LED Controller Power Sizing & Voltage Drop Calculator

LED Controller Power Sizing & Voltage Drop Calculator | Guangqi

LED Controller Power Sizing & Voltage Drop Calculator

Calculate the power supply current rating and the voltage drop along your DC run. Avoid the most common controller-side service call: undersized power and unmanaged voltage drop on long fixture chains.

System Inputs

Drive voltage

Load per metre (W/m) or per fixture (W)

Run length / fixture quantity (m or units)

Cable cross-section (mm²)

Single-leg cable length (m)

Power headroom (%)

Sizing Result

144 W

Total load

6.0 A

Current draw

7.2 A

PSU rating (w/ headroom)

0.83 V

Voltage drop (round-trip)

Voltage drop < 5% — within safe range for 24V LED runs.

Calculation: I = P / V, voltage drop V_drop = (I × 2 × L × ρ) / A where ρ ≈ 0.0175 Ω·mm²/m for copper. Round-trip cable factor (×2) accounts for + and – legs. Acceptable voltage drop on 24V DC is typically <5% (≤1.2 V) at the far end. For 12V runs the same percentage means a tighter absolute budget — keep cables short or upsize gauge.

Need Hardware Assistance?

Need help matching a Guangqi controller and PSU pair to this configuration? Our engineers can recommend specific SKUs and supply a wiring diagram with the quote.

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