Ok, so you’re looking at building your own coils and you need to know the wattage to set your mod at to fire at the optimal setting, getting the most out of your new masterpiece. Well just hold your horses a little. You’ve clicked on this video because you know that there’s some learning involved with this. We’re going to take a look at Ohm’s Law, why it’s important in coil building, understanding the calculations and finally, how to apply it to the coil building process to ensure that you do everything safely. So it’s back to school, let’s get into it. Ohm’s Law, is a law stating that I know. You feel clever already, right? To paraphrase, Ohm’s Law is a formula to help you work out the Ohms, Voltage and the Amps of an electical current. If that still seems a little too complicated, remember as a vaper, you’ve already been adjusting some of these since you started vaping. If you’ve had an e-cig with more than a single button to fire, you’ll have been adjusting the wattage or the voltage depending on the coil in your tank. You’ve no doubt also used a few different coil resistances. Take Aspire’s tanks for instance; these come in the box with two different coils, of two different resistances… the Ohms. We made a quick video regarding how resistance works in a coil. Check it out in the link below if the term ‘Ohm’ is alien to you or if you really just want to start right at the beginning. What you need to do when making your own coils, and what we’re looking at today, is putting those Ohms into context. Ohm’s Law’s formula is this, V, I, R. ‘V’ is the voltage, ‘I’ is the current or the amps and ‘R’ is the resistance or the Ohms. If this triangle seems familiar, you may be thinking of the well-known triangle of Speed; ‘Speed is Distance over Time’, or DST. Adding the multiplication symbols here you can see that to find the Speed in that equation, you divided Distance by the Time of travel. In the same way, to find the current/the amps (I), you divide the Voltage (V) by the resistance (R). Stick with me, we will get to some numbers. Continuing with this triangle, to find the resistance, we divide the Voltage (V) by the current (I). And finally, to find the Voltage, we multiply the Current and the Resistance. As you can see we need two of these values to find the third and complete the triangle. When we’re making our own coils, the main thing we want to know is the voltage required to fire the coil safely and not draw too many amps from the battery. The majority of mods are variable wattage so we need to know the wattage. However the wattage isn’t covered in this equation. That’s where Watt’s Law comes in. Yes…it’s another triangle. But not yet! Are you still awake at the back? So let’s work out the numbers we can. You can get the voltage from the information on your mod’s battery. This will typically be a number between 3.3 and 4.2. For your working we’d always suggest using the highest number in the voltage range also known as the ‘Full Charge Voltage’. That would be the maximum volts, and the highest amp draw from the battery. For this illustration, let’s take that 4.2 as our voltage. So with the voltage known, next up, is the resistance. Now although you may have noticed that most mods, when firing, will give a read-out of the Ohms from the coil, we highly suggest that you use this purely as a guide and it can be handy when you’re using it to keep an eye on a coil you’ve made. However, building your own coil is serious business and we need to treat this with the respect it deserves. With that in mind, we suggest using a dedicated Ohm Meter. Make sure you get one from a reputable seller. Once we have both of those values, it’s simply a case of coming back to the triangle and inputting the numbers. Our battery is 4.2 volts and let’s just say, a hyperthetical coil we’ve just made has given a steady resistance reading of 0.84 Ohms. Looking at the triangle, we divide 4.2 by 0.84 which will give us 5 amps. Great, what now? Well I did promise you another triangle. This is the last step I promise; Watts Law. And just so you know, we have a downloadable PDF for all of this. We also have a downloadable calculator that requires you to input just two of the values and it works out the rest for you. If we’ve lost you at this point, no worries, get to the calculator through the link below and let that do the heavy lifting for you. However, if you’re happy to continue down the rabbit hole, here’s that last tri- oh hold on, this side, ‘P over IV’ I and V are familiar, we already know that ‘I’ is the current or amps and in this example we’re working on, it’s 5 amps. We also know V is the voltage and that’s 4.2. Can you guess what P is? Power. Yes, the watts or the wattage. The value we’re looking for to set our mod at. So we multiply the Amps by the Volts… which gives us the watts to fire at 21 watts. Finally! To highlight this, take a look at the advanced readout from the side of a Smok AL85 Alien Baby Mod. You can see these formulae working in tandem. When you change one of the values, in this case the wattage, both the amps and the voltage are directly affected. That’s it, you made it. Congratulations. We’ll be putting all this into practice in future videos with coil building so check out the links below for those videos as and when they go up. And make sure you’re subscribed to the channel and turn on the notification bell, so you don’t miss any of our future uploads. Don’t forget both the PDF and the calculator are available for download, links down below. Thanks for watching and I’ll see you the next one.