Explain Ohm's Law in vaping

Ohm's Law is one of the most important concepts in vaping — especially if you're into sub-ohm setups, rebuildable atomizers (RDA/RTA), or mechanical mods. It helps you understand how your battery, coil, and power interact, and most importantly, it keeps your vaping safe (no exploding batteries!).

The Basic Formula

Ohm's Law is super simple:

V = I × R

Where:

• V = Voltage (volts) — basically the "push" from your battery
• I = Current (amperes/amps) — how much electricity is flowing
• R = Resistance (ohms/Ω) — how much your coil resists the flow

Most vapers remember it as the famous triangle (cover the value you want to find):

Here are some clear visual examples of the classic Ohm's Law triangle used in vaping:

vapingvibe.com

vaping360.com

(These show the triangle: cover one letter to see the formula for the one you need.)

Why It Matters in Vaping

In a regulated mod (most common box mods/pods), the device does the math for you and won't let you exceed safe limits.

But when you:

• Build your own coils
• Use a mechanical mod (unregulated)
• Go sub-ohm (coils <1.0 Ω)

You must calculate to avoid drawing too many amps from the battery → overheating → venting → fire/explosion risk.

The most important calculation for safety is current (amps) the coil will pull:

I = V ÷ R

• Use V = 4.2V (fully charged single 18650/21700 battery — worst-case/highest current scenario for safety)
• If I exceeds your battery's Continuous Discharge Rating (CDR) → unsafe build!

Real-World Examples (Single Battery Mech Mod)

1. Coil = 0.5 Ω I = 4.2 ÷ 0.5 = 8.4 amps → Safe for almost any good 18650 battery (most have 20–30A CDR)
2. Coil = 0.2 Ω (popular sub-ohm build) I = 4.2 ÷ 0.2 = 21 amps → Only safe with high-drain batteries like Molicel P28A (35A CDR) or Samsung 30Q (with headroom)
3. Coil = 0.1 Ω I = 4.2 ÷ 0.1 = 42 amps → Extremely dangerous on a single battery — don't do this!

Bonus: Power (wattage) the coil gets: P = V × I (or P = V² ÷ R)

Example: 0.5 Ω at 4.2V → P ≈ 35W (nice warm vape)

Quick Safety Reference Charts

These charts help at a glance — showing safe coil resistance based on battery amp limits (always stay 10–20% below max CDR for safety margin!):

Here are some popular battery safety charts showing amp limits vs safe resistance:

Bottom line proverb-style: "Low ohms = high amps. High amps + weak battery = bad day. Know your CDR, build with headroom, and always use quality cells!"

If you're new to building or mechs — stick to regulated mods first. They have built-in protections and do the Ohm's Law math automatically. Stay safe out there! ??