UI issue with the most common generic LED flashlight

LED Flashlights – General Info
1

howdy,

i just received a free gift from Liion Wholesale for ordering a couple of cells. (Vapcell G50)
they threw in a free flashlight i’m sure most of you will recognize.

i was going to give this to my folks for around the house, but when you turn it off, then on it goes to the next mode.
hi> med> low> strobe> SOS

anyone know how to get it to default to HI when turned on? i’ve tried waiting 10+seconds from off.

thanks

2

They’re almost universally garbage drivers.

What I did with a pair of AT01s was to just unsolder one LED wire so that it bypassed the controller/FET, and resolder it to where it just went through the parallelled chip-resistors, so it was 1-mode, high-only.

It was for mum, crappy 3×AAA light (she leaves lights on, so won’t trust her with a Li cell, protected or not), and it works fine. Still a crappy light, but at least now it doesn’t “flicker” and jump modes at random.

3

Oh yeh, look for the pads on the driver which go directly to battery-positive, and follow that trace / those traces to the paralleled resistors.

Solder the LED wire to the other end of those resistors.

4

thanks Lightbringer. how do i get access to the driver? the zoomie part doesn’t seem to unthread.

[edit]nevermind, i think i can get the bezel off.

5

There’s a reason these are free gifts… i wonder if these start draining money the more you have so obviously you would want to get rid of them

6

managed to get the bezel off (once i figured out one was fake xD) with a juice style can opener.
then used needle nose to act as a spanner wrench to spin the ‘pill’ out.

here’s the PCB.

lol

i feel inspired to make this more functional.

7

Yeah, pop off the bezel and lens, if you can’t unscrew the pill directly sometimes you can fully extend the tulip-part and “unscrew” while pulling hard.

Anyway, once the head’s off and the pill comes out, the driver’s probably almost certainly just press-fit into the pill, so pry it out with a needle.

Or if the LED’s star is just draped on top of a ledge of the pill, lift it up and poke out the driver with the eraser-end of a pencil.

8

thanks i got it. see above image please. i’m thinking just remove the 3 pin logic chip(?) and bridge the negative to the -LED pad?
[edit]

9

Looks odd. Are both the islands under the “ZZ-20-7” and connected to the blue wire, connected to the outer ground?

Normally, the LED hangs off the (+) rail directly, and the 7135s/resistors/FET/whatever, yank down on it to ground (linear, pwm, resistance, however).

I don’t want to guess wrong and have you short the cell and have it go pouf.

If the blue wire and “LI-LED-” is NOT grounded, then yeah, shorting as you did in green should work.

10

the entire ZZ-20-7 bit was ground. the positive wire was connected to the spring under the driver.
put my meter on the the -LED bit, and it was a little lower than the the 3V i put into it with my bench supply when on ‘High’.

so, i de-soldered the 3 pin chip and put a solder blob across. worked like a charm.
the light is 1 mode and pulling about 1.5A. powering it by a reclaimed Sony cell (SE US18650GR) which have low internal resistance and test about 95% capacity.

thanks for your help Lightbringer. :+1:

11

right on, good point. these are reclaimed cells. not worried about them being drained to low voltage.

thanks. :slight_smile:

12

Nope, it’s exactly that. Same annoying chip that was on my AT01s.

3-pins, acts like a 7135. +/- for power, 3rd is the output. It senses voltage drop, held up just long enough by the cap to switch modes, and uses a small FET to pass current to the LED.