@Narkis always check your coils ohm's with a ohm meter twice once after building then again when you replace the cap. If the readings differ then the coils are touching the cap or the cap has pushed them onto the deck . Most of the rest has been said.
My last point is you do know a mech using a 20 amp battery won't push as much power as a 200w regulated mod. I say this as some folks think a mech will create more vapour. Oh and a mech will require regular cleaning of the threads and contacts. One more thing a series mech would be a daft start point so stick to a tube or duel paralell box for a while.
