal-halide and high-pressure sodium bulbs. Most are now dimmable, allowing you to operate several wattages of bulbs. It does not necessarily imply that you can dim the ballast in order to run a lamp at less than full capacity.
Ceramic metal halide lamps, on the other hand, do not fall into this category. They necessitate the use of special ballasts with a much lower frequency. Again, simply buy a pack.
What Is A Digital Ballast Grow Light?
Electronic ballasts are often known as "digital ballasts," but very few are.
A ballast is only digital if it has a microprocessor. The majority of “digital” ballasts do not.
Does LED Grow Lights Need A Ballast?
LED grow lights do not need a ballast. There are no extra components to purchase since the fixture includes everything you need.
If you have an existing T5 fluorescent fixture and want to replace the fluorescent bulbs with T5 LED grow light tubes, you may need to bypass the fixture's ballast. Some LED tubes operate with the ballast, but many need it to be disconnected in order to function.
What Is the Role of a Grow Light Ballast: Final Thoughts
As you can see, grow light ballasts perform a vital function and you can not operate an HID lighting system without one. Luckily, they are always included in plant light kits, so you don’t generally have to worry about finding one that is compatible with your reflector and bulbs.
Of course, you can make your life much easier by simply using LED lights instead. These days, they are much more efficient and prices have come down so much that they do not cost much more either. They will easily pay for themselves within a year, due to the cost savings of using less power, generating less heat, and not having to change bulbs