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Tutorial: Ohms Law and Vape Safety Calculator

Tutorial: Ohms Law and Vape Safety Calculator

Overview of Ohms Law Calculator and Vape Safety

Mechanical mods, high wattage regulated mods, rebuild-able dripping atomizers and rebuild-able tank atomizers are becoming extremely popular. Most experienced vapers quickly realize the cost savings of rebuilding and make simple RDA's / RBA's and RTA's part of their daily life. It's no surprise - for the cost of a pack of coils you could buy a year supply of kanthal wire and organic cotton - the building blocks of most vape coils built today. Additionally, self build coils in RDA's tend to produce a lot more vapor and superb flavor over traditional coils, but this post is not about that.

This post is about vaping safely and what that means. And of course out free vape calculator. Let's face it, a metal tube with a high voltage battery or a high wattage (think 150W) box mod with two is nothing to smirk at. You are putting that thing right next to your eyes, mouth and face and firing (activating) it. You WANT to be safe! Before building your first coil, it is highly recommended to buy an ohms meter. This is a device that will tell you the resistance of the coils on your atomizer. Armed with resistance (Ω) you will be able to easily figure out if your setup is safe. But first, what exactly is "safety" when it comes to mods and e-cigs? Easy, the batteries used today for most mechanical and box mods are either 18650 or 20700 series batteries. These batteries vary in Amps - amps are batteries' ability to discharge stored energy (current). When a battery is pushed above its limits, the battery can vent, which means hot chemicals exit the battery under very high pressure or the battery could blow up. Yep. It's as scary as it sounds. That's why you should never push a battery beyond its capability. You should always check the resistance of your coil and calculate the amps the coil will pull from the battery, using either the volts for mechanical mods (4.2 for most 18650 and 26650 batteries) or watts you will set your box mod to. Sub-Ohming is easy and can be done safely, as long as you follow the simple guidelines above. For those of us not in favor of doing the math on our own and converting ohms to watts in your head, we built a handy Ohm's Law Calculator in our signature easy to understand style. Notice, each variable is color coded to represent a piece on the mod below.

Vape Ohm's Law Calculator

To use the Ohms Law Calculator to ensure vape safety, enter any two variables in their respective boxes and hit calculate. If the AMPS value comes out higher than what your battery is rated for, adjust either Ohms on your coil build or wattage output on your box mod. Be sure to check out vape ohms chart in our Variable Voltage and Vaping Power Chart Tutorial.

Enter any two variables

Vape Ohms Icon
Vape Amps Icon
Vape Watts Icon
Vape Volts Icon
Vape Arrow Icon

For the mathematically and scientifically gifted out there, Ohm's Law defines the relationship between power, voltage, current, and resistance. The various possible formulas for Ohm's law are as follows. But if you are feeling lazy you can always default to our vape coil calculator for quick and easy number crunching.

Vape Ohms Law Chart Calculator


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john adrian
07.06 21:33

what best battery for Sob

Dawson Smallwood
07.06 21:32

Can i use a 0.21 coil on a pulse bf box with a samsung 25r battery

07.06 21:32

can I use a DC converter with an output current or 2a on a vape mod that I am building?

07.06 21:32

I have ohms at .18 on a variable mod. Is it safe?

22.03 09:28

To work out the amount of AMPS you are drawing from your battery you need to use this one simple equation;

I = V / R
Where ‘I’ is current (AMPS), ‘V’ is voltage and ‘R’ is resistance.

A fully charged ‘vape-safe’ battery will hold 4.2 volts. So if we have a coil that we have built at 0.5 ohms we can work out the equation as:

4.2(V) / 0.5 OHMS = 8.4 AMPS
So we can see that if we have a battery with a 25AMP rating like the Samsung 25R, we are well within the safety limits for firing this 0.5 OHM coil.

19.03 17:10

I have a capo squonker rda and i have it at 85 w and it’s says 0.39 ohms. Is this bad?

14.03 22:33

I got the pulse bf mech mod kit and I’m using a dual build .14 nichrome and 3.7v battery 18650 and the ramp is slow I want to build a faster hotter ramp but staying safe any recommendations

Walter Dempsey
05.03 20:55

Most batteries list milli amps not amps are we supposed to just move the decimal point and then call that the amperage?

04.03 23:39

I started vaping with mesh and it’s reading at a 0.19 ohms my battery are 18650 I’m using a bmi v2 I don’t want to fire my chip how can I tell the minimum ohms it can hold and how high can I have with out frying the vo chip mod pushes up 150wtts

Eddy Pickett
10.11 16:21

What’s my coil size?

21.10 18:41

im running a reloux box mod that hits 200w all the coils i build come out around .2-.3 is that fine its 7 wraps kanthat 24g. i run it at about 100w i know this is unsafe but ive had trouble finding a sweet spot on this reloux mod

13.10 17:12

20700 efest ijoy 20700 are safe at 1.5omh :) (best Flavor at 2.0omh)

11.10 11:49

Not working

15.08 11:20

Hi so this calculator is kind of confusing. I just want to know if its safe to run my single coil build at 40 Watts 6.84 volts and 1.17 ohm. I just want to know if I should be worried about it exploding or if I will be fine. I normally run duel coils but my other one looked like shit so Im running a single but want to be safe

07.08 12:19

Does the voltage of a quad battery mod multiply by 4 ( 3.7v x 4 ) or does the voltage stay the same??

05.08 23:59

Can 24g wrapped in 34g 316 Stainless Steel Clapton coils be used in Power/watt setting instead
of TC? And is 100 watts suitable in wattage mode if well within my amp pull and rating?

23.07 01:40

I’m trying to figure this out. I use a .2 coil with 70/30 vape juice. Usually burn at 55.0 watts. Is that the best for flavor or no? The store I go to for everything doesn’t know for sure. They just sell it to me is what they said. Someone please help?

07.06 14:03

i got 8loops khantal 3.5 hole and 0.67ohms and 54watts, volts 2.90, im using RX2/3, when i test fire it got burn flames came out.. how to avoid this issue, im afraid when im using this it got explode in my mouth help please T_T

21.05 14:32

i have .43ohms with 8loops 24g khantal is this safe? or should i jump to .50+ ohm

15.05 23:09

I’m currently running 0.40 ohm build on a IMR 26650 3.7 volt 3500 MHA battery is this safe I’m new to all this.

29.04 13:09

“If the AMPS value comes out higher than what your battery is rated for, adjust either Ohms on your coil build or wattage output on your box mod.”. – Quick question, adjust by lowering the wattage or adjust it higher..?

28.04 14:00

just want to ask if its safe to use my built hive coil 30ga kanthal a1 5wraps and reads 0.15 ohms on my limitless TUBE mod … thanks

10.04 21:52

Hi i bought the smok alien 220 tc and have a .12 coil in it but when it ask if its a new coil i put Y but then shows the ohms to be .14 should i change it to match the coil or does it not matter ?

28.03 11:07

I’m using a kanger subox mini…just built a dual coil reading at .2 ohms firing it at 30watts…with a goon rda…would it be safe????

Because the manual says the mod should not fire lower than .3 or maybe it says that .3 is it’s sub ohm limit???

gunadil saleh
19.03 04:19

very invormative