LED STRIP POWER GUIDE
Enough power.
Safe wiring.
The strip, supply and cable all have to agree.
WATTS & AMPS
Start with the strip's worst-case load.
If a strip is specified in watts per metre, multiply that figure by the installed length. A 14.4 W/m strip at 5 metres is a 72 W load. Current is power divided by voltage, so 72 W at 12 V is about 6 A.
Addressable RGB and RGBW strips can have a much higher maximum load when every channel is at full brightness. Real animations may draw less, but the supply and wiring should be planned from a sensible maximum rather than the average effect you hope to run.
POWER SUPPLY
Leave headroom.
Avoid choosing a supply that has to operate at its printed maximum continuously. Around 20% headroom is a useful starting point for many maker projects. If the calculated load is 100 W, a supply around 120 W or more gives thermal and transient margin.
The voltage must match the strip. A 5 V strip needs a regulated 5 V supply; a 12 V or 24 V strip needs the corresponding voltage. More current capacity is fine because the load draws what it needs, but excessive voltage is not.
WIRE & INJECTION
Voltage drop gets worse with current and distance.
Long cable runs and high current cause voltage drop. Symptoms can include dimming, colour shift or unstable addressable LEDs at the far end. Thicker wire reduces resistance, and feeding power at more than one point can keep the voltage more consistent along a long strip.
Power injection does not mean joining different supply voltages. It means adding correctly fused feeds from the same suitable supply, with wire sized for the current. Fusing near the source helps protect wiring if a downstream short occurs.
For mains-powered supplies, enclosures, earthing and mains wiring need the same care as any other electrical equipment. If you are not confident working on the AC side, use a suitable enclosed or plug-in supply and keep the project on the low-voltage side.