I was just wondering about the input voltage as there are 4 cells contacting the + terminal simultaneously, so I assume a 4 cell lipo would provide the same voltage.
I'll have a go with a meter and see what I can see.
May I ask which point is the FET gate? Is it to the left or right of q1, or the top of the FET as pictured above? (or indeed somewhere else...).
lalalandrus: Unfortunately I don't have any other resistors, nor I feel, the ability to replace the existing ones. I should leave that to those with more experience and skill than I have.
From the looks of things it looks like those 4 resistors are connected in series and not in parallel. Shorting across one won’t do much to change the current. Try shorting out two, then three, then all four and see what happens. YMSMBR (your magic smoke might be released) but unlikely.
No, on my monitor it looks like those darker areas are etches covered by solder mask (they look raised and smooth). The dimmer areas look like slightly textured bare PCB covered by solder mask.
If that is an etch running under the resistors… it couldn’t be a continuous etch, but maybe the etch goes in under the center of the resistor and jogs left to the left resistor pad. The etch that goes out connects to the right resistor pad and jogs left and back out the center of the resistor. Definitely not how I would lay it out…
texas, comfy is referring to the fact that your comment on the resistors is wrong, in a parallel configuration shorting one resistor is sufficient, it is series where your logic will hold.
led torch, to pull the gate wide open, tie r5 (anyside) to K+ (red wire), but this will still be limited by the 4 13ohm resistors in parallel (3.2 ohms) which isnt very bright, you need to find a < 1 ohm to pull ~5A or just less than 3w per led.
one way to do this is with a long length of thin wire that you can use a ohm meter to test the resistance with, this is only suitable for testing however as it will generate lots of heat. also you should monitor the LED heat as you test this as well. you only need in theory .25 ohms
In my post I said the resistors look like (on my monitor) they are in series and not in parallel. If they are in series, shorting one resistor won’t do much to change the current. If they are in parallel, shorting one resistor shorts them all.
Just make sure you don’t do it for too long (<5s) and monitor the temps. At .03 ohms plus other minor losses it is close to the limit of the leds. To be on safe side use not fresh batteries.
Yes, but it doesn't need to be soldered. Actually best if it's not. You need to switch it on, watch the ammeter, then touch the jumper wire to the FET, and see if/how much the current changes. I would just use tweezers, from the hole in the center over to the FET. They're right next to each other.
'K+' is nothing to do with this, that's just the pad that gets grounded when the switch is pressed. Dunno where that suggestion came from.
Are you testing with the original LEDs, still in the head of the light?
Momentary switch is between GND (K-) & MCU pin 3 (K+). Grounding that pin instructs the MCU to do... whatever it's programmed to do - change modes, turn off, go to strobe if it was a double press, etc.
OP: Is there anything hidden under the big capacitor? (for the alternate configurations that use the optional inductor between B+ & LED+, the center hole and the LED+ pad would have to be separate somewhere under there, those two separate pads must be connected by something - is there another limiting resistor there?)
Comfychair - There is nothing under the capacitor other than gold pads. Photo below.
Before I read your reply, I went to put the torch to one side and in my ignorance screwed the thing together, it lit up without me touching the switch, but thankfully there was no difference in brightness from normal and so no damage was caused.
Hopefully this will mean something to you.
Oh, and yes, it still has the original LEDs as supplied, all constructed as normal. I just unscrew the body and gently lever the driver out to make changes.
You are aware that it takes a rather large amount of extra light before your eyes can pick up any apparent difference, right? That's why I suggested using a temporary jumper, so you can touch/remove/touch/remove/etc. while looking at it. You won't be able to spot it otherwise. Even a jump from 2000 lumens to 3000 is impossible to notice, unless you compare them in rapid succession (or two lights side by side at the same time).
So 1 & 2 are the same pad, and 3 is isolated, separate? I guess those unused pads at #3 are for when there's an inductor/diode present - one round pad for LED+, the other for one leg of the inductor.
Is there a through-hole at #3 where I have a red dot?
Anyway... I don't think you've tried it yet with the resistors properly bypassed, correct?
