First of all, if this is the Efest 18650 battery 2000mAh battery you speak of, it is only
10 amps continuous discharge rate, not 20 amps.
View attachment 357512
Amps or amperage is the actual flow of electrons (current) through our coil and what causes our coils to warm up. We adjust the amperage by raising and lowering the resistance, and by increasing or decreasing the voltage. Amperage is what’s dangerous in electricity, it’s what makes things work and causes things to break.
In layman's terms, the
mAh rating or battery capacity gives an estimation of how long a battery will last on a charge. One of the other important battery specifications is the
maximum discharge rate (
amps). The maximum discharge rate became more prevalent when vapers began building their own coils. With the natural progression of things and our extreme inner drive to produce more vapor, using sub-ohm (coils built less than 1.0 ohm) resistance coils we begin dancing dangerously close to the physical limitations of lithium ion batteries.
The maximum discharge rate is generally measured in C and indicates how much current (amps) you can draw from the battery without causing physical harm to the battery and yourself. Pull more than the maximum discharge rating and the battery becomes unstable, goes into a state of thermal runaway, and can exhaust hot gasses, large flames, or explode. Quite often, a mod's features will include terms like "battery vent holes". These holes are in place to safely guide flames away from your face in the case of catastrophic battery failure. The lower the resistance (ohms) of the coil, the more amps it will draw from the battery.
1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
0.0 ohms = dead short
As you can see above, regular factory made coils (1.5 ohm - 3.0 ohm) will pose no problem with common high drain IMR batteries with a 10 amp rating. Getting into sub-ohm vaping, the 10 amp batteries prove to be inadequate for the lower resistance ranges, and a 30 amp battery is then necessary.