Here, we will be discussing the math behind vaping and the most important safety information we all need to know.
The first and most significant topic is Ohms Law
From Wikipedia:
“…the electric potential difference between two points on a circuit (V) is equivalent to the product of the current between those two points (I) and the total resistance of all electrical devices present between those two points (R).”
The equation for Ohms Law is as follows:
V=I*R or I=V/R
V being Voltage and measured in Volts, I being current and measured in Amps and R being resistance and measured in Ohms.
Now, more than the original, most used, Ohms Law equation, we as Vapers use the Wattage and Voltage equation much more. Here it is.
W = V2 / R W being Watts, V being Volts, and R being Ohms
Here’s how it applies. You have yourself a 1.5 ohm protank, and you have it set a 5v and want to know what wattage you’re at.
That’s W=52 / 1.5
W=16.6
VV (Variable Voltage) and VW (Variable Wattage) are two different pieces of the same pie. Variable voltage means you have to know the ohm of your atomizer to be able to know what wattage you’re at. Turn the voltage up and down with a set Ohm, and your wattage (power) changes. But wattage, it doesn’t matter what Ohm your atomizer is at, it will always fire at that power.
Now, if you would like to know how many amps you are drawing from your battery, apply the numbers to the first equation
that’s I= 5V / 1.5Ohms
I= 3.33Amps
This means you are pulling 7.5 Amps from your battery.
So how do we know if we’re safe?
The amp limit of a battery exists in a few different forms. Some battery resellers will include information on the “Continuous Amp Discharge” rating of a battery; this tells you the amount of Amps you can pull from the battery while you are continuously firing your device. Even though most resellers should be psoting thses numbers, some don’t, and some do not include it anyway. I would check the manufacturers site to know the real “Continous Amp Discharge” rating.
The other form of Amp limit comes in the C rating. This involves math, and will also be explained in this Math portion of the site, but here is the general gist of it.
You take the C rating of the battery (I.E. 8C) and times it by the Ah (mAh divided by 1000 to get Ah) to get your amp limit. SO, if I have an IMR battery, that is 2100mAh, and has a rating of 8C, I have an amp limit of 16.8Amps.
The equation is as follows Ah*C=Amp Limit or (mAh*C)/1000=Amp Limit
NOW, you are going to use yoru amp limit to determine if you are in the safe zone of the batteries amp limit. You take your atomizer, with a 0.5Ohm coil on it, and a battery set on 3.7volts, you are going to have an Amp draw of about 7.4Amps. The equation goes as follows I=Current measured in Amps V=Voltage and is measured in Volts and R=Resistance and is measured in Ohms.
I=V/R I=3.7Volts*0.5Ohms
Just remember, when checking your Ohms on a Multimeter or an Ohm Meter, assume you have play room of +/- 0.2 ohms. If you’re amp limit dictates that you can only go as low as 0.5 Ohms, you’re goings to want to be safe and not go any lower than 0.6 Ohms since the REAL reading could be in the neighborhood of 0.5 Ohms. Just be careful and give yourself a little “cushion room”.
I know it may seem a little overwhelming, but it does get easier and easier.