Any help with resistor mod of Convoy 6A driver?

Flashlight Modding and DIY Parts
1

I was playing with it recently but failed to improve it.
When I stacked another R010 on the top - the driver didn’t work.
When I stacked R475 - the output dropped from 5,80A to 5,46A

Any ideas?

I need it to be 7-8A.

2

Stein

you might wanna take a look in THIS thread.
Barkuti gave some useful info there, and i did experiment with the given advice and achieved good results.

“If the driver uses R010 for 6A this means sense voltage is Vsense = R × I = 10mΩ × 6A = 60mV. If you want to add 1.5A, you need Rextra = V / I = 60mV / 1.5A = 40mΩ or an R040 in parallel with the existing R010.”

3

Another 10mΩ should have given you 12A (or a bit less if real current was 5.8A, + stacking might add some tiny amount of resistance), if it didn’t work I can’t think of another reason than a problem with the soldering.

If you want 7.5A : R = (6 x 10) / 7.5 = 8mΩ
Or 7.5mΩ for 8A.

4

And connect black wire straight to any mosfet output.

5

Try stacking a single R030 on top of the existing R010. That worked for me.

6

Thanks guys. I will follow your hints.

:beer: :beer: :beer: :beer:

7

I’ve just stacked R020 on the existing R010. The driver works but now it gives 5.41A.

What am I doing wrong?

Does the led or resistor size can be the reason? The stacked R020 is smaller (maybe half the size of R010) and I test it with SST-40…

8

Change battery

9

Is there a schematic of the board?

Might there be a comparator or other type of circuit which is used to limit the max allowed current in addition to the current sensing?

Does the max current correspond to 100% pulse width of the PWM to the FETs?

10

The battery i use for testing is 21700 Samsung 40T which is capable of delivering high power. I don’t think it can limit the driver’s output.
@kenny - I’m no electrician, hard to answer your question. My little knowledge comes entirely from blf. Nonetheless I’ve moded many Convoys L6 adding resistor and never had such problems.

11

What current do you measure without additional resistor? (Just with the original R010)

12

5.80A

13

The sense resistor needs to dissipate some power, so smaller is not ideal.
However, it’s strange that the output decreases.

14

I wondering wtf track is for. Use fat wires and connect straight to fets output and measure.