Resistor mod possible?

Flashlight Modding and DIY Parts
1

Hey!

This is the driver on my new Convoy C8+ with SST-40 led and its pulling 3.5A at tail on high and 1A at medium/low. It seems to get quite hot quite fast on high put id still like to push it more because the SST-40 should be really cabable led. Ive attached few pictures of the driver and is there any current sensing resistor or something, so i could parallel another resistor to add more current? There is atmel attiny 13 clearly but i cant figure what the 6788 GA2K2V is.

Greeting's from Finland!

2

It appears to be a FET. The sense resistor is the one marked R005.
I doubt going any lower with the resistor is going to help much. Changing the FET may help changing to one with better specs. I dont know what the specs of this one is. You may be able to just bypass the resistor all together but it appears to be just a direct drive driver with a very small resistance added to limit current somewhat. Just my guess as Im not a EE just a modder.
Another thing that effects current is the battery thats used. I would recommend a 30Q if your not already using a low IR cell.

3

Im using GOOD Efest 2800mah’s and lot of samsung’s 18650-13Q, they should be still cabable of 15A. Im waiting on post to arrive my LG HE2.

4

3.5A seemed low on the sst-40 with this new driver.

I have similar suspicions with moderator007 about battery being a limit here but I guess SST-40 on my set isn’t going any higher than 4 amps too.
I am able to get close to 8 amps on this driver only on nichia 219c triples with spring bypass and single use LG HE4 (this battery died fast when I used it on this combo)

But according to Simon’s aliexpress his driver will float around 4.5A to 6A so maybe update us when you get your HE2?

5

What driver is it, is it the 6A driver?
It might have temperature stepdown, which lowers the output so the light will not exceed about 55 DegC.

You can disassemble the NTC to get rid of the stepdown.

6

The Fet used in this driver is a good brand name Fet its an alpha and omega Fet. Capable of very high amperage output.

https://alltransistors.com/mosfet/transistor.php?transistor=22148

Are you using the stock multimeter leads? These leads have high resistance which makes the amperage reading lower.

7

How are you measuring the amp draw? I suspect it to be much higher in reality.

8

There's no need to do tailcap readings with such driver, it's regulated. As it comes stock it allows up to 8A of current (a tiny bit less in practice), of course depending on input/output deltas (effective driver input after substracting all losses and emitter Vf at the resulting output current).

Using a standard multimeter poking at the tailcap and expecting any sort of accurate current readings is nonsense. In doing so you are inserting a big roadblock to the current path.

9

only proper way is measuring with clamp meter

as far as I remember the driver should deliver 5 or 6A

remember that FET burns off all voltage overhead so it gets pretty hot in medium mode
the modes might be chosen to avoid the maximum heat current value, so changing resistor might get that worse while increasing max output basically to DD