Guide comparing constant current and constant voltage LED drivers for lighting installations

How to Choose an LED Driver – Constant Voltage vs Constant Current Explained

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ALL LED · Electrical Trade Tips · LED · LED Drivers · Lighting Installation Advice
Posted by: electrical4less_mirek Avatarelectrical4less_mirek

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What to Consider When Buying an LED Driver

If you’re installing LED lighting, you’ll almost certainly need an LED driver. But how do you know which one to choose?

In this guide, we’ll help you understand how to choose an LED driver by explaining the differences between constant voltage and constant current drivers, which applications each one suits, and what to look for when making your purchase.

Whether you’re wiring a few metres of LED tape or powering an entire ceiling of panels, we’ll help you avoid costly mistakes and choose the right LED power supply first time.

What Is an LED Driver?

An LED driver is an electrical device that regulates the power to your LED light source. LEDs require a stable current or voltage to function correctly, and LED drivers ensure they don’t flicker, overheat, or fail prematurely.

There are two main types of LED drivers:

  • Constant Voltage LED Drivers
  • Constant Current LED Drivers

Which one you choose depends on the type of LED lighting you’re powering.

Constant Voltage vs Constant Current: What’s the Difference?

1. Constant Voltage LED Drivers

Constant voltage drivers supply a fixed voltage (usually 12V or 24V). They’re the go-to choice for powering:

  • LED strip lights
  • LED tape
  • Modules wired in parallel
  • Small decorative fittings

If your LEDs are labelled “12V” or “24V”, a constant voltage LED power supply is what you need.

2. Constant Current LED Drivers

These drivers deliver a fixed current (usually 350mA, 500mA, or 700mA) and adjust the voltage as needed. They’re used for:

  • LED panels
  • LED downlights
  • COB modules and integrated LED fittings

If your product requires a specific current (not voltage), use a constant current LED driver to prevent overheating or premature failure.

Do I Need a Dimmable LED Driver?

If you want your lights to be dimmable, you’ll need a compatible dimmable LED driver. Look out for the control method required:

  • TRIAC dimming (for trailing-edge wall dimmers)
  • 0–10V or 1–10V dimming (commercial lighting)
  • DALI dimming (advanced lighting control systems)

Always make sure the dimmer and driver are compatible — not all dimmable drivers work with all dimmer types.

What About Outdoor or Bathroom Installations?

If your LED installation is in a damp or wet environment, choose a waterproof LED driver with an IP65 or IP67 rating. These are sealed against moisture and ideal for:

  • Garden lighting
  • Outdoor signage
  • Bathroom zone installations

How to Size an LED Driver

The driver you choose must match the total wattage of your LED load. As a rule of thumb:

  • Add up the wattage of all LEDs in the circuit
  • Add 10–20% headroom for safety and longevity

For example:
If you’re powering 4 metres of 24V LED tape rated at 5W/m = 20W total → choose a 24V driver rated at 25–30W minimum.

Shop LED Drivers with Fast UK Delivery

At Electrical4Less, we stock a wide range of:

  • Constant voltage LED drivers (12V, 24V)
  • Constant current drivers (350mA, 500mA, 700mA)
  • Dimmable drivers for residential and commercial use
  • IP-rated waterproof drivers for outdoor and wet zones

Our range includes trusted brands like Aurora, ALL LED, and Knightsbridge, all available with Click & Collect from our Fulham trade counter or fast UK delivery.

👉 Browse our full range of LED Drivers

How do I know if I need constant current or constant voltage?

Check your LED product’s spec label. If it states a voltage like “12V” or “24V”, use a constant voltage driver. If it lists current like “350mA” or “700mA”, choose a constant current driver.

Can I use a higher-wattage driver than I need?

Yes — but don’t exceed the LED’s voltage or current requirements. Extra wattage capacity is fine and even preferred for longer lifespan

Are LED drivers universal?

No. Always match the output specs to your LED load. Using the wrong driver can damage your LEDs or cause failure.

What’s the best LED driver for 24V LED tape?


A 24V constant voltage driver with 10–20% more wattage than your total LED tape load. Choose an IP-rated one if installing in bathrooms or outdoors.

Conclusion

Choosing the right LED driver doesn’t have to be difficult — but getting it wrong can lead to flickering lights, failed installations, or even damaged LEDs. By understanding your LED product’s requirements and matching them to the right type of driver, you can guarantee a safe, long-lasting result.

Still unsure? Feel free to contact our friendly team at Electrical4Less or pop into our Fulham, London trade counter — we’re happy to help.

🔧 Recommended ALL LED Drivers – Full Range by Type

From compact 15W drivers to powerful 400W IP-rated options, ALL LED offers one of the most complete selections of constant voltage and current drivers available in the UK. Here’s our full recommended range — all available with Click & Collect or fast UK delivery.

🔌 12V Constant Voltage LED Drivers

🎛️ 12V TRIAC Dimmable Constant Voltage Drivers

⚡ 24V Constant Voltage LED Drivers

🌧️ 24V IP67 Waterproof LED Drivers (High Power)

⚙️ DALI/1-10V Constant Current LED Drivers

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