Sub-Ohm Vaping - A Guide
What is Sub-Ohm Vaping?
Simply put it is vaping on a device whose atomizer coils have a resistance of less than one ohm. The reason some advanced vapers “sub-ohm” is to increase the power output of fixed voltage devices like mechanical MODs and non-variable regulated devices to create more vapor or flavor.
Although it might sound simple it’s actually a complex and often controversial topic within the vaping community. The goal of this guide is to make sure you have accurate information so you can decide if sub-ohm vaping is right for you.
BUT WE DO NOT APPROVE OF NEW VAPERS SUB-OHMING!
We believe vapers should take their time and learn the craft of wrapping coils, battery amperage, and proper safety before you even think about sub-ohming, especially below 0.5 ohms! I know many of you will not listen to this though so this article is for those people, people who are interested in sub-ohming, or even people just wanting to know what it is.
How Does Sub-Ohm Vaping Work?
All mechanical mods, VV/VW regulated mods and e-cigarettes are electrical devices powered by a battery. Sub-ohm vaping utilizes the principles of Ohm’s and Joule’s laws of electricity. For our purposes this means, a non-variable voltage source like for instance the battery in a mechanical MOD will increase the overall power output (wattage) of your device when you decrease the resistance (ohms) of your coils. It is absolutely crucial that sub-ohm vaping must be done safely.
As you decrease your resistance you will increase the amperage your device uses to supply the current needed. This increases the strain on the battery and also increases heat from the battery and coils. If the battery can’t handle the draw of these amps then it will overheat and run the risk of popping.
For this reason you must ensure that you never exceed the amperage limit of your battery or it could fail causing possible fire or explosion.
The Sub-Ohm Tank War
Are we about to see something rather revolutionary?
Aspire and Kanger, two of the most influential e-cig manufacturers, have been working hard to transform the concept of the traditional clearomizer. The majority of consumers will use a tank, of some kind, on a daily basis. The benefits on the tank are clear: They are easy to use, maintain and are mostly hassle free. They compliment most batteries, although some may need an adaptor, and are suited to all levels of vaper; from beginner to veteran.
That said, the humble clearomizer cannot compete with the more complex rebuildable atomizers (RDA) on vapour production and, at least to the majority of people, taste. Those who have an interest in the e-cig world will surely have seen, or at least heard, of the RDA. All those big clouds, the culture of the cloud-chaser; they all stem from the intricate RDA. They are favoured among what we may call the more ‘hardcore’ vapers, those who see vaping as a hobby as well as an alternative to cigarettes. As we know, vaping is as much a lifestyle product as a cessation device.
But unless you were interested in the rebuildable world, you would have missed out on the benefits of the RDA. Perhaps, no longer. Kanger and Aspire, who have both made announcements within a day of each other, unveiling new tanks (Subtank and Atlantis - end 2014) with the capability of matching the performance of the RDA. Aspire boldly claiming that it is “Game over for the pro Vapor cloud chasers”.
The Aspire Atlantis Tank and the Kanger Sub Tank, which will both be available to purchase soon, are perhaps the future of the vaping world. But what is it about these tanks that will be so different?
The atomizer heads (or coils) are the biggest difference. With RDA’s the resistance of the atomizer is lower than with the atomizers used in traditional clearomizers. With a higher power battery, and lower coil resistance level, you will see an increase in vapour and more intense flavour.
The Aspire Atlantis will utilize 0.5ohm resistance coils – a resistance level which is common with typical RDA set-ups. In theory, we should be expecting similar performance from the new tanks in comparison to an RDA, with the added bonus of not having to rebuild coils, wicks and drip juice onto the wicks. Essentially, doing the hard work for you. Although, The Kanger Subtank will allow users to rebuild the coils should they so wish. Once we get hold of these, we will be able to go into more detail on what it is that makes them so good.
Of course, it is not until these tanks hit the market that we will not know for sure whether they can truly match the RDA. And it can’t be too long till we see other manufacturers producing similar devices, especially if these tanks prove successful. It’s an exciting time in the e-cig world!
The Sub-ohm clearomizers are here to stay!!
Early 2015 other manufacturers have launched their version of sub-ohm clearomizers, and almost every week a new sub-ohm clearomizer hits the market. Not only do these sub-ohm tanks offer prebuild coils down to 0.2 ohm, but also many manufactureres have developed powerfull VW/VV devices which can actually fire these Sub-ohm tanks. So our conclusion is that Sub-ohming is becomming more and more common for normal vapors, since these VW/VV devices offer the build-in security which is so important to focus on.
- Kangertech: Subtank, Mini Subtank, Nano Subtank
- Aspire: Atlantis
- Smoktech: VCT Subohm Tank
- Joyetech: eGo ONE
- Horizon Tech: Arctic Clearomizer
- And more to come
But are you the hard core DIY hobby vaper ?
But perhaps you're still think that Making your own Sub-ohm builds gives better flavor and taste and that you really enjoy climbing up the learning curve of making these Sub-ohm builds, then continue reading below, so that you take the correct safety precautions, and know what you're doing and why, so that you avoid an accident with your battery.
Is Sub-Ohm Vaping Dangerous?
Is sub-ohm vaping dangerous? The honest answer is yes and no. When some basic safety rules are followed sub-ohm vaping is quite safe. If these safety rules are not followed your battery or device can fail resulting in injury and/or product damage from fire or explosion.
E-liquid, Nicotine and Sub-Ohm Vaping.
When vaping using sub-ohm coils a substantial amount of vapor is produced compared to using coils above 1ohm on the same device. Typically sub-ohm vapers take lung hits meaning they inhale straight to their lungs increasing the vapor they can inhale in each puff. Those who vape sub-ohm usually favor e-liquid with a higher percentage of vegetable glycerin than propylene glycol. The reason for this is that the vegetable glycerin creates larger clouds and a denser vapor production. This is because VG has reduced throat hit compared to PG which helps to accommodate for the increased amount of vapor inhaled. Usually those vaping sub-ohm will also use lower nicotine strengths (typically 6mg/ml and under) compared to those vaping above 1ohm. This due to the additional vapor produced and inhaled in each puff.
Sub-Ohm Vaping with VV/VW Devices.
Although it has become quite popular for people to use variable voltage/wattage devices for sub-ohm vaping it is actually unnecessary. Sub-ohm vaping evolved as a way to increase power to the coils beyond what the safe capacity of regulated devices available at the time. Today high power regulated devices are widely available that can deliver a consistent amount of power to the coils allowing you to use the resistance of your choice and the ability to adjust it to your liking while potentially out performing the capacity of even a sub-ohm build on a mechanical mod. While low power regulated devices remain best suited for resistances above 1ohm.
Sub-Ohm Safety: Mechanical MODs
To ensure safe performance you will want to always make sure you keep your mechanical MOD clean. This includes all threads, vent holes, contacts, and the switch. If using a spring loaded switch be sure to take notice of how stiff it feels, if over time your spring seems to be getting softer or feels easier to press it is beginning to “sag” or wear out and needs replaced before it fails. If you are going to replace your spring in your switch you should strongly consider upgrading to magnets. You will also want to be sure that you use your mods locking mechanism when it is not in use.
When selecting a mechanical MOD for sub-ohm vaping there are a few things to consider. You will want to select a MOD that is well vented. These vents allow heat to escape from normal use but also allow gases to vent in case of battery failure. You can’t have too many or too large vents for your MOD.
NEVER USE AN UNVENTED MOD TO VAPE SUB-OHM. You will also want a MOD with low voltage drop. Voltage drop is the amount of voltage lost when the electricity travels from your battery through your device and to your coils. For this reason the most preferred are MODs that feature a single piece tube, fixed position contacts, and magnetic switch. Spring loaded or threaded contacts, multiple piece tubes, or telescoping tubes might be convenient but will raise voltage drop. While spring loaded switches can wear out quickly or fail.
- Always make sure that there is a lock for the firing pin/button. The most common are those that are reverse threaded and require an unscrew to lock the firing pin/button. You don’t want to fall asleep with your mod firing continuously, after all, do you?
- Check your mod for air-holes. While there aren’t any batteries in the mod, blow into it from the connection end. Make sure you do this with the firing pin both in the locked and unlocked positions. Air holes (aka vents) are incredibly important in letting gases escape your mod if the battery is compromised. Air holes are your friend, make sure they act like it.
Sub-Ohm Safety: Batteries
When you go sub-ohm your batteries are the most crucial component of your setup. It is of the utter most importance that you select the right battery and use it safely. Although we will only touch on the subject here.
The very basics: Never expose your battery to water, extreme heat or cold. If the wrapping on the batteries becomes damaged simply stop using it. If your battery is dented in any way discontinue using it right away.
When sub-ohm vaping you must carefully select your battery. You must make sure it is an authentic battery from a well-known brand and a store you trust sells authentic products. For sub-ohm vaping use unprotected IMR or hybrid lithium batteries. These batteries have a “safer” chemistry inside, so in case the battery fails it vents gasses more slowly lowering the risk of fire or explosion opposed to traditional Li-ion, LiPo, or ICR battery types. Usually sub-ohm vapers prefer batteries with the highest possible continuous amperage limits. This because it’s important that you stay within your batteries amperage limit in order to be sure you sub-ohm safely. By taking your batteries voltage (4.2v fully charged) and divide it by your coils resistance you find out how much current your device / setup will draw.
For example 4.2v / 1ohms = 4.2A discharge rate while 4.2v / .5ohms = 8.4A. and 4.2v / .2ohms = 21A. Make sure always to use an Ohm meter to be sure there are no shorts and to check your resistance before you vape. Since if your resistance is wrong your amperage calculation will also be wrong.
Remember it is absolutely critical that you NEVER EXCEED YOUR BATTERIES AMP LIMIT or it is almost certain your battery will fail.
- Make sure your batteries aren’t overcharged or undercharged by checking their volts. Always check battery voltage when you think they are getting close to needing a recharge. If you use them too often at too low voltage you will shorten the battery life. Check coil resistance with your ohm meter any time you change or build a new wick and coil. If you draw too many amps from your battery, you will have a serious safety issue as explained with the calculation above. And always be aware of the MOD’s temperature during use. If it’s heating up something needs to be resolved, or it can become serious! Always make sure to take action before an accident happens.
- Do not leave your batteries in any charger without supervision. Make sure that you are able to see or check on the charger every 15-30 minutes. This way when the charger indicates that the batteries have been fully charged, you can remove them from the charger. Leaving batteries in a charger all night long or longer can cause them to be overcharged, which can result in battery failure. Make sure not to charge your battery over 4.25 volts. This will shorten its life-cycle and going over 4.5 volts can cause it to burst. Stop using your charger if this ever happens. We suggest helping yourself by purchasing a high quality charger with the following features: - overcharge protection, - charging status indicator, - Volt indicator etc.
How to read a battery specification:
- Example: IMR18650-1600 Specifications
- Nominal Voltage : 3.7V
- Capacity : 1600mAH
- Lowest Discharge Voltage : 2.50V
- Max. continuous discharge rate : 15C
- Standard Charge : CC/CV ( max. charging rate 4.5A )
- Cycle Life : > 500 cycles
- Operating Discharge Temperature : -10 – 60 Degree Celsius
Determining Your Maximum Discharge Rate
The most important specification to pay attention to is the “Max. continuous discharge rate” for each battery. Each battery has a number and a letter, either measured as A or C (30 Amps or 15C). Look at the IMR18650-1600 for example. If your battery has a maximum continuous discharge rate of 15C, this means the battery is rated for 15 times the capacity of the battery measured in amps. So a battery that sits at 1600mAh, which equals 1.6Ah will have a max continuous discharge rate of 15 X 1.6 = 24A. You should always determine what your max continuous discharge rate is in Amps (which many batteries already have printed on the battery).
How To Use This Information Effectively
Knowing the max discharge rate in amps is only half the battle. How do you know if your coil won’t short circuit your battery? Simply, use this equation: battery volts / the ohms resistance of your coil = your actual discharge rate. If your actual discharge rate is less than the maximum discharge rate you calculated earlier, you’re in the clear. If it’s not, you have to rebuild you coil to a higher resistance coil.
Let’s take a closer look using the 18650 1600mAh battery again (for the sake of continuity). If you take a newly charged 18650 1600mAh battery and used it in your mechanical MOD with a very limited voltage drop, and made a 0.2 Ohm coil build on top, your setup will be running at 20 amps. To calculate this, you take the voltage running to your coil from your battery, which lets say is measured at 4 volts after a full charge. Now, divide this figure by the ohms of your coil. The number you get is your total amps. In this case our math is 4/0.2 = 20. So we now know that running this exact setup will push our battery to 20 amps, which is 4 amps under its max discharge rate. If you were using a battery with less power under the same circumstances, you would risk battery failure and an accident might happen.
Safety PSA: Resistance in coils can have a variance of 0.2 Ohms in either direction, or +/- .2 Ohms. This means that if you build a 0.2 Ohm coil, you have to account for that +/- 0.2 Ohm variance. So the coil in the above example at 0.2 Ohms is an incredibly unsafe coil, and I would not use nor suggest that anyone use such a coil. Because of this, I would not recommend anything lower than a 0.4 Ohm coil for 18650 1600mAh battery. If you anyway decide to use such a low ohm coil, you have to make sure your ohm meter is measuring with very low tolerances or you risk an accident will happen.
Let’s take a look at everything you’ll have to calculate in order to determine your coils safety in order
Calculate your battery’s capacity in amps: capacity in mAh / 1000 = capacity in amps
Calculate the maximum discharge rate if measured in C:maximum discharge rate = (battery capacity in amps) x (continuous discharge rate)
Measure your battery’s volts with a multimeter.
Measure the Ohms of your coil and subtract .2 to account for the +/- .2 variance.
Calculate the discharge rate you’ll have with the coil you’ve built: battery volts / Ohms = your actual discharge rate
Check to make sure that the actual discharge rate is LOWER than your battery’s maximum discharge rate.
Is Sub-Ohm Vaping Right For You?
It very well might be, then again it’s not for everyone. Before you rush off to start vaping sub-ohm please consider the following. Most sub-ohm vapers are quite dedicated and experienced. It requires assuming a certain amount of risk and therefore takes diligence and care to do so safely. If any of the above sounds like it might be undesirable to you or if you think you would be unable to follow the safety rules please do not vape sub-ohm. If you are dissatisfied and need more vapor or flavor than you get vaping at resistances above 1ohm, consider a high powered VV / VW regulated MOD. We do not say this to discourage you instead we do it because we care about your safety.
If after all this, sub-ohm vaping still sounds like something you are interested in, please contact us so we can help you to get everything you need to sub-ohm vape happily and safely.
All the above can be summarised in the following Youtube Video:
Understanding Sub Ohm & Vaping Smart, Battery Safety, Ohm's Law, Voltage Drop
If you based on the above input have decided that sub-ohm is still the road you want to follow, then you just need to learn how you actually make a sub-ohm build.
How to make an RDA sub-ohm build on a mechanical MOD
Coils are the basic part of a sub ohm build. They are what actually provides the heat to vaporize the liquid. Think of coils as resistors, they carry the electrical current through the atomizer in order to generate heat which then vaporizes the liquid, the resistance of the coils determines how hot they get and how quick. A higher res coil is going to take more energy and time to get red-hot, where as a low res coil is going to generate more heat and pull more amps from the battery. That being said the lower the resistance the quicker the battery is going to drain and the more strain there is on the battery.
A coil is made using Kanthal wire that is wrapped around a screw driver, drill bit, or wick, in order to get a certain diameter in order to get the right resistance. Depending upon the length of the wire and the number of wraps on the coil than resistance is going to go up or down, its your job as a sub-ohmer to figure this part out because only you know what your target resistance is. In order to figure things like wraps or length there’s different tools available on the internet.
If you’re looking to start building you need several things, some of which are purely to make the process a bit easier for you.
For one you need the most important thing, kanthal wire. The size of the kanthal is going to matter. Kanthal comes in different gauges and depending upon the resistance you’re looking to get you will want to change or modify the gauge and / or the number of wraps you need to get to your target resistance. 26 gauge as it’s a well-rounded number and requires a minimal amount of wraps to reach my usual target of around .5 or .4 ohms.
After the wire you need your wicking material, this can come in several forms from silica, ekowool, cotton, steel mesh, and several other wicks although the previous four mentioned are the most commonly used.
As far as what is the most available that would probably be the cotton, its cheap and can be bought practically anywhere, just make sure that it is 100% sterile organic cotton, meaning no bleach or pesticides.
You will also need some tools, these tools mainly help in fine tuning your coil or help in its production. Precision screwdrivers are nearly a must for this kind of work, they make getting the small screws of the RDA out an easy task, and provide a good wrapping post. After that, you need some needle nose pliers or tweezers, a torch to clean the wire and silica, batteries that can withstand your ohmage to test fire with, and most importantly… an ohm meter. Oh and patience, don’t forget that good old patience.
Here you have a safety chart for Sub-ohm vaping: