Binning at 85°C makes the initial part of the design process slightly easier and more intuitive. For example, if a
designer were working on an LED system that required 1000 lumens at temperature (85°C), then 10 LED lamps
with a luminous flux of 100 lumen per LED binned at 85°C could be selected. This would make it easy to estimate
the performance of these LED lamps in this real-world situation (10 LEDs * 100 lm = 1000 lumens). On the other
hand, if the LEDs were binned at 25°C, the same 10 LED lamps would need to be binned at 114 lumens each and
de-rated per the mathematical framework in Figure 3 to arrive at the same 1000 lumen goal at the system level.
So, the good news is binning at 85°C makes the first-pass math more intuitive. The bad news is you still have to do
the same math if your system runs – or ever runs – at any temperature other than 85°C. Examples of this would be
outdoor luminaires (60-65°C is much more common) or freezer cases (20-25°C is typical) or downlights in Insulated
Ceilings or almost any retrofit bulb (often over 100°C). In each of these cases the value of binning at 85°C is lost
and the designer is back to doing the same math from a new mathematical framework where, arbitrarily, 85°C is
now set to equal 100%.