It’s good to understand how the batteries you use for vaping work, especially if you’re using them in a mechanical mod. The ins and outs of how batteries work aren’t as important if you’re using a regulated device but it can still be good to know if you’re using bypass mode in a regulated device. And battery safety, no matter how you’re vaping, is important for everyone. Read more about vape battery safety here.
Battery Chemistry and Sizes
There are different types of chemistries that batteries use, such as alkaline, which are the common types of batteries we use in most home electronics. But in vaping, we mostly use lithium-ion cells. We mainly use 18650, 20700, and 21700 li-on batteries.
These numbers stand for their size or physical dimensions. For example, the 18650 battery is 18mm in diameter and 65mm long, and the zero indicates that the battery is round. The 21700 is 21mm in diameter, 70mm long, and also round.
IMR, INR, and ICR Batteries
The li-on batteries we use come in either IMR or INR forms. The letter “I” represents lithium, the letter “M” represents manganese, the letter “N” represents nickel, and the letter “R” represents that the battery is round.
You might also see ICR batteries, which are made of cobalt. This is a protected cell, which means it has an extra layer of protection in the form of a circuit board in the battery. This limits how much current the battery can put out. While this sounds like a good feature, these batteries also have a much more violent reaction if the circuit fails. These batteries also have an output of only around 10 amps, which isn’t enough for vaping. This layer of protection makes the battery taller than other batteries too, which won’t fit in most vape devices.
How a Lithium-Ion Battery Works
There are several components within a Li-Ion cell. The most important components are the negative and positive, or the anode and cathode. The battery is wrapped in alternating layers of anode and cathode material. The battery is then filled with lithium salts and sealed in the stainless steel container. When you put a load on the battery or connect the two ends of the battery, it allows the electrolytes to pass between the anode and cathode to give you voltage.
Other important parts of the battery are the gasket and safety vent. The safety vent is located right under the cathode at the top of the battery. If the battery fails, that’s where the gases will vent.
Batteries are wrapped in insulating plastic. This is because the entire shell of the battery is the negative terminal of the battery. Without that plastic, li-ion batteries are extremely dangerous because if anything metal touches both the negative terminal and the positive terminal, such as loose change in your pocket, the battery will short and may vent or explode.
Batteries are extremely expensive to produce and they require millions of dollars of technology and equipment to manufacture. That’s why the best batteries come from brands you recognize, like LG, Samsung, Sanyo, Panasonic, and Sony. But you’re likely to see other batteries from brands like Golisi, Hohm Tech, Imren, and Efest.
When buying a battery from a brand not made by one of the major manufacturers, never trust the ratings on the label. If you need some recommendations of good batteries to buy, check out this list from Battery Mooch, who tests batteries for a living.
When a large company tests batteries, they test for quality assurance. Batteries that pass go into the A bin. Slightly imperfect batteries, such as those with dents, go into the B or C bins. “A bin” batteries are sold off to be used in laptops, power tools, and other devices. B and C bin batteries often go to smaller battery companies that don’t manufacture their own cells. These companies then put their logos on them and sell them as their own. This doesn’t always mean they are bad batteries but you should also know that there was some reason why Sony, Samsung, or LG decided these weren’t good enough to put their name on.
Using Ohm’s Law To Vape Safely
To build your atomizer within the safe limits of your battery, you need to understand Ohm’s Law.
There are calculators that can make this easy, such as steam-engine.org, but it’s important that you understand the different formulas and why they matter in vaping.
There are three main elements that go into this calculation; Voltage, Current, and Resistance.
To calculate current: Voltage / Resistance
Let’s say your atomizer is using a 0.5 Ohm coil. That’s your resistance. Your battery has 4.2 volts. 4.2 / 0.5 = 8.4 amps. If your battery is a 30 amp battery, you’re well within the limits of that battery. Important note – you never want to match or exceed the amp limits of your battery. Stay below to be safe.
To calculate wattage: Voltage x Current
Your battery is 4.2 volts and from the formula above, you now know that your amp draw using a 0.5Ohm coil is 8.4. So 4.2 x 8.4 = 35.3 watts. Is that enough watts to satisfy you? If not, lower the resistance of your coil.
To calculate resistance: Voltage / Current
This formula helps you determine how low of a resistance you can build within the limits of your battery. If your battery is a 30 amp battery, you could go a little lower than 30 to be safe, such as 25. So your battery is 4.2 volts and the current is up to 25 amps. That means you can build as low as 0.168 Ohms.
Charging Your Batteries
Many devices today have the ability to charge batteries directly within a device. In most cases, this is probably safe, but there have been instances over the years where a device’s charging safety features failed and a battery is overcharged, which can cause a battery to vent or explode. And that’s why most experienced vapers recommend using an external battery charger designed specifically for charging batteries like li-ion cells.
Smart battery chargers like the Xtar and Luc V4 can detect the type of battery you’re using, they can take various sizes of batteries, and they charge them appropriately. They also have safety features to prevent batteries from over-charging. You also want to charge using the slowest setting on your charger to put the least amount of stress on the battery.
Voltage Drop / Battery Sag
Voltage drop isn’t going to impact most vapers but if you’re using a mechanical mod, this is good to understand. Li-ion batteries have a max voltage output of 4.2 volts. But because of voltage drop, you don’t actually get that full 4.2 volts.
When you put a load on a battery, it immediately gets what’s called “battery sag”. This is because batteries struggle to put out the full voltage while it’s in use. For example, your battery might read 4.2 volts on a multimeter while not in use but once you start drawing power from it, it might sag 0.35 volts. So while firing, you could be drawing 3.8 volts, rather than the full 4.2. This depends on the device you’re using, the atomizer resistance, and the materials those products are made from.
Parallel vs Series Vape Battery Configurations
In a parallel setup, multiple batteries are connected in a way that makes them act as one larger battery. This works by connecting the positives to each other, as if they’re side-by-side, and then separately, the negatives to each other. The overall voltage remains the same, so they’ll still put out 4.2 volts but they share their amp limit. So if they are both 30amp batteries, they can safely push 30 amps or more. In an ideal world and if there was no resistance along the path, you could double the amps, but because the connecting wires have resistance and there are other inefficiencies along the path, parallel batteries aren’t able to be fully combined. A good rule of thumb is that you can get 1.5 times the limit of the batteries. So two 30 amp batteries are safe to push 45 amps. Another benefit of running batteries in parallel is that the mAh is combined, so you get longer life as they’re used.
In a series setup, multiple batteries are connected to each other in a line, as if they are stacked. So the positive end of one battery is connected to the negative end of the next battery. The voltage is doubled in this type of setup. So two 4.2 volt batteries will now have 8.4 volts. That gives you more power.
Batteries only have so many cycles before they die. That’s why it’s recommended that you pair, or “marry” your batteries together. This is more important if they’re being used in a dual-battery device. So if you know you’ll be using a dual-battery device, use an already married pair of batteries or buy a new set of batteries and always keep them together for dual battery setups. Or if you swap them in single-battery devices, try to keep them charged around the same number of cycles.
This isn’t a strict rule but it’s a good one to follow to make sure each battery in that pair is run and charged together and for the same number of cycles. This prevents you from mixing your batteries and using an old cell with a new cell, which can cause performance issues as that old cell begins to die.
The Inner Workings of Vape Batteries
And those are the basics of how the batteries we use for vaping work. For the hobbyist vaper, such as someone getting into mechs, this is extremely important stuff to know. But no matter what type of vaper you are, it’s good to understand the more technical details of li-ion batteries because it’ll help you stay safe and also help you get more out of your batteries to get the best experience possible!