I currently keep an older Ultrafire HD 2011 18650 light in the visor organizer of my vehicle. Is there a similar tube style light that also has a mechanical lockout that can eliminate parasitic drain? I can go for many months without using this light.
Couldn't you just partially unscrew your Ultrafire HD 2011 to eliminate parasitic drain?
I tried and it stayed on pretty much until the tail cap came off.
I tested my BLF A6, and unscrewing it just a little bit works fine.
I don't know if you like the A6, but it's practically the same thing as the Astrolux S1.
It’s the threads.
If they’re not anodised then the entire thread will be conducting til it falls off.
The ones that unscrewing works on have anodised threads and only conduct through the end of the tube so backing off the cap disconnects it.
An 18650 tube light with a XML led is fairly common.
A very quick look shows this convoy with that spec with anodised threads so unscrewing should work: https://www.aliexpress.com/item/826041434.html
Not quite sure why the OP needs a mechanical lockout.
Only lights with electronic switches or magnetic rings have parasitic drain. Lights with clicky switches don’t have any parasitic drain when the switch is off. Most inexpensive tube lights use clicky switches.
That’s because with a clicky switch, all the power flows directly through the switch. Click the switch to the off position and you disconnect the circuit completely. No electricity flows and there is no parasitic drain.
I was worried I could have drain because a different tail clicky had the negative end of the AA cell corrode against the tail cap spring and I assumed this was due to a small drain over time?
Alkaline AA cells may leak and corrode over time even when not installed in anything. This is why people often refer to them as “alkaleaks”.
That leakage is unrelated to parasitic drain though.
I recommend using battery chemistry less prone to leaking: nickel metal hydride or lithium. Avoid alkaline.
does your flashlight threads anodized?
if it’s not, you’ll need to pull it off completely to break the current.
on image above, the upper part is anodized (purple) while the bottom is not (shiny).