Choosing the wrong LED driver is the most common reason a strip lighting install fails early — flicker, overheating or a dead driver within months. This guide gives you the simple rules we use at the trade counter every day.

What does an LED driver do?

LED strip runs on low-voltage DC (usually 12V or 24V), but your mains supply is 230V AC. The driver converts mains power to the steady low-voltage supply the strip needs. An undersized or mismatched driver is the number one cause of flickering and premature failure.

Step 1: Match the voltage

This one is non-negotiable: a 24V strip needs a 24V driver, a 12V strip needs a 12V driver. Connecting a strip to the wrong voltage will either kill it instantly (too high) or leave it dim and unreliable (too low). Check the printing on the strip itself if you’re unsure. Browse our 12V drivers and 24V drivers.

Step 2: Constant voltage vs constant current

LED strip almost always uses a constant-voltage driver — that’s what the 12V/24V rating means. Constant-current drivers (rated in mA) are for certain downlights, panels and single-chip fittings, not for standard strip. If you’re buying for strip, you want constant voltage; for other fittings, check the lamp’s specification. We stock constant-current drivers too.

Step 3: Work out the wattage — and add 20% headroom

The rule:

Strip wattage per metre × total metres × 1.2 = minimum driver wattage

Running a driver at 100% of its rating shortens its life and can cause flicker; the 20% margin keeps it cool and reliable.

Worked example

You’re fitting 5 metres of 24V COB strip rated at 12W per metre:

• 5m × 12W/m = 60W of strip
• 60W × 1.2 = 72W minimum
• Choose the next driver size up — a 75W or 100W 24V driver

Two separate runs? You can either use one larger driver feeding both (add the wattages together, then add 20%) or a separate driver per run — often tidier for kitchens where runs are far apart.

Step 4: Check the IP rating for the location

Indoors in a dry ceiling void, a standard IP20 driver is fine. In bathrooms, under worktops near sinks, or outdoors, use a driver with a suitable IP rating (IP65/IP67) or house the driver remotely in a dry location — often the neatest answer.

Step 5: Dimming

Standard drivers don’t dim. If the job calls for dimming, you need either a dimmable driver matched to the dimmer type (mains/TRIAC, 0-10V or DALI), or a separate receiver/controller between a standard driver and the strip — that’s how most smart and RGBW systems work. Check compatibility before you buy; mismatched dimming is the second most common callback after undersized drivers.

Quick checklist

• Voltage matches the strip (12V or 24V)
• Constant voltage for LED strip
• Wattage = strip total + 20% headroom
• IP rating suits the location
• Dimmable driver if dimming, matched to the dimmer type

Need it today?

We keep LED drivers, LED strip and aluminium profiles in stock at our trade counter at 398 Harrow Road, London W9 — same-day collection, or fast UK delivery. Not sure what the job needs? Bring the strip spec in and we’ll size the driver with you.

Trade accounts save up to 20% — register in two minutes. For installation work, always use a qualified electrician.

Walk into any wholesaler and you’ll hear the same question: COB or SMD? Here’s the practical difference, and which to pick for the job in front of you.

The short answer

COB gives you a continuous, dot-free line of light. SMD gives you individual points of light that usually need a diffuser to look smooth. If the strip will be visible — coving, shelving, plinths — COB nearly always looks better. If the strip is fully hidden or budget is the priority, SMD still earns its place.

What’s the actual difference?

SMD (surface-mounted device)

Discrete LED chips (you’ll see codes like 2835 or 5050 for the chip size) mounted along the strip at intervals. Each chip is a visible point of light. Seen directly, or reflected in a worktop, you get the familiar “dotting” effect — which is why SMD strip is usually installed in an aluminium profile with a milky diffuser.

COB (chip-on-board)

Many tiny chips mounted in a continuous line and covered with a phosphor coating. The result is one unbroken ribbon of light with no visible dots, even without a diffuser, and a wide, even beam. It looks premium straight off the reel.

When COB wins

• Visible runs: coving, open shelving, kitchen plinths, glass cabinets — anywhere you or a reflection can see the strip itself
• Tight curves and corners: the continuous chip layout tolerates bends gracefully
• Minimalist installs: dot-free light without needing a deep diffuser to hide spotting

When SMD wins

• Hidden runs: inside a profile with a diffuser or bounced off a ceiling, the dots disappear anyway — so pay less
• Colour-changing systems: most RGB, RGBW and addressable/pixel strip is SMD-based
• Budget projects: like-for-like, SMD is usually the cheaper metre

Do I still need an aluminium profile with COB?

For a professional job, yes — just for different reasons. With SMD the profile’s diffuser hides the dots. With COB the light is already smooth, but the aluminium channel still matters: it pulls heat away from the chips (extending LED life), protects the strip, and gives a clean, finished edge. See our aluminium and plaster-in profiles.

Whichever you choose, size the driver properly

Both types run on 12V or 24V DC and need a constant-voltage driver with around 20% headroom above the strip’s total wattage. Full walkthrough here: How to choose an LED driver.

See both in stock in London

We stock dot-free 24V COB strip, RGBW SMD tape, IP67 neon flex and all the connectors and accessories at our trade counter, 398 Harrow Road, London W9 — same-day collection or fast UK delivery.

Trade accounts save up to 20% — register in two minutes. For installation work, always use a qualified electrician.