AA Flashlight Wire Advice

Should I replace the 28 AWG that is currently in my Cheapo AA Flashlight Mod ?

The reason why I’m wondering is that when I have taken thermal measurements of the flashlight, there is a hot spot near the top of the tail spring. Seems like the wire/spring may be getting hot? I would expect that the high temperature would only be at the head.

I measure a whopping 1.8 amps with my DMM at the tail, so not much current.

I have a new reflector and AR lens coming from Kaidomain so when I take the flashlight apart again, just wondering if better wires would make a difference.

Thanks for any advice you may have.

It should help, one its larger so it can displace more heat, and two will decrease resistance. Even if the amps don’t go up. It will be more efficent especially as battery voltage drops

Maybe I shouldn’t post this in the middle of the night but wouldn’t this just make it worse? From what I’ve read the tail-spring doesn’t conduct as well hence the likely reason for the hotspot there. I’m guessing that a tail-spring bypass would be more helpful in getting rid of that hotspot.

In a few hours when I’m more awake this may sound really dumb lol.

Spring ‘bypass’ would help a lot.

The spring is already bypassed with the 28 AWG wire. I’m just wondering if a bigger wire would make a difference since it’s only an AA flashlight.

Oh.. When you say top of the tailspring, do you mean closer to the cell or closer to the switch? If switch, it's possible that the traces on the pcb are small and heating up so investigating that may help. 28 gauge wire is pretty small. I'd suggest you fit the biggest gauge wire possible for the most benifit.

Dang, I should have followed the link before I posted but maybe that points in another direction…Is the solder blob itself the point of greatest resistance now?

The wire size is not likely the issue. 28AWG copper wire resistance is 5.5 mR per inch.

i recently disassembled a tail switch such as the white one you replaced. It has all silver plated internals— the spring, spring cup and contact plate were all silver plated. The contact strips of the Omten switch look dull, like tin plating instead of silver. But i’m guessing there is a little solder tit at the top of the spring that is causing the hot spot, maybe it could be filed flat to increase contact area and reduce resistance?

I think you are right about this. I will put a solder blob on the entire top of the spring to spread out the contact area. Thanks much!

Here’s the solder blob on top of the spring.

And while I had the tail apart, I drilled another hole for the lanyard so the flashlight can tail stand better.

I retook temperature measurements and there is no longer a hot spot at the tail. Success!