I can also get the shop in my town to rewrap the batteries for free so I can have them do that to the green one. Also the top part of my green battery is dented in. Is that a problem or should it be flat like my red one?
ANY damage to a battery, no matter how slight, can become a HUGE FIERY problem.
The mAh of a battery is FAR less significant than how many amps it can deliver, because if you routinely push your batteries to their limits or above, with low-ohm coils, you are also asking for a HUGE FIERY problem.
A regulated mod is one with electronics that allow you to set your power level, either voltage or watts; a total newbie has NO business trying to use a mech and self-built coils, because there is ZERO margin for error.
GET AN OHM READER ASAP. GET NEW BATTERIES ASAP.
As for the speed of coil heating, the more metal, the longer it takes -- I use 29ga kanthal for my coils, because 28ga is too slow at my preferred power level (10w or less). The more coils, the fatter the wire, the slower it will be to respond.
Andria