A guide to LED power supplies (LED Drivers)
An LED power supply (also called an LED driver or LED transformer) converts your mains AC electricity into the DC power that LEDs need to operate.
Think of it like this: Your home runs on AC power, but LEDs need DC power. The power supply is the translator between them. Choose the wrong one, and your lights won't work - or worse, they'll be damaged.
📋 WHAT'S IN THIS GUIDE:
⚡ Choosing the Right Voltage (5V vs 12V vs 24V)
⚠️ CRITICAL: Your LEDs will be marked with their voltage (5V, 12V or 24V). Your power supply MUST match this exactly. A 24V supply will instantly destroy 12V LEDs!
When to use each voltage:
🔵 5V Power Supplies
Best for: Small, USB-powered projects
- TV backlighting (up to 2m)
- Display cabinet accents
- PC case lighting
- Battery-powered projects
Real Example: 2m LED strip behind a TV = 5V 30W power supply needed
🔵 12V Power Supplies (MOST COMMON)
Best for: Most home installations up to 5m
- Kitchen cabinet lighting
- Bedroom & living room strips
- Bathroom mirrors (with IP rating)
- Garden lighting (with weatherproofing)
Real Example: 5m kitchen cabinet strip = 12V LED driver at 60-100W needed
🔵 24V Power Supplies
Best for: Long runs over 5m & commercial projects
- Shop displays & retail lighting
- Office installations
- Architectural features
- Any run over 10m
Real Example: 10m retail display = 24V LED power supply at 150W+ needed
🔢 Calculating How Much Power You Need
Simple 4-Step Formula:
- Find your LED's watts per metre (it's on the product page)
- Multiply by your total length (in metres)
- Add 20% safety margin (multiply by 1.2)
- Round up to the next available size
📐 Real Calculation Example:
Your LED strip: 14.4W per metre
Your length: 5 metres
5m × 14.4W = 72W
72W × 1.2 (safety margin) = 86.4W
→ Choose a 100W power supply
❌ COMMON MISTAKE: Don't run a 60W supply for 60W of LEDs! It'll overheat and fail within months. Always add that 20% buffer.
🎛️ Making Your LEDs Dimmable
Not all dimmable power supplies work the same way. Choose based on what you already have (or plan to install):
TRIAC Dimmable
Works with: Standard wall dimmers
Best for: Home installations
- ✅ Uses existing dimmer switches
- ✅ Simple to install
- ✅ Affordable option
- ❌ Single zone only
DALI Dimmable
Works with: Digital control systems
Best for: Commercial buildings
- ✅ Control 64 zones individually
- ✅ Create lighting scenes
- ✅ 0.1% to 100% dimming
- ❌ Requires DALI controller
0-10V Dimmable
Works with: Low voltage controllers
Best for: Simple commercial
- ✅ Reliable & simple
- ✅ Works with sensors
- ✅ Good for retrofits
- ❌ Requires control wiring
💡 PRO TIP: Many of our power supplies accept ALL THREE dimming types (TRIAC, DALI, and 0-10V). Perfect if you're not sure what you'll use yet!
🔌 Plug-in vs Hardwired Power Supplies
Plug-in Power Supplies
Perfect when:
- ✅ No electrician needed
- ✅ Adding to furniture
- ✅ Temporary installation
- ✅ Under 100W total
Includes:
- 1.8m cable
- 2.1mm DC plug
- Safety protections
Hardwired Power Supplies
Best when:
- ✅ Permanent installation
- ✅ Over 100W needed
- ✅ Multiple LED runs
- ✅ Hidden installation
Options:
- IP20 (indoor)
- IP65 (bathroom/outdoor)
- IP67 (fully weatherproof)
⚡ Quick Power Supply Selector
Answer these 4 questions to find your perfect power supply:
30-Second Selector Tool
1️⃣ What's your LED voltage?
→ Check your LED product (5V / 12V / 24V)
2️⃣ How many watts do you need?
→ Length (m) × watts/m × 1.2 = _____W
3️⃣ Where's it being installed?
→ Indoor dry = IP20 | Bathroom = IP44 | Outdoor = IP65+
4️⃣ Need dimming?
→ No / Wall dimmer (TRIAC) / Smart system (DALI)
Common Setups - Quick Reference
| Project | Typical PSU Needed | Shop Link |
|---|---|---|
| 3m Kitchen Cabinets | 12V 60W Plug-in | View Options → |
| 5m Living Room | 12V 100W TRIAC Dimmable | View Options → |
| 10m Garden Path | 24V 150W IP67 | View Options → |
| Bathroom Mirror | 12V 30W IP44 | View Options → |
| Shop Display | 24V 200W DALI | View Options → |
❌ 5 Expensive Mistakes to Avoid
1. Wrong Voltage = Instant Death
24V power into 12V LEDs = immediate failure. No warranty covers this!
✅ Solution: Always triple-check voltage before connecting.
2. No Safety Margin = Early Failure
Running at 100% capacity overheats the PSU. Lifespan drops from 5 years to 6 months.
✅ Solution: Always add 20% headroom to your calculations.
3. Wrong IP Rating = Water Damage
Indoor PSU in bathroom = moisture failure within weeks.
✅ Solution: IP44+ for bathrooms, IP65+ for outdoors.
4. Incompatible Dimmer = Flickering
TRIAC dimmer with non-TRIAC PSU = flickering, buzzing, or no dimming.
✅ Solution: Match dimmer type to PSU type.
5. Voltage Drop on Long Runs
12V over 10m = dim LEDs at the end.
✅ Solution: Use 24V for runs over 5m, or add power injection points.
🔧 Professional Installation Tips
Installation Best Practices
📍 Location & Ventilation:
- Keep 10cm clearance around PSU for cooling
- Mount where accessible for maintenance
- Never bury in insulation
- Check ambient temperature rating
⚡ Wiring Safety:
- Use 1.5mm² cable minimum for long runs
- Keep AC and DC cables separated
- Add inline fuses for protection
- Label everything for future reference
📋 Planning Ahead:
- Zone circuits for easier control
- Include 30% spare capacity for additions
- Document your installation
- Keep spare fuses/connectors
✅ Ready to Choose Your Power Supply?
Browse Our Complete Range
Professional-grade LED power supplies with up to 7-year warranties
🤔 Still Not Sure?
Our technical team provides FREE consultation for any project
Email us: sales@weloveleds.co.uk
Include your project details and we'll recommend the perfect power supply within 24 hours
📚 Related Guides
- Deep dive: 5V vs 12V vs 24V power supplies
- Complete guide to TRIAC and DALI dimming
- Plug-in power supplies explained
- RGB controllers and color-changing LEDs
- Complete LED strip installation guide
Need help with your LED project?
Our experts can help with product selection and technical support.
Get Technical Support Browse Products