Current draw of Dewalt DCL050 20V Max LED Hand Held Area Light

I recently purchased a Dewalt DCL050 light and while reading reviews there seemed to be a lot of questions about current draw / battery life. Dewalt claim a maximum of 22 hours but that’s about all I could find in official documentation so I thought I’d attach it to a lab power supply and measure what it actually draws. I had the PSU set to 18V which is the nominal voltage and results were as follows:

Low setting (250 lumens) = 240 mA
High setting (500 lumens) = 460 mA

With the low setting the instantaneous current draw skips around because of the PWM used to dim the LEDs so the above is a 10 second average. The largest Dewalt battery is 5 Ah and 5 / .24 = 20.8 so the 22 hour maximum sounds plausible given that batteries are normally rated for a 10 hour discharge and often perform a little better at lower discharge rates. Here’s a little table of roughly what it would be for the common battery capacities that I know of:

Capacity (Ah)   Low setting    High setting
1.3                 5 hrs           3 hrs  
  2                 8 hrs           4 hrs
  3                13 hrs           7 hrs
  4                17 hrs           9 hrs
  5                21 hrs          11 hrs
  6                25 hrs          13 hrs