@WakeAndVape: I heard that crackling sound sometimes, unsure what it really is... The urban legend around here seems to tell it's the bud moisture being flash vaporized, but maybe it's something else, like micro-sparks on the trigger contacts?
Hey by the way I forgot to post that very important bit of information: one morning I took my Mi, loaded a fresh stem and battery, started drawing and... effin' cold! Nothing! Tried again a few times, still cold air, very disturbing... in fact so disturbing I thought it was dead!
The previous day I dropped it not very violently but still it ended on a wooden floor. No apparent damage, but maybe something was wrong inside? Thankfully it was something else!
I had in the past a couple cases where the battery lid/contact came off its post/screw and fell with the washers etc... I had to screw the post counter clockwise to make it longer as apparently over time it can become too short and deep.
This time I dismantled everything and I screwed counter-clockwise to the max until I felt some resistance and couldn't go further. Put everything back in and then got heat on first try! So I'm not sure what's happening here, but it seems possible to get an intermittent contact here.
Previously in this thread someone said it was not normal for the trigger and battery lid to become very hot during use. My Mi always had this tendency after a good lengthy session and I was not convinced it was really a problem: after all there's a single circuit made of conductive metal and both the trigger and the lid are directly connected to the heater leads, copper being a very good conductor (both heat and electricity) so...
Still, it might be just an impression but I think my Mi is not getting as hot as before in these places now. Could it be that our units can develop some kind of bad contact in that screw/post place? There's something to investigate here, and if ever you also get a dead Mi one day, remember my misadventure!
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@WakeAndVape: now to answer your question about battery longevity, it depends if you deplete them daily or less frequently. Right now I have three in rotation dedicated to the Mi (2x 25R and 1x HG2) and on average I use 1.5 to 2 full cells daily. At this rate after about 6 months the top-end should be long gone. It's not that they don't work anymore but they just lose their ooomph.
I didn't measure exactly but it's quite possible that they now go from 4.2V directly to 3.7V under load. The more they age the more the internal resistance rises (IR) The higher the IR the more sag they have. Up to a point where technically they still work and you can still charge them to 4.2V (but it doesn't hold) but then they drop so low under load it's worthless.
Interestingly when they reach that end of life stage, there's the inverse of a sag when you charge them: say you put them at 3.6V on the charger and as soon as you apply some charge current the voltage rises very high close to 4V or more, and the charger quickly cuts at 4.2V etc, completing the CC/CV procedure etc but as soon as you remove them the voltage drops back. It's hard to explain but it's like they become "elastic" in a way... and it's this elasticity in both directions that reduces the practical capacity left.
Played w/ the fit of everything and packed it away, good to know it's ready when I am.
