Fenix TK61 - FET Driver Build

Well I had a TK61 with a Seis-Um driver from Richard which I built quite some time ago now. It was by far my longest throwing light and so when I showed it to a friend of mine he decided he just had to have one.

So I ordered the new light, contacted Richard about another Seis-Um driver and he said he only had one left and wasn’t sure if it would work properly or not. He gave it a good shot but it just wouldn’t play ball. So I thought about what to do and ended up selling my TK61 to my friend and have now set about modding this new one.

The first hurdle was the 2S2P battery carrier. That wasn’t going to work with the XP-L V6 0D de-domed emitter and a FET driver. So to start with I have converted the battery carrier to a 4P arrangement. The beauty of this is I’m hoping with some 30Qs or HG2s etc it shouldn’t suffer too badly from voltage sag.

I didn’t get a photo before I started with the carrier, but this is just after I started…

I then added some springs and joined all of the contact pads together so they are connected to the brass rods at each side. I used copper braid to make the connections to keep them flat so they wouldn’t foul on the carrier when I re-assembled it. Also added some copper braid to the springs.

At the top end, I had to cut some traces to break the connections and then joined the relevant pads together again. Plus some copper braid in the springs.

Someone with a very keen eye may notice a trace which needs cutting on the top side of the board. I did that after I had taken the photo.

The bottom end of the plastic carrier was recessed enough to clear the connections however at the top end I had to carve a V-shape into the plastic using my dremel. Its a bit hard to see in the photo but there is a V going from the centre out to the larger holes. I also had to open out the small holes a small amount for clearance to the springs.

Then all back together and it looks almost like a factory carrier again.

And just to make sure it’s working correctly.

That is where I am at for now. I have already ordered an XP-L V6 0D emitter which will get de-domed. I went with the XP-L as I keep hearing that the newer XM-L2s don’t handle high current well anymore and I didn’t want to change to an XP-G2 etc.

I am about to order an updated version 17mm FET driver from Richard with moppydrv firmware which I will piggyback off of the factory contact board.

Will update when some parts arrive.

Nice work. Are the batteries easy to install/remove from the carrier? I might have missed it but was there a reason for springs at both ends? Looking forward to how this turns out, I like the fenix big lights.

To be honest, it is a bit of a pain! But I didn’t like the factory arrangement as its just the spring pushing against the dome/board with no proper connection. I will use some brass round bar and replace the small springs at some point. But for now these will work.

Nice mod so far. Is the standard reflector staying and will you keep this torch?

Yep, keeping the stock reflector and I will be definitely keeping this one. I have learnt some things from doing my original one so I’m hoping to make this one perfect.

I have just stripped down the rest of the light and have hit another hurdle. A 32mm star is no where near big enough. The wires are going to foul on the reflector. Anyone know of a 44mm star that suits an XP base?

The reflector is plastic I believe? Can it be ground down and a spacer washer made up for the MCPCB?