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Ohm Law

Posted by HB Vapour on

OHMs Law is essential if you are using or are considering using a mech mod. Understanding it will save you a ton of time, and improve your overall safety.

So let’s get started –

Firstly, a few quick pointers about your batteries

  • Make sure they are the right batteries for your mod.
    Do some research and find out which batteries are right for your mod. With so many batteries on the market it is easy to grab the wrong ones, so take a minute and have a chat with any of the HB Vapour team, they’ll be able to recommend the best battery for your specific mod.
  • Check how best to charge your batteries.
    Some mods may have a pass through which allows you to charge them via a USB cable. However, some of these USB ports will be for updating the operating system of your mod, this will mean that you’ll need to remove your batteries from the mod and recharge using an external charger. Seems simple, but we have solved many charging problems this way. HOT TIP: Charge your batteries on the lowest setting. This puts less stress on the battery and don’t leave them unattended while charging. As soon as they’re fully charged remove them from the charger, otherwise you will risk battery failure.
  • MOST IMPORTANT; Never exceed the amps of your battery.
    This is probably the single most important thing to remember about your batteries. To make sure you never exceed the amps, check the specifications for your battery, divide the voltage level of your battery by coil resistance (ohms). This will give you the amp draw of your coils. DON’T ALLOW THIS TO EXCEED THE DISCHARGE RATE OF YOUR BATTERIES.

And don’t forget to buy good quality batteries and keep them protected if you’re moving them or carrying them. We recommend using battery cases and keeping the wraps free from nicks or scratches.

Now that we have battery safety out of the way time for OHMS LAW…

OHMS (Ω) is a measurement of resistance, in vaping this is the resistance of your coils. You can measure this using an ohm’s meter (available in build kits) or on a regulated device.

OHMs Law is essentially a few formulas. They are normally displayed in a triangle, and are pretty easy to calculate with a regular calculator or your brain if you’re good at maths related things.

There are 3 main elements in any electrical circuit, (hence the triangle). They are represented by the letters V, I, and R. These letters represent

  • V = Voltage (Your battery voltage)
  • I = Current (Your amperage drawn by your coil)
  • R = Resistance (the resistance, in OHMS, of your coil)

Calculating it gives another reason for the triangle as it visually depicts the relationship between voltage, current, and resistance.


Calculate Current (or I) = V ÷ R

The current calculation will tell you the amount of current your coil will need to function at its best.

Example: If your battery is 4.2 V (volts) and your coil is .5ohms the equation is I = 4.2V ÷ 0.5Ω

= 8.4amps

Calculate Power = V x I

The power calculation will tell you the power or wattage generated at the coil.

Example: Battery is 4.2 V (volts) and your amps are 8.4 (calculated in the previous example) the equation is P = 4.2V x 8.4A = Power 35.3W

Calculating Resistance

Let say your battery has a limit of 10A (amps) and you want to determine the lowest coil resistance that you can safely run.

Calculate Resistance (R) = V ÷ I

Example: You know that your battery is 10amps, so you may want to calculate it at 9amps to give yourself some head room. You’ll also know that your max voltage is 4.2V so the calculation would be R = 4.2V ÷ 9A = 0.47Ω (ohms)

Calculating Voltage

You can calculate your voltage, though you probably won’t use this as often as your batteries should have the voltage written on the wrap, or on a sticker attached to the wrap.

Calculate Voltage (V) = I x R

The most useful calculations to you as a vaper, will most likely be Current (I = V ÷ R), Power (P = V x I) and Resistance (R = V ÷ I). The combination of these 3 formulas will help you figure out the current your coil will draw and the wattage that will result. Remember, as you increase resistance, current and power will start to drop, and vice versa.

Different wire materials will have different resistances and different batteries will require different resistances, so keep this in mind when doing your calculations. But if you’re feeling overwhelmed by all the formulas and things to remember, there are online calculators that can help. Steam-engine.org has a fantastic online calculator that will ensure you’re staying within what is safe for your mod, and batteries.

It’s important to remember that mech mods can be dangerous and should only be used when you know ohms law and battery safety. This blog scratches the surface of ohms law and by no means is a definitive guide, but it will get you on the road to being a mech mod god. And as they say practice makes perfect. The best way to help your understanding is to practice with a mech mod. We recommend asking us for help as you’re starting out. We can give you the best information and tips to ensure that you STAY SAFE.

Otherwise Happy Vaping.