I was expecting a difficult mod due to the tiny irregular space in the head for all the new electronics.
However, the mod went surprisingly smoothly and the light worked on the first try. The hardest parts were filing the star and optic down to fit in the cavity and then figuring out the best way to attach the positive and negative wires to the body under the star.
For the positive wire I ended up using the stock contact board. I strung a long piece of 24 gauge wire through the pass-through hole in the shelf, all the way through outside the bottom of the light. I then soldered it to the contact board and added a bit of thermal epoxy around the solder to help insulate it. Then I pulled it back up into position at the top of the battery compartment, cut it off and then soldered it to the board.
For the negative wire I inserted one of the original driver retaining screws, wrapped a short piece of 24 gauge wire to it and soldered it directly to one of the contacts on the bottom of the switch.
When I inserted the driver (15mm Mountain DD driver flashed with Anduril) I used a solder bridge to connect the edge of the driver to the switch with the negative wire. I used a 26 gauge wire to connect the pin on the Atiny to the other switch contact.
I took more pictures and plan to post a build thread later today.
On the K9.3 driver the sense resistor is 10mΩ and and the sense voltage is bumped to 90mV compared to 50mV in the 5A KR4/D4V2.5 driver (also with 10mΩ Rsense). I assume it’s the same for the 7.5A driver, no change to Rsense and Vsense = 75mV.
I am not sure, i will have to look at it, maybe someone can share a picture of what that should look like?
I know, i ordered these 6 weeks ago. Had i realized i was using a sft40 i would've asked for one of them to be 9amp. but then again, heat is a factor, so 7.5a might not be terrible in that small host.
hmm. this sounds interesting. would you be able to share with me what part would be needed, and where it should be soldered, to make this change? I have a feeling i get the concept of what needs to be done, because -
I feel like there is an old Matt Smith (Adventure Sport) youtube video where he mods a driver of some sort by soldering / stacking resistors onto each other to get more current? I wonder if this is the type of mod you and JaredM are referring to?