There is a standby drain due to the electronic switch, which is reasonable at just under 9 months for an Eneloop Pro AAA. Locking out the light electronically should lower this drain and allow a battery to last longer. The stainless steel build tested here cannot be physically locked out, as anodizing is not possible. However, I expect the aluminum build would have this feature.
As we are hearing, the
alu build can be physically locked out yes.
Unlike drivers of
other 1×AAA SS (or Titanium) flashlights, on the K18 SS the driver disc is
not electrically insulated against the SS head. :huh:Actually this electrical situation is due to the installed/screwed
brass retainer crown which is to hold the driver disc in place AND serve as physical reverse polarity protection (RPP) at the same time.
Today i wanna talk about the RPP (and next time i'll talk about the standby current drain).
The stepped brass retainer ring ("crown", "spacer") has an inner diameter of Ø10.00mm, easy to measure. In theory, it spaces AAA battery bottoms ~1.0mm away from contacting the metal(+)contact of the driver disc; on the
2019 SS model the clearance is more like
~0.5mm because it has a raised metal(+)contact. There are two potential issues with this idea/design of physical RPP,
depending on the AAA/10440 battery model you insert reversely.
case1) If the battery is thicker/wider than Ø10.00mm AND the battery bottom is bare, i.e. not partially covered by heat shrink wrap/tubing/sleeve material or alike, then the reversely inserted battery gets
short-circuited, as soon as the SS body touches the SS head. Shorting a fully charged battery can be hazardous, bye-bye battery
A commercial example would be your standard Eneloop AAA battery, it has a bare bottom. Another commercial example would be blue unprotected UltraFire TR10440 (600mAh 3.6V).
case2) If the battery diameter is less than Ø10.00mm, say Ø9.8mm, then the battery bottom will(!) contact some part of the driver disc and eventually, depending on the battery model and the K18 SS version, electrically contact the metal(+)contact in the center of the driver disc, thus leading to an
established reverse battery connection, bye-bye driver
A commercial example would be
(fake?) Panasonic AAA Alkaline, which comes in at Ø9.65mm om*g. So yes —
and feel free to check with all AAA/10440-sized batteries in your household— batteries slimmer than Ø10.00mm do exist and that is a reason of concern.
My point being, only because the K18 SS is advertised as having "Reverse polarity protection", in general you should
NOT just go ahead and mindlessly insert
any AAA/10440 battery reversely for fooling around or testing/trying to understand the RPP. The good news is that some/many batteries, for example the
originally included noname blue unprotected 10440 battery, has a thickness of Ø10.2mm AND not a bare bottom, so neither case1 nor case2 comes into effect yay! :naughty:
The "unnecessary" mod. There's nothing much we can do to mitigate case1, hopefully you realize fast enough when you have reverse-installed a blue UF10440 or Eneloop AAA; at least you didn't wreck the driver haha. But we can eliminate case2 by installing a plastic spacer/donut/ring, as
we did for the LD01 SS before:
Here a modding advantage, the conductive brass retainer ring serves as centering aid for our purpose
nice thanks and we can :thumbsup: friction
press-fit the plastic spacer without the need of glues, adhesives, or tapes, hooray:
Shortcoming:
Ultratac's idea of physical RPP is a ~1.0mm (
~0.5mm) spacing brass ring and maybe they should have tested an inner diameter of Ø8.50mm to mitigate case2. Ch*nese batteries with w*ld (+)pole assemblies exist, see photo above, so making a spacer out of brass isn't the best idea to start with, because a reversely installed battery could get easily shorted. The advantage of brass is that it is permanent material/installation unlike a taped foam donut lol, and that we can use it for press-fitting a plastic spacer (to mitigate case2). In the end imho it is better to have this brass solution (which can be enhanced with the shown plastic mod) than not to have any physical RPP. Just keep in mind that the original K18 SS RRP is not watertight (see case2) and that case1 is still a potential hazard. By comparison, my modded LD01 SS has no potential issues with case1 or case2 but it has a realistic other potential issue, namely
losing the plastic donut spacer because of failing (weak/strong) adhesive! On the K18 SS, you will never lose the press-fitted plastic donut spacer and you will never lose the brass ring, because they are "perma-installed". Maybe that was the main reason why Ultratac decided for a brass solution instead of a foam donut solution. However, imho they should have tried brass rings with 8.00, 8.50, 9.00, and 9.50mm diameter, because obviously 10.00mm wasn't
the optimal choice.
