# What is an E-Cigarette mAh / How to Choose E-Smoking Device Batteries and Puffs per mAh

**What is Battery mAh?**

mAh stands for milliampere-hour. It is the standard of measurement that describes the total amount of energy that an object such as a battery can deliver over one hour. For example, a battery with a rated capacity of 1000 mAh could deliver 1000 milliamperes — or one amp — for one hour before its capacity is exhausted.

**How Does mAh Affect E-Cigarettes?**

The mAh rating of your battery can help you calculate how long your battery will last, but only if you know the number of amps required by your e-cigarette to keep it working. That means you need to know how much juice your battery and atomizer or cartomizer draw when in use.

For example, consider the typical e-cigarette with an atomizer rated for 2.5 ohm and a 3.7 volt battery. You’ll be drawing 1.48 amps per hour when e-smoking, which means that you’ll need to recharge a 1,000 mAh battery after a little more than 40 minutes of use. Bear in mind, though, that this is only true if you chain smoke. If you puff on your e-cigarette a few times and then set it down for a while between uses, you can easily spread 40 minutes of active smoking time throughout an entire day.

If you’re using a battery with a different voltage or attachments that may have a higher or lower resistance, then you can calculate the amount of base amps being drawn by using an Ohm's Law Calculator. You’ll end up finding the drain in amps, so multiply by 1000 to get the milliamps.

It’s a bit tricky to calculate the exact drain that atomizers and cartomizers place on a battery. The resistance they offer can vary as much as 0.2 ohms less or more than they’re rated for when it use. This makes calculating exactly how many puffs you’ll get from a fully-charged battery difficult, but you can still arrive at a fair estimate.

**Calculating Battery Life**

To find out how long your e-cigarette will last with a particular battery, you need to take a look at the battery life calculator one calculator can be found here Battery Life Calculator. Enter the mAh rating of your e-cigarette battery or the battery you’re interested in.

Then, take the standard value of 1400 milliamps or the value you found during the previous step using the Ohm’s Law calculator enter the “Consumption of Device” field.

You can then click “Calculate” to get an idea of how long your battery can be expected to last in hours. Unless you have a very large battery, you’ll likely end up with a result that is a decimal value like .132.

You can then take this value and multiply it by 3600 to get the number of seconds that your e-cigarette’s battery can last.

The value you find will be the total number of seconds that your e-cigarette can produce puffs. If you follow the example value of .132 hours, you’ll come to 475 seconds after making these calculations.

**Estimating the Maximum Puffs of an E-Cigarette Battery**

The last step in making use of the mAh rating of a battery is to estimate the total number of puffs that you can get from it before it runs out of juice.

To get this, you divide the total number of seconds you obtained in the previous step by the time your average e-cigarette puff lasts. That means if your average e-cigarette puff is about 3 seconds, you’ll end up being able to take 158 puffs before you need to put your battery on the charger.

Just keep in mind that the amount of puffs you’ll get from your e-cigarette will likely vary from your calculations. It’s our experience that the number of puffs you tend to get will be higher due to the voltage dropping as you use it.