I also saw some youtube video about a smaller cell in a pvc tube. I though about it; why put more weight in it than the original; i would aim for 45-46gram not 81grams.
I’ve got now 4 batteries at exactly the same weight. The small battery from this video was under 200mah; i did an slow test (@300mAh current); and got those results; 1794,1703,1676 and 1674mAh. So a small battery at 1800mAh is even more weird.
I opened up an dispute at Aliexpress; i gone followed the steps The Miller gave me. If Aliexpress doesn’t decide in advantage of me i gone look for more evidence (need to open op battery). With this evidence i gone make a clear youtube video about it to warn more people. Also in the feedback at aliexpress i will point to this video; and leave a picture of the product including fake/ danger (added with paint or photoshop).
I googled manytime to find some info about other brand 18650 around 80grams; i found some advertisement of other batteries at 81grams (2.74 oz). Found even a advertisement with an LG 18650 HB2 (1500mah) at 3oz. But also weird thing is the LG HB2 should be around 45-46gram; this is probably also a fake one.
I wait on the dispute; to finish; I always can unwrap the battery and gone look for info on steel casing of the battery. But opening a 18650 battery is for me like defusing a AID (roadside bomb); i don’t know how and probably will kill myself? If their is someone that knows what he does on this forum; i will send him a battery for free to defuse. Maybe their is someone with the right equipment here that wants to test those batteries. I’m very curious what the have send me.