Head's or Tails? (bottom and top coils)
With so many different versions of e- cigarettes on the market and the huge variety of add-ons available, it is easy to get lost and confused about exactly what is what. At present the most popular type of electronic cigarette is the clearomizer tank, which is usually attached to an eGo battery or an advanced variable voltage/ variable wattage device. There are many different kinds of clearomizer tank out there, but today we are covering one of the main differences between them.
Top Coil, or Bottom Coil; which to choose and why are they different?
When it comes to picking an electronic cigarette there really is no definitive answer as to which is best. The thing to aim for is which is best for you, as we are all different and we all like different things. Here at SmokShop though, we are doing our best to help you make an informed decision about your purchase, so we are going to break it down for you and explain the differences between them and the positives and negatives of each.
The main difference between top and bottom coils is as the name suggests, one is placed at the top of the tank and the other placed at the bottom. Typically a top coil atomizer head will be attached into an extended connection that sits about three quarters of the way up the tank, and is then sealed by screwing down the top of the tank. A top coil usually has wicks that extend from each side of the tank by about 2cm and sit in the e-liquid, feeding the e-liquid up and into the coil.
A bottom coil atomizer is placed into the base of the clearomizer and makes direct contact with the positive connection on the battery. As a bottom coil is placed at the base of the clearomizer the e-liquid sits above it, meaning it is constantly fed by the e-liquid and getting a helping hand by gravity. When it comes to wicking, bottom coil atomizers have very small wicks that barely stick out of the atomizer head, as they do not need the longer wicks to feed the correct amount of e-liquid to the coil.
The advantages of a top coil clearomizer are that as the coil is placed at the top of the tank closer to the mouth piece, there is an increase in the temperature of the vapour being emitted by your e-cigarette, which many find to be a closer representation of the heat provided by the smoke from a traditional tobacco cigarette. As the coil has longer saturated wicks some find that you can apply a little more power to them than a standard bottom coil, without as much risk of burnt hits from the atomizer. Flooding is far less likely in a top coil tank as the e-liquid is wicked up to the coil from the tank, as opposed to being submerged in the e-liquid.Disadvantages
The disadvantages to a top coil clearomizer tank are disadvantages that are typically addressed by a bottom coil design, such as wicking issues. When a top coiled tank is not completely full you can get dry hits as it struggles to wick. This typically starts at around half of a tank of e-liquid, and the best way to combat this is to hold your e-cig horizontally and roll it between your fingers for two or three seconds, which helps aid wicking.
As the atomizer head is not integral to the deck (like a bottom coiled tank), the e-liquid capacity tends to be around 0-2ml less than in an equivalent sized bottom coil tank. Another disadvantage of a top coiled tank is that if an atomizer head were to blow while you have e-liquid in the tank, you have to completely empty the tank before you can replace the coil, meaning you may waste e-liquid and is a fairly inconvenient and tricky thing to do while on the move.
The advantages to a bottom coiled tank are that they avoid the wicking issues that come with a top coil system. As the coil is submerged into the e-liquid wicking issues that many top coil clearomizers suffer from are a thing of the past. As the coil is placed into the base of the unit and the tanks are filled from the bottom, the tank is easier to fill and the atomizer heads are easier to change. Even if you have a tank full of e-liquid you can typically gain around 0.2ml-0.4ml tank capacity over a top coiled design.
Another benefit to a bottom coil is that as the coil makes direct contact to the battery, the power transfer is more efficient than a top coil. You do not need to use as much power with a matching resistance, meaning you are gaining an extended battery life as well as a decrease in e-liquid consumption.Disadvantages
There are some disadvantages to a bottom coil design and one of the main issues people can face is flooding of the atomizer. As the coil is submerged in e-liquid preventing flooding can be difficult. There are varying factors in your e cigarette such as the thickness of the e-liquid. Some e-liquids can be considerably thinner than others and this can present a flooding issue to a bottom coiled tank. Another thing that can cause flooding is taking short and sharp breaths which pull e-liquid into the atomizer, which can result in flooding. It is very important to take longer and softer pulls with a bottom coil tank which is a problem that a top coiled clearomizer doesn’t have. Another potential issue with a bottom coiled tank is that as the vapour has a greater distance to travel and the tank is typically run at lower power settings, the vapour can be a medium to cool temperature which may not be to everyone's liking
We here at SmokShop would always recommend that customers try each type of tank for themselves, to enable them to see which style best suits their preferred vaping methods and set ups.
It can be a complicated journey finding the perfect e cig set up, but a very rewarding one when you get there. As always feel free to drop us a comment on any thoughts or feedback you may have.
Author: Kevin Ewbank
Avid vaper & co-founder of SmokShop