How to Calculate the Number of Power Supplies Required for an LED Display

When designing an LED display project, one of the most common questions is: “How many power supplies do I need?”
If you configure too few, voltage drops and dead pixels will occur under full brightness. If you configure too many, both cost and maintenance complexity increase.

This article provides a practical calculation method and, at the end, recommends specific power supply models suitable for LED display applications.

Step 1: Clarify 4 Key Inputs

1. Operating Voltage – LED display modules and receiving cards typically use 5V DC (some accessories or fans may use 12V/24V).
   
   

2. Load Power Basis – Decide whether to use maximum power (Max) or average power (Avg). For sizing, always calculate based on maximum power to ensure stability under full white, aging tests, or extreme temperatures.
   
   

3. Derating & Redundancy Strategy – In engineering practice, power supplies are usually loaded to 70%–80% of their rated power for reliability and heat margin.
   
   

4. Wiring Method – How many modules per cabinet? How many cabinets per PSU? Longer cables increase voltage drop, requiring more margin or distributed power supply.
   
   

Step 2: Core Formula

Let:

• PtotalP_\text{total}Ptotal: Display maximum total power (W)
  
  

• PpsuP_\text{psu}Ppsu: Rated power of a single PSU (W)
  
  

• α\alphaα: Utilization factor (typically 0.7–0.8, use 0.8 in this example)
  
  

The required number of power supplies is:

N  =  ⌈PtotalPpsu×α⌉N \;=\; \left\lceil \frac{P_\text{total}}{P_\text{psu}\times \alpha} \right\rceilN=⌈Ppsu×αPtotal⌉

For N+1 redundancy (recommended for stage or outdoor continuous operation), add 1 extra PSU as backup.

How to determine PtotalP_\text{total}Ptotal:

• If the manufacturer provides maximum power per m²:
  Ptotal=Area×Power DensityP_\text{total} = \text{Area} \times \text{Power Density}Ptotal=Area×Power Density
  
  

• If per cabinet/module max power is given: multiply and sum up.
  
  

• Rough estimates: indoor screens typically 450–650 W/m², outdoor 650–1000 W/m².
  
  

Step 3: Typical Calculation Examples

Example 1: By Area & Power Density

• Screen size: 3 m × 2 m = 6 m²
  
  

• Max power density: 600 W/m²
  
  

• Ptotal=6×600=3600P_\text{total} = 6 \times 600 = 3600Ptotal=6×600=3600 W
  
  

• Using 5V / 300W PSU, with 80% load → effective power per unit = 240W
  
  

• ⇒N=⌈3600/240⌉=15\Rightarrow N = \lceil 3600 / 240 \rceil = 15⇒N=⌈3600/240⌉=15 PSUs
  
  

• With N+1 redundancy: total 16 PSUs
  
  

Example 2: By Cabinet/Module

• Each cabinet max power: 200 W
  
  

• Total: 12 cabinets → 200 × 12 = 2400 W
  
  

• Using 5V / 200W PSU, effective per unit = 160W
  
  

• ⇒N=⌈2400/160⌉=15\Rightarrow N = \lceil 2400 / 160 \rceil = 15⇒N=⌈2400/160⌉=15 PSUs
  
  

• If one PSU per cabinet: minimum 12, but 15 or N+1 redundancy is safer
  
  

Step 4: Engineering Considerations

• Voltage Drop – 5V is low voltage but high current; long cables cause significant drop. Use thicker wires, multiple supply points, or shorter runs.
  
  

• Cooling – Below 200W many PSUs are fanless (natural convection). At 300W, most have fans. For noise-sensitive or slim cabinets, choose ultra-thin fanless designs.
  
  

• Input Side – Confirm AC input range (commonly 90–264VAC), surge immunity (e.g., 300VAC for 5s), and site conditions (altitude, low temperature).
  
  

• Certification & Reliability – For stage or commercial projects, prioritize PSUs with UL/CE certifications, vibration resistance, and at least 3-year warranty.
  
  

Step 5: Quick Selection Guide

• Small screens / ≤2 m² → 5V / 90–150W PSUs, short cables.
  
  

• Medium screens / 2–10 m² → 5V / 200W PSUs, distributed per cabinet.
  
  

• Large outdoor/high-brightness screens → 5V / 300W PSUs, thin and fanless if needed.
  
  

Step 6: Wiring & Protection Checklist

• Use main trunk + branch distribution, with fuses or breakers per branch.
  
  

• Ensure tight crimping of terminals to avoid heating.
  
  

• Power the control system/receiving cards separately to reduce interference.
  
  

• Implement grounding and equipotential bonding for safety.
  
  

• Reserve maintenance space and cable ducts for easy replacement.
  
  

Step 7: Recommended Power Supply Models (for LED Display 5V Applications)

✅ With this method, you can confidently calculate the required PSU quantity, avoid underpowering or overspending, and directly choose reliable models like UHP-200A-5 or UHP-350-5 for your LED display projects.