Channel letter PSU sizing, what wattage buffer to add?
Posted: Sun Jun 28, 2026 8:00 am
Sign shop question. Customer wants 4ft channel letters, 60 white LED modules.
Each module datasheet: 0.72W @ 12V. Total: 60 x 0.72 = 43.2W.
Do I size PSU at:
Sign industry veterans: actual derating rule of thumb? I usually go +30% but had two PSU failures in 18 months recently. Reconsidering.
Each module datasheet: 0.72W @ 12V. Total: 60 x 0.72 = 43.2W.
Do I size PSU at:
- Exact: 50W meanwell, run hot
- +30% buffer: 60W, conservative
- +50% buffer: 75W, expensive but lasts
Sign industry veterans: actual derating rule of thumb? I usually go +30% but had two PSU failures in 18 months recently. Reconsidering.