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  1. *** Update 2 I just got an email from a second representative at efest, where they state that the 2000mah is 5C. Boggles my mind. 2000mah is back down to 10A.

    ***UPDATE I have recieved a reply from efest regarding the c-ratings of their IMR batteries, a topic which I know has been of debate on these forums. They clearly stated that the absolute lowest c-rating for any of their red IMR battery types is 8C. Unfortunately they did not comment specifically on the models I asked for info on. This means that the 2000 mah actually has an max discharge of at least 16A.

    Continuing on from my post on battery safety, I have compiled a list of the accepted maximum amp discharge ratings for different battery types. This has been a work in progress for quite some time. Several emails had to be sent to manufacturers in order to obtain correct data.

    It should be noted that where definitive data could not be obtained (due to Chinese new year) I have posted the lowest accepted maximum discharge rate for the battery. With more information I will endeavour to update this list as I get it.

    *NOTE! This resistance number will put you at EXACTLY the maximum discharge rating for the battery when using a fully charged battery at 4.2 volts. It is NOT advisable that you toe this line, give yourself a margin for error and safety!

    [TABLE="width: 421"]
    [TR]
    [TD]Manufacturer[/TD]
    [TD]Chemistry[/TD]
    [TD]Size[/TD]
    [TD]mAh[/TD]
    [TD]Max discharge[/TD]
    [TD]Lowest resistance*[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]3500[/TD]
    [TD]20A[/TD]
    [TD]0.21Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]3000[/TD]
    [TD]15A[/TD]
    [TD]0.28Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]ICR/NP[/TD]
    [TD]18650[/TD]
    [TD]3400[/TD]
    [TD]17A[/TD]
    [TD]0.25Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]ICR/NP[/TD]
    [TD]18650[/TD]
    [TD]3100[/TD]
    [TD]6.2A[/TD]
    [TD]0.67Ω
    [/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]3000[/TD]
    [TD]30A[/TD]
    [TD]0.14Ω
    [/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]2600[/TD]
    [TD]5.2A[/TD]
    [TD]0.81Ω
    [/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2500[/TD]
    [TD]35A[/TD]
    [TD]0.12Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR(Hybrid)[/TD]
    [TD]18650[/TD]
    [TD]2250[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR(Hybrid)[/TD]
    [TD]18650[/TD]
    [TD]2200[/TD]
    [TD]17.6A[/TD]
    [TD]0.24Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2100[/TD]
    [TD]30A[/TD]
    [TD]0.14Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2000 (v1)[/TD]
    [TD]10A
    [/TD]
    [TD]0.41Ω
    [/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2000 (v2)[/TD]
    [TD]10A
    [/TD]
    [TD]0.41Ω
    [/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1600[/TD]
    [TD]30A
    [/TD]
    [TD]0.14Ω
    [/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1500[/TD]
    [TD]15A
    [/TD]
    [TD]0.28Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18490[/TD]
    [TD]1100[/TD]
    [TD]8.8A[/TD]
    [TD]0.48Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]ICR/NP[/TD]
    [TD]18350[/TD]
    [TD]900[/TD]
    [TD]9A[/TD]
    [TD]0.47Ω[/TD]
    [/TR]
    [TR]
    [TD]Efest[/TD]
    [TD]IMR[/TD]
    [TD]18350[/TD]
    [TD]800[/TD]
    [TD]6.4A[/TD]
    [TD]0.66Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]2300[/TD]
    [TD]16A[/TD]
    [TD]0.26Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]3400[/TD]
    [TD]6.8A[/TD]
    [TD]0.62Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]3100[/TD]
    [TD]6.2A[/TD]
    [TD]0.67Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]2900[/TD]
    [TD]5.8A
    [/TD]
    [TD]0.72Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]2600[/TD]
    [TD]5.2A[/TD]
    [TD]0.81Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]2200[/TD]
    [TD]4.4A[/TD]
    [TD]0.95Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2000[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1600[/TD]
    [TD]24A[/TD]
    [TD]0.18Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]ICR[/TD]
    [TD]18490[/TD]
    [TD]1500[/TD]
    [TD]3A[/TD]
    [TD]1.4Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]IMR[/TD]
    [TD]18490[/TD]
    [TD]1100[/TD]
    [TD]8.8A[/TD]
    [TD]0.48Ω[/TD]
    [/TR]
    [TR]
    [TD]AW[/TD]
    [TD]IMR[/TD]
    [TD]18350[/TD]
    [TD]700[/TD]
    [TD]6A[/TD]
    [TD]0.7Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]Sony[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]2600[/TD]
    [TD]50A[/TD]
    [TD]0.08Ω[/TD]
    [/TR]
    [TR]
    [TD]Sony[/TD]
    [TD]IMR(Hybrid)[/TD]
    [TD]18650[/TD]
    [TD]2100[/TD]
    [TD]30A[/TD]
    [TD]0.14Ω[/TD]
    [/TR]
    [TR]
    [TD]Sony[/TD]
    [TD]IMR(Hybrid)[/TD]
    [TD]18650[/TD]
    [TD]1600[/TD]
    [TD]30A[/TD]
    [TD]0.14Ω[/TD]
    [/TR]
    [TR]
    [TD]Sony[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1300[/TD]
    [TD]20A[/TD]
    [TD]0.21Ω[/TD]
    [/TR]
    [TR]
    [TD]Sony[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1100[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]Trustfire[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]5000[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD]Trustfire[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]4000[/TD]
    [TD]8A[/TD]
    [TD]0.53Ω[/TD]
    [/TR]
    [TR]
    [TD]Trustfire[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]3000[/TD]
    [TD]4.5A[/TD]
    [TD]0.93Ω[/TD]
    [/TR]
    [TR]
    [TD]Trustfire[/TD]
    [TD]ICR/P[/TD]
    [TD]18650[/TD]
    [TD]2400[/TD]
    [TD]3.6A[/TD]
    [TD]1.17Ω[/TD]
    [/TR]
    [TR]
    [TD]Trustfire[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1500[/TD]
    [TD]7.5A[/TD]
    [TD]0.56Ω[/TD]
    [/TR]
    [TR]
    [TD]Trustfire[/TD]
    [TD]IMR[/TD]
    [TD]18490[/TD]
    [TD]1300[/TD]
    [TD]6.5A[/TD]
    [TD]0.65Ω[/TD]
    [/TR]
    [TR]
    [TD]Trustfire[/TD]
    [TD]IMR[/TD]
    [TD]18350[/TD]
    [TD]800[/TD]
    [TD]4A[/TD]
    [TD]1.05Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]4000[/TD]
    [TD]15A[/TD]
    [TD]0.28Ω[/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2250[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2000[/TD]
    [TD]16A[/TD]
    [TD]0.26Ω[/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]ICR/NP[/TD]
    [TD]18650[/TD]
    [TD]1600[/TD]
    [TD]20A[/TD]
    [TD]0.21Ω[/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1600[/TD]
    [TD]30A[/TD]
    [TD]0.14Ω[/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1500[/TD]
    [TD]22A[/TD]
    [TD]0.19Ω[/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]IMR[/TD]
    [TD]18490[/TD]
    [TD]1100[/TD]
    [TD]8.8[/TD]
    [TD]0.48Ω[/TD]
    [/TR]
    [TR]
    [TD]EH[/TD]
    [TD]IMR[/TD]
    [TD]18350[/TD]
    [TD]800[/TD]
    [TD]6.4[/TD]
    [TD]0.66Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]MNKE[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]3800[/TD]
    [TD]20A[/TD]
    [TD]0.21Ω[/TD]
    [/TR]
    [TR]
    [TD]MNKE[/TD]
    [TD]IMR[/TD]
    [TD]26650[/TD]
    [TD]3500[/TD]
    [TD]15A[/TD]
    [TD]0.28Ω[/TD]
    [/TR]
    [TR]
    [TD]MNKE[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]1500[/TD]
    [TD]20A[/TD]
    [TD]0.21Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]Panasonic[/TD]
    [TD]NCR[/TD]
    [TD]18650[/TD]
    [TD]3400[/TD]
    [TD]4A[/TD]
    [TD]1.05Ω[/TD]
    [/TR]
    [TR]
    [TD]Panasonic[/TD]
    [TD]NCR[/TD]
    [TD]18650[/TD]
    [TD]2900[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD]Panasonic[/TD]
    [TD]IMR[/TD]
    [TD]18650[/TD]
    [TD]2250[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]Orbtronic[/TD]
    [TD]IMR(Hybrid)[/TD]
    [TD]18650[/TD]
    [TD]2100[/TD]
    [TD]30A[/TD]
    [TD]0.14Ω[/TD]
    [/TR]
    [TR]
    [TD]Orbtronic[/TD]
    [TD]IMR(Hybrid)[/TD]
    [TD]18650[/TD]
    [TD]2000[/TD]
    [TD]22A[/TD]
    [TD]0.19Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]Samsung[/TD]
    [TD]ICR[/TD]
    [TD]18650[/TD]
    [TD]3000[/TD]
    [TD]3A[/TD]
    [TD]1.40Ω[/TD]
    [/TR]
    [TR]
    [TD]Samsung[/TD]
    [TD]ICR[/TD]
    [TD]18650[/TD]
    [TD]2200[/TD]
    [TD]10A[/TD]
    [TD]0.42Ω[/TD]
    [/TR]
    [TR]
    [TD]Samsung[/TD]
    [TD]INR[/TD]
    [TD]18650[/TD]
    [TD]2000[/TD]
    [TD]22A[/TD]
    [TD]0.19Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]Sanyo[/TD]
    [TD]¿?[/TD]
    [TD]18650[/TD]
    [TD]2000[/TD]
    [TD]20A[/TD]
    [TD]0.21Ω[/TD]
    [/TR]
    [TR]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [TD][/TD]
    [/TR]
    [TR]
    [TD]Ultrafire[/TD]
    [TD]ICR/NP[/TD]
    [TD]26650[/TD]
    [TD]5000[/TD]
    [TD]8A[/TD]
    [TD]0.52Ω[/TD]
    [/TR]
    [/TABLE]
  2. In order for this to be a comprehensive guide I have decided to go through batteries in detail. It should be noted that there are plenty of great resources on the ECF which pertain to battery safety. Of note are Baditude's blogs.

    Contents:
    1. What do all the numbers and letters mean?
    2. ICR vs IMR
    3. Battery failure
    4. Avoiding battery failure
    5. Long term battery life
    6. Battery charge

    1. What do all the numbers and letters mean?

    In short – The numbers refer to the battery sizes, and the letters refer to the chemistry.

    Size descriptors:
    There are three main sizes of batteries that are used in mods; 18650, 18490 and 18350. The numbers are a reference to the dimensions of the battery. Height, and width.

    The first two numbers are the diameter of the battery in mm, the three subsequent numbers are the height in mm.

    So:
    An 18650 is 18mm in diameter, 650 mm in height.
    An 18490 is 18mm in diameter, 490 mm in height.
    An 18350 is 18mm in diameter, 350 mm in height.

    Chemistry descriptors:
    The two main types of batteries we use are ICR and IMR.

    Each letter in the designation means something different:
    I – Lithium-ion
    C – Cobalt
    M – Manganese
    R – Rechargeable

    C-ratings and mAh:
    The C-rating of a battery refers to how much continuous output the battery can handle, as a function of mAh. mAh refers to how much charge a battery can hold.

    The relationship is:
    Maximum current output in amps = C-rating * mAh / 1000

    So a 1600 mAh battery with a C-rating of 20 can output 20 * 1600 / 1000 = 32 amps.

    2. ICR vs IMR

    ICR batteries are generally cheaper, and have low C-ratings, thus they have low maximum amp draw. The cobalt chemistry that they use is the common chemistry used in lithium ion rechargeable batteries, including those in AA. Due to the relatively volatile chemistry used in cobalt based chemistry batteries, they often come with a PCB (printed circuit board) attached on one end of the battery. It is essentially a fuse for the battery, ensuring that the battery will never output more than it can handle. ICR batteries with a PCB are typically referred to as ‘protected’. It is highly inadvisable to use non protected ICR batteries!

    IMR batteries are more expensive and have high C-ratings, as a result they are considered ‘high drain’, thus they have high maximum amp draw. The manganese chemistry that they use is generally considered much safer than cobalt, as a result they do not come with PCBs, nor require them.

    3. Battery failure

    When the maximum current draw of a battery is exceeded the results can range from a hot battery, to catastrophic pipe bomb style failure. What happens generally depends on how long the battery exceeded its maximum draw, and by how much.

    To keep this relatively simple, we wont go into the way a battery works, ion movement, or any of that scarily complicated chemistry.

    What is important is that once the maximum discharge rate of a battery is exceeded heat will start to build up in the battery. Since the battery is mostly liquid inside this excess of heat can eventually start to boil the liquid. Once the liquid boils it will cause a massive pressure rise in the battery. If the force exerted by this pressure is greater than what the casing can handle, the casing will fail, expelling the contents of the battery. The more the maximum rating of the battery is exceeded, the faster heat will build up and the quicker the battery will fail.

    Lucky for us most batteries casings are slightly flawed, sometimes by design. This results in one part of the casing failing before the rest of it. So for example, the top may pop off, venting in just one direction. In cases where the entire casing can handle the exact same pressure, the whole thing will fail at the same time, like a pipe bomb.

    4. Avoiding battery failure

    Scarily, there are MANY reasons why a battery might fail.

    a. Your build
    If for example you build a 0.1 ohm coil, and use it with a battery whose maximum discharge rate is 10A, your build will try to draw 4.2 / 0.1 = 42 amps from the battery. This FAR exceeds the maximum draw of the battery, and will result in failure quite quickly.

    b. Short circuit due to a bad build
    If you have a short circuit on your build – when a lead is touching the deck, or a post, or wraps are overlapped, etc – the resistance of your coil will drop. How much it drops by depends on just what kind of short circuit you have. If the resistance drops to the point that the maximum amp draw is exceeded – battery failure.

    c. Short circuit for other reasons
    A great (or terrifying) example of this happened to a friend of mine. He simply tossed a battery into his inside coat pocket… with his keys. The keys connected the poles of the battery, creating a short circuit. He was lucky enough to feel the heat before anything catastrophic happened, he did the smart-ish thing and threw the battery in a snow bank. This was smart because it cooled down the battery rather quickly. Dumb because he handled the battery with his hands, and also because the lithium in the battery, if it vented, would react with the water in the snow bank.

    Protip – Always store your batteries in a battery case!

    5. Long term battery life

    Over time batteries do degrade. This is because during the recharge process lithium is deposited in small quantities on the electrodes in the battery. Over time this can result in shorts or corrosion.

    How many cycles you can put your battery through depends on many factors. But as a rule of thumb do not keep them for more than a year.

    Factors that can reduce the life of your battery:
    a. Extreme hot cold temperature changes
    Avoid leaving your batteries in an overly hot or cold car. Keep them away from your heaters. This one is pretty self explanatory.

    b. Over charging
    Just like not all batteries are created equal, not all chargers are created equal. The best charger on the market at the moment is the Nitecore intellicharger.

    c. Over discharging
    Most batteries will simply stop firing when they reach a certain voltage (normally 2.7). This is not always the case though, discharging past this can also cause issues.

    d. Too frequent charging
    Every charge cycle your battery goes through can result in lithium being deposited. So, the more frequently you charge a battery, the less life you can expect from it.

    The result of this, to maximise your battery life, is a rather delicate balancing act. You dont want to overcharge, nor overdischarge, nor charge too frequently. So you want to make sure that your charger does not exceed 4.2 volts, you also want to make sure you do not discharge past 2.7 volts. A good charger, like the nitecore, can read the voltage on your battery, helping you avoid this.

    6. Battery charge

    It is relatively easy to calculate how long your battery will last based on the mAh rating of your battery.

    mAh is the unit for milliamp-hour This means the number refers to how many milliamps the battery can discharge at in order to discharge for a full hour.

    So for example, a 3000 mAh battery can discharge at 3000 milliamps (3 amps) for one hour.

    If you discharge at a higher rate than this, the math is simple to calculate how many seconds you can expect to get out of your battery with your current build:

    seconds = (mAh rating / 1000) / (amps your drawing) * 3600

    So for example, if you were to draw 9 amps continuously from a battery rated at 3000 mAh (which better be able to handle 9 amps!) you can expect:

    (3000 / 1000) / 9 * 3600 = 1200 seconds = 20 minutes


    I hope this all made sense, if you have any comments or questions feel free to leave them in the comment section and either I or some other knowledgeable person will surely answer you!

    Happy vaping!
  3. Welcome to part 2 of electrical theory!

    It is imperative that somebody intending to move into the world of sub ohm cloud chasing understand how to calculate what is going to happen in their build. Without understanding how to do this, you have no backbone to understanding what is going on in your device when you fire it, and thus cannot safely do so.

    I recommend reading and understanding the first post of my blog in order to fully understand what is to follow in this post. While not required, it will give you a greater understanding of the concepts involved when building coils.

    Disclaimer: This is meant as a guide to help those who are determined to get into the world of sub ohm vaping. You do so at your own risk. While I will go over as many important details as I can in this guide there can always be unforeseen events that can cause problems. NO BUILD IS FAIL PROOF. I accept no responsibility for any damage done to your devices, or yourself as a result of following this guide.

    Also, I will to an extent I will oversimplify some concepts. To avoid the vehemence of fellow physicists, I will simply state now that this guide is meant for novices to electrical concepts. This means that some things I say here are not completely true, though I will endeavor to keep things as close to the absolute truth as possible. If I was to try to give a completely true account of this theory, it would involve degree level knowledge of quantum mechanics.

    Contents:
    1.1 The transfer of electrical energy to heat energy
    1.2 Ohms Law
    1.3 Power

    1.1 The transfer of electrical energy to heat energy

    As electrons flow through a wire they flow with more or less a fixed speed. As an electron encounters resistance, in the form of the atoms arranged in the wire, the electrons must give up some energy in order to get past this resistance.

    An analogy for this is to imagine a car driving down a road. On nice clean tarmac a car uses comparatively little energy to drive down the road. If you now cover the road in water (which resists the cars passage) the car must now use more energy to drive down the road at the same speed. If you cover the road in mud, it must use even more energy to drive at the same speed. An electron is similar to a car in this way, some arrangements of atoms are harder for the electron to pass, the electron must thus give up more energy in order to get through.

    In both cases, the electron and the car, energy is always conserved. This means that it doesn’t just disappear, it has to go somewhere. In the case of the electron the extra energy used is passed on to the atoms it is getting past. This extra energy results in the atoms vibrating more. The faster an atom vibrates, the higher its temperature.

    So to summarize, when an electron loses energy by passing a resistance, the energy is absorbed by the atoms, resulting in a higher temperature.

    Now, what is going to result in more heat transfer? More voltage, or more amperage?

    To answer this question, we can think of the atom arrangements in the wire as a series of energy toll booths. At each toll booth along the road, the electron must pay some energy in order to get past. This happens regardless of how much energy the electron has (voltage). So, lets use some completely crazy numbers to explain this.

    Imagine a wire with five energy toll booths, each toll booth has an energy fee of one joule. One electron with ten joules of energy passes through this series of toll booths. At the end of its passage it will have ‘paid’ five joules of energy. Now imagine five electrons passing through the same series of toll booths, each electron will have to ‘pay’ five joules to get through. So five electrons, each paying five joules, will result in a total payment of twenty five joules of energy.

    Thus, amperage (the number of electrons passing per second) is far more important than the voltage (the amount of energy each electron has) with regards to how much energy is transferred to a coil.

    So why do we adjust voltage on VV devices, and get a different vape experience? This is due to Ohms law.

    1.2 Ohms Law

    Ohms law implies that there is an inescapable, universal relationship between current, voltage and resistance.

    Unfortunately the reason for this law is quantum mechanical and is thus very complicated, so for the purposes of this guide it would be impractical to try and explain it.

    The law can be expressed in various, equally valid mathematical statements:
    Voltage = Amperage * Resistance or V = I*R
    Amperage = Voltage / Resistance or I = V/R
    Resistance = Voltage / Amperage or R = V/I

    The ‘official’ (if there even is one) statement of ohms law is that the current through a conductor is directly proportional to the voltage across the conductor, where the constant of proportionality between the two is the resistance.

    This has a couple of implications that are important to vapers:

    1. With a constant resistance, if you increase the voltage across your coil, the amperage will also increase.
    2. If you maintain a constant voltage, and use a lower resistance coil, the amperage will increase.

    Usually when this law is used by vapers, it is used to calculate amperage, in order to ensure that the build used is safe for the battery.

    To give some examples:
    a) Your battery is rated at 10 amps max output and you build a 1.2 ohm coil. On a full charge most batteries output 4.2 volts.

    Amperage = Voltage / Resistance
    Amperage = 4.2 volts / 1.2 ohms
    Amperage = 3.5 amps
    Since the 3.5 amps required by the build is far less than the 10 amp maximum of the battery, this would be a safe build to use.

    b) Now say you again have a battery rated at 10 amps max output, but this time you build a 0.4 ohm coil.

    Amperage = Voltage / Resistance
    Amperage = 4.2 volts / 0.4 ohms
    Amperage = 10.5 amps
    Now the build will draw 10.5 amps and the battery is only rated for 10 amps, this would be a dangerous build.

    More on battery safety and outputs will follow in another post.

    There are various ohms law calculators you can use if you are scared of messing up the maths. On both android and apple devices you can simply search ohms law calculator on the app store.
    On a pc you can use Ohm's Law Calculator
    On most of these apps you could just plug in the voltage (almost always 4.2 on a mechanical mod) and the resistance of your coil. Hit the calculate button and the results will pop up.

    1.3 Power
    Power, measured in watts, is a description of how much energy a particular flow of electrons can deliver every second. It is a unit that is derived from the units of voltage and amperage.

    Voltage is the amount of energy per coulomb of electrons. Amperage is how many electrons flow per second.

    Mathematically the relationship is described as:

    Power = Amperage * Voltage or P = I * V

    In terms of units:
    Energy / Time = Coulomb / Time * Energy / Time

    Examples:
    a) A coil draws 2 amps from a mech mod battery (4.2 volts max).
    I * V = P
    2 amps * 4.2 volts = 8.4 watts at a full battery charge

    b) A coil draws 4 amps from a variable voltage device set at 3.8 volts
    I * V = P
    4 amps * 3.8 volts = 15.2 watts

    The above formula can be substituted into ohms law to yield two further useful formulas:
    Power = Voltage[SUP]2 [/SUP]/ Resistance or P = V[SUP]2[/SUP] / R
    Power = Amperage[SUP]2[/SUP] * Resistance or P = I[SUP]2[/SUP] * R

    The most commonly used power formula for vapers is the one relating power, voltage and resistance. This is because it is very easy to tell what voltage a battery is supplying.

    Examples:
    a) A battery in a mech mod (4.2 volts max) is connected to a 0.8 ohm coil.
    P = V[SUP]2[/SUP] / R
    P = 4.2[SUP]2[/SUP] / 0.8
    P = 22.05 watts

    b) A variable voltage device is set to 3.6 volts and is connected to a 1.2 ohm coil.
    P = V[SUP]2[/SUP] / R
    P = 3.6[SUP]2[/SUP] / 1.2
    P = 10.80 watts

    The only use I can really think of for a power value with respect to mechanical mods is if you want to emulate the result you get from a variable wattage mod.

    Lets say that you have a specific wattage that you like to vape your favorite juice at on your VW mod. In order to emulate that experience, your going to need to tinker with your mechanical mod in order to get the same result. Of course, the only value you can tinker with is the resistance of the coil, and the only value you know (besides the power you want) is the voltage of the battery. So we rearrange the formula:
    P = V[SUP]2[/SUP] / R changes to R = V[SUP]2[/SUP] / P
    In this way, we can calculate the resistance of the coil you will need on your mechanical mod in order to achieve the desired power.

    Example:
    You like to vape your favorite juice at 10 watts on your VW. You want to do the same on your mechanical. The median voltage of a battery is 3.7 volts, the maximum is 4.2 volts. Over the life of the battery charge the voltage will drop over time, however for the most time it will be around 3.7.

    R = V[SUP]2[/SUP] / P
    R = 3.7[SUP]2[/SUP] / 10
    R = 1.37 ohms

    So to get the same 10 watt experience on your mechanical mod your going to need to build a 1.37 ohm coil for it. Keep in mind though that when fully charged the battery will deliver 4.2 volts, so at first your going to be vaping at:

    P = V[SUP]2[/SUP] / R
    P = 4.2[SUP]2[/SUP] / 1.37
    P = 9.40 watts

    And this ends the theory portion of this guide. If you do not understand how to calculate amps, DO NOT MOVE ON TO RDAs! In a subsequent post I will go over why this is SO important.

    I hope this all made sense, if you have any questions please feel free to leave a question and either myself or another knowledgeable person will be sure to respond.

    Happy vaping!
  4. Welcome to my blog!

    This guide is intended for folks who are new to vaping and want to dive into the deep end. It has been brought up many times on the ECF that people who are inexperienced are trying to dive into cloud chasing without knowing the basics. Unfortunately, I dont think this can be avoided, people will do as people do, the only way to ensure somebody's safety is to educate, rather than rant. With this in mind I have devised a series of blog posts with the intention of providing the reader with the knowledge they require to get into RDAs and cloud chasing.

    In the first post of this guide I will be going through the terms used when describing electrical theory. This part of the guide is not required for going into sub ohm vaping, but it is well recommended that you understand them. The greater your understanding of electrical theory, the safer you will be when building sub ohm.

    Disclaimer: This is meant as a guide to help those who are determined to get into the world of sub ohm vaping. You do so at your own risk. While I will go over as many important details as I can in this guide there can always be unforeseen events that can cause problems. NO BUILD IS FAIL PROOF. I accept no responsibility for any damage done to your devices, or yourself as a result of following this guide.

    Also, I will to an extent I will oversimplify some concepts. To avoid the vehemence of fellow physicists, I will simply state now that this guide is meant for novices to electrical concepts. This means that some things I say here are not completely true, though I will endeavor to keep things as close to the absolute truth as possible. If I was to try to give a completely true account of this theory, it would involve degree level knowledge of quantum mechanics.

    Contents:
    1.0 Defining and Explaining Terms
    1.1 Coulomb
    1.2 Voltage
    1.3 Amperage
    1.4 Resistance

    1.0 Defining and Explaining Terms
    For the purposes of this guide we will view electricity as a flow of electrons through a wire. While this is not entirely accurate, it is unnecessary to view it as anything other to explain these concepts.

    1.1 Coulomb (C)
    When describing electrical concepts such as voltage and amperage, we are describing attributes of the particular flow of electrons in the coil. Electrons are very small and very numerous, if we tried to talk about everything in terms of exact numbers of electrons, the numbers would get huge and thus unintelligible very quickly. Thus the coulomb, it is a constant, a set number of electrons. To be exact, 1 coulomb is equal to 6.241 x 10[SUP]18[/SUP] electrons.

    1.2 Voltage – Volts (V)
    Voltage, measured in volts, is a description of the amount of energy one coulomb of electrons can transfer. It comes in many forms, sometimes called potential difference, sometimes described as electromotive force, for our purposes we will simply refer to it as voltage.

    The more voltage a packet of electrons contains, the more oomph it has, the more energy it can deliver, the more of a zap you would get if subjected to it.

    1.3 Amperage – Amps (I)
    Amperage (aka current), measured in amps, is a description of the number of coulombs of electrons pass through a point in one second.

    Therefore, the more amps a device is outputting, the more electrons it is putting out per second. This is why many batteries have amp ratings, some can only put out so many electrons per second, depending on their chemistry.

    1.4 Resistance – Ohms (R)
    Resistance is a strange concept. The fire hose is a common, and very useful way to understand it, I won’t break with tradition.

    Imagine a fire hose and garden hose. Water flows through the hoses just as electrons ‘flow’ through a wire. The thinner the hose, the harder it is for water to flow through the hose. The thicker the hose, the easier it is for water to flow. The hose is a resistor to water flow, just as a wire is a resistor to electron flow.

    There are quite a few factors that influence the resistance of a wire:


    1. Thickness – This is well described by the fire hose example. The thinner the wire, the less room there is for electrons to manoeuvre. The thicker the wire, the more room, thus, with a thicker wire more electrons can flow at the same time.
    2. Length – The longer a wire is, the more resistance the electrons will encounter along their path. This is why most resistance wires are rated with a resistance per inch value.
    3. Material – Different wires types are made out of different materials. Different materials have different chemical compositions and as a result, the atoms are arranged differently. This different arrangement makes some wires harder for electrons to pass through them, while in others it makes it easier.
    4. Temperature – The more the atoms in a material vibrate, the harder it is for electrons to pass through the material. As a result of this the higher the temperature of a coil, the higher the resistance. Due to the very rapid transfer of heat from coil to juice however, the temperature of coils remain more or less constant, and thus, temperature is not so great of a factor. It is for this reason however, that it is important when dry burning a coil to pulse the battery rather than supply a continuous current.