How to Evaluate Driver Quality in LED Grow Lights

What a driver is in an LED grow light

A driver is the power supply of an LED grow light. It changes the voltage from a wall outlet into the steady current that the LED chips need. In listing terms, the driver appears as a brand name, a wattage draw, or a phrase such as "constant current" or "constant voltage". Plants need light for photosynthesis, and a grow light supplies that light when a window does not, as the University of Minnesota Extension explains.

Constant current and constant voltage describe how the driver feeds the LEDs. A constant current driver keeps the current steady while the voltage can vary; this is common in quantum boards and bar lights. A constant voltage driver keeps the voltage steady and is common in strips and flexible lights. Compare constant current and constant voltage drivers.

On a listing, the driver is not always named. The first words of the title usually name the light type and the wattage, and the driver brand, if any, appears later in the bullet list. A missing name is not a fault; the maker's page for the model often names the driver and its output.

Before any electrical work or mounting, follow the maker's manual and local electrical rules.

Efficiency as a maker term

Efficiency on a grow light listing is usually stated as efficacy, measured in micromoles per joule (umol/J). It describes how many photons the light produces for each joule of electrical energy it draws. A higher figure means more of the power becomes usable light.

The catalogue that this site compares from does not read efficiency figures, because sellers rarely state them in the listing title. You will find efficacy on the maker's own page for the model, in a spec sheet, or in the manual. Programs such as the DesignLights Consortium's horticultural list verify stated performance claims for qualified fixtures.

When you compare two listings, the stated watts are a fair starting point, but efficiency is a separate term. Understand what efficacy means and read how this site compares lights.

• Other efficiency words that may appear on a listing: photon efficacy, umol/J, power factor.

Lifespan and L70, L90

Lifespan on a grow light listing is usually stated in hours and often uses an L70 or L90 figure. L70 means the time at which the LED output declines to 70 percent of its initial value; L90 means 90 percent. These are standard ways to describe how long an LED stays near its original brightness.

Sellers rarely put L70 or L90 in the listing title. The maker's spec sheet and manual state the lifespan figure, and sometimes the warranty text does too. This site does not read lifespan figures, because they are not part of the stated details in the catalogue.

For a shopping decision, a driver that is dimmable or has a timer changes how many hours the light runs, so pairing the lifespan term with a control feature is useful. Read about warranty and lifespan and L70 vs L90.

Dimming controls on a listing

Dimming is a driver feature. A listing that says "dimmable" means the driver can lower or raise the power to the LEDs. The control method appears as a word on the listing: a dimmer knob, a dial, a remote, or an app.

Two dimming methods you may read are 0-10V and PWM. 0-10V dimming uses a low-voltage control signal, and PWM, which stands for pulse width modulation, switches the LEDs on and off rapidly to change perceived brightness. Both are descriptions of how the driver responds to a signal; you do not need to choose between them from a listing. Compare 0-10V and PWM dimming.

A dimmer can be built into the driver, or the light may come with a separate controller that connects to the driver. The listing words tell you which: "dimmer knob" and "dial" usually mean a control on the driver or the power cord, while "remote" and "app" mean a separate controller. Neither is better from a listing alone; read the manual for how the control works.

A built-in timer is a separate feature that controls when the light turns on and off, and it is often listed as cycles such as 4/8/12H or 3/9/12H. If a title states a timer, the light has a timing circuit inside or ships with a controller. Compare dimmable grow lights and timer options.

• Words that describe dimming on a listing: dimmer knob, dial, remote, app, 0-10V, PWM, stepped, linear.

Driver brand names on a listing

Some listings name the driver brand. Mean Well is a common name in grow light listings, and a phrase such as "Mean Well driver" tells you the maker chose a specific power supply for the model. Other listings say "driver included" without naming the brand.

A branded driver is a useful detail to compare, but the brand alone does not tell you the efficiency, the lifespan, or the dimming range of the light. Those numbers are on the maker's page. Compare Mean Well and generic drivers and read what a Mean Well driver is.

A listing may also state the pack size, such as 1, 2, 4, or 8 lights. The driver is part of each light, so the pack size does not change the driver quality of one light.

What the catalogue cannot tell you

This site's guides compare the stated details found in listing titles: light type, watts, coverage area, chip maker, dimmable, timer, and brand. Driver efficiency, lifespan hours, heat, and noise are not in that pool.

When you want those numbers, read the listing's bullet list first, then the maker's page and the manual for the exact model. The Vivosun site and the GE lighting site are examples of where a maker presents its own product pages. Browse the best VIVOSUN grow lights and the best LED grow light panels.

What to pick for your job

Questions

What is a driver in an LED grow light?

A driver is the power supply that feeds the LEDs. It converts wall voltage into the steady current the LED chips need. In listing terms it appears as a brand name, a wattage draw, or a phrase such as constant current or constant voltage.

How do I compare driver efficiency on a listing?

Efficiency is usually not in the listing title. Read the maker's spec sheet or manual for efficacy, which is measured in umol/J. The DesignLights Consortium verifies stated performance claims for qualified horticultural fixtures.

What do L70 and L90 mean?

L70 and L90 are lifespan terms. L70 means the time at which LED output declines to 70 percent of its initial value; L90 means 90 percent. The maker states the hours on its own page.

Does a branded driver mean a better light?

A driver brand such as Mean Well is a useful detail, but the brand alone does not state efficiency, lifespan, or dimming range. Read the maker's page for those numbers.

Can every driver be dimmed?

No. A listing must state "dimmable" for the light to have dimming. If the word is missing, the light likely turns on and off only.

Where do I find the driver details for a light?

Check the listing's bullet list, then the maker's page for the exact model, then the manual. This site compares what the listing titles state.