Howdy, long time lurker, first time poster.
I’m not much of a flashaholic at this point, but I’m getting worse. I have a bunch of lights and I use them for wrenching on lawnmowers, automobiles, etc…
This is a short review of the Braun 390 Lumen Magnetic Slim Bar Folding LED Worklight from Harbor Freight. I picked up two of these for $24.99 with coupons in Rochester, NY. I live in Toronto, so it was a bit of a jaunt to get these.
These flashlights are similar to the Astro Pneumatic Tool 40SL 410 Lumen Rechargeable COB LED Slim Light but for about 1/3 of the price. The strong magnetic base is really appealing to me since a lots of automobiles are magnetic these days 
The light takes a single removable 18650. It came with a 2200mAh rated battery. I put it through a few discharge/recharge cycles and measured the capacity to about 2050mAh, so including losses to heat, shoddy wiring, etc., I have no doubt that the capacity is well within the advertised ballpark. The flashlight has a micro USB port for charging the battery and comes with a USB cable.
The Braun 390 can flip the COB through 180 degrees. It has 2 modes to drive the COB: low and high. The low mode is achieved using a 247Hz PWM frequency. I can notice the flicker while the light moves, but if it’s stuck on a car then it’s not too big of a deal. I usually roll at full brightness and having two of the lights at my disposal makes tag teaming a reality. There is a third mode that lets you flip to flashlight mode. I find this mode unnecessary so I didn’t measure anything coming out of the single LED at the tip of the swivel head.
The following picture is an o-scope trace of a BWP34S photodiode measuring the PWM frequency of the Braun 390’s COB.
The quiescent current of the flashlight in its off state is 0.35 to 0.49uA. In low mode the current is 245mA. In high mode the current is 842mA. On a 2200mAh battery, this should give a run time of 8.97 and 2.61 hours, respectively. In practice, I only run in high mode and this does feel close to accurate. I don’t get anxious about current consumption with this light.
The low quiescent current means that I have no problem leaving the battery in the light for weeks or months without use. I haven’t disassembled the flashlight yet, but I’m guessing this absurdly low quiescent current is due to a physical off switch as opposed to an electronic latch/transistor.
A few nitpicks: the threads are unlubricated. The ground spring has a seal or o-ring installed incorrectly on both of my lights.
Conclusion: great work light, strong magnetic base. It’s great for my uses. Wouldn’t run with it in low mode due to PWM, but whatever…
Sorry for the lack of pretty pictures, but this is my first rodeo!
