Total leds multiply by lumen of each led, then to multiply by 0.8 which is the lighting effect for the milky white cover, and to multiply by 0.9 which is lighting effect for transparent cover. For example,T81.2 milky white cover,276pcs leds. Each leds is 6-7Lumen:276*6.5*0.8=1435.2.
Remarks: luminous flux=qty of leds*Luminous*transmittance. The qty of the led is consult, and the luminous is affected by drive current, CRI and color temperature. The small driver current,. The luminous is small. High CIR, then small luminous. The high color Temperature, then big luminous. Light transmittance is also changing. There are several kinds of material for the cover, like PC, PMMA, plastic, etc. The light transmittance of the plastic can reach to 97%,and the light transmittance for the PMMA can reach to 93%, the light transmittance for the PC can reach to 90%,which means the light transmittance through transparent or translucent body with its the percentage of the incident light flux. Milky white cover with lower light transmittance. That is to say light transmittance=the material of the light transmittance*(1-dimness).