Highlights ► High irradiance close to 1000 Wm−2 of four single-color LED solar simulator and one red-green-blue simulator are constructed. ► High irradiance is achieved by pulsing LEDs with high input voltages, yielding more intense light outputs. ► Irradiance uniformity and temporal instability quality the five simulators as Class B. ► IV curves of a 12.5*12.5 cm2 X–Si solar cell, electrical parameters and resistances using these simulators are made. ► Low cost LED simulators operated under pulse operations giving fairly accurate results have been demonstrated.