They drop down from turbo after less than a minute I’ve found but you can double click & go back into turbo or a less lumen version depending on heat temp. They don’t get really hot like other lights can. I unscrew the tail cap so not sure how low parasitic drain gets. I think the charger has protection…hang on I’ll get the manual. The manual says nothing about reverse polarity protection with charger. It just say you ‘must’ put battery in light the correct way. It says it’s got a small parasitic drain while light is off so if not using it for longer period they recommend removing battery or unscrewing tail cap which I think should answer one of your Q’s. They are fun little lights, you can get a longer battery tube too.
Muggles know how to destroy a battery, no matter how well protected your flashlight is 
My Nano has 20 micro-amps parasitic drain when off, that drains the full battery in half a year.
About the charger: putting in a battery gives a bright red light telling that it is charging. Putting in no battery gives a bright green light. Putting in the battery reversed gives a weak green light, when unplugging the USB that weak light goes off.
This suggests that with a reversed battery the charger at least does not happily starts charging the wrong way because then I would expect the red light, and it does something different than with no battery which suggests that the wrong orientation may be detected.
But then, maybe those different colours may be randomly caused by the electronics and nothing is protected at all. At least a small battery gives a small fire 
I suggest you NOT gift LiIon lights with Low CRI to muggles…
imo it is much better to stick to AA and AAA, with High CRI
for example Lumintop Tool or Manker E02 or E03
Actually, I’ve found low-CRI seems to be what muggles prefer. They like the high output, or in the case of the nano, the high throw that low CRI led provides.
Many muggles even prefer cool-white tint to neutral or warm white simply because cool white looks brighter! ugh! 
The distinction of high-CRI versus low-CRI seems most noticeable to flashaholics like us.
Thank you all for the information! Thank you, djozz, for testing the charger behavior and thank you, CR888, for referencing the GT Nano manual.
It’s strange for me to hear how some people talk about the Nano in terms of functionality. They pick up additional pipes for him, trying to deprive him of what he was actually created for: mood. In my opinion, disfiguring it by extending it by 10440 is the same as attaching an extension cord for 2 18650 to Emisar.
That’s a great post and exactly what I’ve posted to this thread more than once! This Nano is revolutionary all it’s own. A teeny, tiny creature that goes way above it’s size for throw no matter for how long the duration.
Leave it to the “experts” here who want to change it into something it’s not by doubling it’s size and even changing out the LED. But in their defense, it’s what makes BLF what it is.
I even bent and went into the all encompassing finding out what 10440 tube that would work with it. I have to admit I have no problem with that but it’s fascinating how this thread has become into let’s make it into something it originally wasn’t intended to be and maybe it might fry the LED.
Anyway, this tiny thing completely stock is what it was meant to be. It’s a tribute to how far things have come to have such a tiny thing that can throw so far as it does. This really wasn’t meant to be an EDC but a show piece of miniature tech. Maybe not too far in the future there will be 10180 size cells that will have much more capacity.
Carry on with 10440 tubes! 
Meant to be can be from two perspectives: the manufacturer’s view or what makes sense as a BLF development.
The big GT was a BLF design made into production by Lumintop. Then Lumintop initiated the mini-GT for one 18650 and we loved that (I did). Then came the micro for 14500, loved that even more, and we all expected the next step would be a AAA-size light, we even hoped for NiMh compatibility. If then Lumintop comes with a Nano with a too short tube and a silly too small too low capacity 10180 battery, it makes sense to be disappointed. 
But if you skip the story, the Nano is a lovely little light that amazes, and Lumintop did a great job on it (except on the charger, seems a not so great afterthought when they found out that a USB-C port did not fit)
Don’t forget that when the GT nano was in development, everything pointed to a 10440 battery, then it came out with a 10180! So in my point of view is a expectation vs reality issue.
BTW I bought it anyway, but also have ordered the tube now.
Your post makes a lot of sense. I don’t take my nano out as a functioning EDC, it’s more a novelty that I surprise people with when they show interest in my lights shelf. While not the most useful light it tells the led light evolution story so well to someone, their eyes jump out of their head when they see it’s beam outside at night for the first time. I’ve got fairly big hands and want the body tube so I can hold it a bit better and perhaps with some extra mAh’s I can let my little nephews take it out for night walks. My light collection is so much better off due to this forum BLF, clever folks exploring what’s all things possible & bringing their ideas to market. I have a heap of BLF designed lights and you can tell there designed by minds wanting better, not just about making profit. I’m kinda a sucker too for short tubes, long tubes and accessories in general. I’m fairly new to led lights & this forum has taught me so much which I’m really thankful for.
Quoted for truth. Made for better, not profit. Lumintop have milked the GT and FWxx series in an unedifying fashion. The Nano was always about 10440 - they know it as we knew it. Shame.
And Astrolux doesn’t do the same thing?
MF01-MF01S-MF01 MINI
FT-02-FT-02S
FT03 FT03 MINI
and so on.
Don’t get me wrong, it pisses me off also.
does not piss me off, that is how it goes and I kind of like that.
If intellectual property rights were a thing in China that would have a serious downside, and don’t get me wrong: I do think that they are important. The BLF developments from the last 7 years (from BLF-A6 to the GT and LT1) would not have happened if intellectual property rights were respected, no manufacturer would have stepped in making our ideas into products, too risky too niche. Shamelessly using our ideas and designs into other products that make profits adds to the fruitful dynamics of BLF and manufacturers, so that at present BLF-developments can be found in hundreds of flashlights and parts. In my opinion to the advantage of our hobby.
Agree - IP would be a killer here. Betta the BLF projects would not even had happened, or if they did, at 5X the cost.
I’ll just put it here …
Now that’s interesting!
They have had this exact Nano copy up for a while…that’s China for you. What’s interesting is the light is roughly 2x the MSRP of the Lumintop original! Work that one out :person_facepalming:
If it’s a copy they’ve altered the photos to make the light look even smaller then it actually is. Of course the beamshots and the price are ridiculous. Smiling Shark rebrands flashlights to sell under their own name. It’s possible these are Lumintop OEM.
One Chinese/Taiwan source for it: https://shopee.tw/Smiling-Shark-ES01-%E5%BE%AE%E7%AC%91%E9%AF%8A%E5%B0%8F%E5%9E%8B%E8%BF%B7%E4%BD%A0%E8%80%90%E7%94%A8%E9%9A%A8%E8%BA%AB%E4%BE%BF%E6%94%9C%E6%89%8B%E9%9B%BB%E7%AD%92%E7%B2%BE%E7%BE%8E%E8%A8%AD%E8%A8%88%E7%84%A1%E6%A5%B5%E8%AA%BF%E5%85%89%E7%85%A7%E6%98%8E-i.322496167.3881400338
Interesting they call it the ES01, while the Amutorch ES01 clone (rebranded?) is called the Smiling Shark ES03.
I have a Smiling Shark ES03 on order from FT, of course I'll tear it down when I get it. Dang! The price went down since I ordered 
.
Suspect these are re-branded - there's no loyalty there, could be a supplier/sub-contractor, or who knows, all these brands could be the same company or same guy.
With really nice manicures.