Review: BLF-348 (SingFire SF-348) Nichia Special Edition Flashlight (Runtimes, Output, Etc)

[mhanlen]

@KeepingItLight

Thanks for another good one! The time and effort you put into these is much appreciated. Here are the data I extracted from the vid.

BLF-348 – Measurements by MHanlen

Battery	Lumens	Candela	Distance	Runtime
Eneloop AAA	48	193	27	1 hour
Efest IMR10440	176	744	54	27 minutes

I could not tell for sure, but I think you were joking about the “thermal regulation” offered when running on Li-ion. I take the flickering to be a sign that the driver is overheated. Component values in the driver are evidently changing as they cyclically heat up and then cool down.

My own choice is not to use Li-ion. I think this light runs too hot on that battery.

I was being serious. I’m making an educated guess based upon a few things. First the brightening and dimming. I’ve done many video runtime tests now, and the only lights I’ve seen do this are ones with thermal regulation. The Noctigon Meteor and the Xtar H3 are examples- and if you watch my video reviews you can see this happen during the runtime test sections. Another piece of evidence: This thread here shows the BLF-348 light being disassembled with a 7135 chip used on the driver.

BLF 348 Output Mod

In my typical usage of this light I found that the standard output is sometimes a little brighter than I would like. I haven’t studied boost drivers much lately so I don’t how to mod them to adjust the output. I DO know what a 7135 is though. With that knowledge I started hunting for a lower output constant current driver. What I found is this . It comes in different outputs. I purchased 15mA, 20mA and 30mA samples. It’s a two-pin chip that is connected in series with the LED. It can go either b…

And this says that 7135 chips have built in thermal regulation.

AMC7135 - Thermal Fold-Back

I suspected but I wasn’t sure… the AMC7135 has a self-recovering thermal fold-back circuit that drops the output to about 250ma in a solid step. I was running 2x 7135’s on a brass strip opposite an XM-L. With the circuit was running at 700ma and with 4v input, it would fold back fairly quickly. A simple touch with a finger on the 7135’s would cool them enough to recover almost immediately. A 3.6V input lowered the occurrence. Nice thing to know.

I might be wrong though, so someone feel free to correct me as to why this isn’t true. Also, one other thing. The light does not have built in low voltage protection, so be careful about running the battery for the full runtime.