Can anyone tell me if changing either of the two resistors would increase output any on this old fenix driver I have sitting around? Output is about 800mAh to the emitter, even 1A would be better, 1.5A would be perfect but that seems like a lot.
Resistors (Values I believe are .25 and 1ohm but not sure)
Looks like that open spot at the bottom is in parallel with the others. Maybe you could add another resistor there. Another .27 might be pushing it hard…. what resistors do you have in the parts drawer to try?
I think those are the resistors associated with the buck boost circuit…changing those will throw off the equilibrium of the IC and make things go squiffy
Those drivers aren’t like linear regulators…and without some sort of schematic or even knowing what the circuit is doing it’s hard to tell what changing those values would do
What is this IC (he small 6 pin one between the inductor and diodes
CFA7E? hard to tell
Might wanna go over that board with some 91% rubbing alcohol too
Googling “FA7F buck boost ic”…came across this http://www.ti.com/lit/ds/symlink/reg71050.pdf
my bet is that IC is a boost converter.
I assume this driver is one mode. I think you may be SOL on bumping up output with just a resistor. It looks like you will have to redesign the whole circuit to crank up the amps.
Fenix tends to make quality efficient drivers, so it’s worth putting it to some use, even as is. Every boost driver I used (very few at that) uses a sense resistor to regulate current, and that R27 and 1ohm in parallel (makes for .2126 ohm)sure looks to be made for the part. (The controller measures and regulates voltage across the resistor, by adjusting/regulating current out.)
Typically… Current out = Constant / R.
So if you are getting .8A from .2126 R, .17 is your Constant for that driver…
.8 = .17/.2126 ….
So R = .14 should get you about 1.2 Amp out.
(this method works for BB Nexgen and Mini-01 boost drivers I have modified)
Use one of the many parallel resistor calculators online to calculate various combinations of resistors to get what you want…
Cool nice!
Will that small boost circuit be able to handle 1.2A? If he was to jumper across that resistor would it run wide open [and would components be able to run like that without burning out]?
Good questions, but I’m not good for those answers; I’m the Low Lumen, my mods tend to go in the other direction. To run reliable, longer and not self-destruct if left on indefinitely.There are current limits to some components like the driver and diode, and pushing a boost driver harder they eventually get very inefficient, coil saturates, etc. I think likely you are safe to run in the 1-1.2A range, but really should find the spec on the driver. The diode looks big enough to handle it.