4.49 EUR:
https://www.ttt48.de/akku/lithium-ionen/18650/molicel-inr18650-p26a-36v-37v-2600mah-lithium-ionen-akku.html
and they have still to sell 1018 peaces.

My question was, does we can compare on mooch batteries website same like on dampfakkus?
Dampfakkus has only two of the mooch best mech mod batteries and only with a drain of 5A in their list:
http://www.dampfakkus.de/akkuvergleich.php?akku1=537&akku2=498&akku3=353&akku4=610&akku5=490&akku6=&a=5
Easy to see, moochs Samsung 25R is the second best after moochs Sony VTC5A ,
same on his website.
(the other 3 are the batteries which I use).

The graphic shows, there are 2 or more better batteries than which I use.
If the price is OK, why not buy the better battery?

Years ago I was thinking about springs and magnets,
but I dont think the main current is on the spring/magnet.
With 12A on the spring, your spring would glow.