Fandyfire C3 - doesn't work with 1xAA, but ok with 2, plus questions...

Hi,

I just received one of these Fandyfire C3 lights:

https://www.fasttech.com/products/0/10007963/1700407-fandyfire-c3-1-cree-xr-e-q5-1-mode-150lm-neutral

I tried it with 2 x AA (Eneloops), and it works fine, but when I try it without the extender with 1 x AA, it won’t light up.

I saw that FT sells the C3 for 1xAA, without the battery extension tube:

https://www.fasttech.com/products/0/10001763/1128003-fandyfire-c3-cree-xr-e-q5-160lm-1-mode-white-led-f

so I don’t understand why the one I have won’t work with 1xAA?

One thing I noted is the tailcap spring is loose, almost like it’s not attached to anything, but just sitting in the tailcap behind the white nylon ring. Is that normal?

Finally, does anyone know if this light should work with 1 x 14500 and also what about 2 x 14500?

Thanks, and sorry for all the questions,
Jim

I think 1.5v is its minimum working voltage, so one AA Eneloop just isn’t enough.

I don’t know anything about the light. I assume a 14500 would be fine, but two would probably kill it, seeing as it has a boost circuit, and not a buck.

can’t help with the AAs though.

Try to make short between the edge of the tube and the negative end of battery.

Threads look anodized, perhaps the main tube doesn’t make a good ground with the tail cap.

bushwhacked,

I’ve been messing with it more, and I think that what you were thinking was close.

As you said, the threads on both the smaller (the 1xAA one) tube and on the extender are anodized, with only the ends unanodized.

It looks like the “intention” was that the edge of whichever tube the tailcap is screwed into is suppose to contact the edge of a metal “cup” inside the tailcap. The spring I mentioned is not actually attached to anything, but rather sits on top of a small metal washer, and then there’s a plastic/nylon ring that screws into that metal cup and pushes the spring so that it’s in contact with the metal washer.

So, whichever tube is with the tailcap, the unanodized edge HAS to contact the edge of the cup that’s inside the tailcap. But the problem is that the space between plastic ring and the edge of the tailcap is, I think, too narrow, so when I try in the 1xAA configuration, the edge of the tube can’t squeeze into that space between the plastic ring and the edge of the tailcap, so it can’t contact the edge of the metal cup.

Once I figured that out, I was able to finally get the 1xAA working, but with some effort. What I did is to remove the head, then screw the 1 tube into the tailcap really hard. Then, I put the battery in, and screwed the head back on, and it started working.

I think that when the head is attached, it’s too hard to screw the tailcap in far enough.

Jim

Boy ohaya, you sure have been having a lot of trouble with extenders lately.