E-Cig Mod Battery Safety and Ohm's Law!



14. E-Cig Mod Battery Safety and Ohm’s Law


Every battery has a limit on how much current it can provide, and if you go over this limit you’re running the risk of suffering a catastrophic failure. As with most other mod safety topics, this is particularly important for anybody using a mechanical mod. The core principle is that of Ohm’s law, and the maximum amount of amps your battery is capable of putting out, but it also has implications for when you build your own coil.



Key Points


  • Ohm’s law says that current (in amps, A) is equal to voltage (V) divided by resistance (in ohms, Ω), so you draw more current from the battery when you push the voltage or lower the resistance.
  • Each battery is rated for maximum continuous discharge current, and this figure tells you how many amps a battery can provide. The Sony US18650VCT4 (or VCT3) offers up to 30 A, making it the best option if you’re likely to draw a high current. For AW IMR batteries, the 18650 (2000 mAh) can go up to 10 A, the 18650 (1600 mAh) can go up to 24 A, the 18490 offers up to 16.5 A and the 18350 can handle a maximum of 6 A. These are likely to be overestimates, so it’s better to assume a lower limit.
  • If you don’t have access to the maximum continuous discharge current for your battery, find the C-rating and multiply it by the capacity (given in mAh) to find it, remembering that 1 A = 1000 mA.
  • Low resistance atomizers make high current draw more likely, so it’s best to keep your builds over 0.8 Ω and use a large battery where possible.


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