Shaun’s Guide to Battery Safety
There is an incredible amount of information available for those who intend to vape at sub ohm resistances. However, there seems to be a lot of misconceptions going around about how to sub ohm safely due to some gaps in our knowledge. As a fellow sub ohm vaper I wanted to clarify a few things that seem to be frequently misunderstood about how to vape safely.
This post is geared toward those who already understand the basics of sub ohm vaping.
Minimum safe resistance
It seems to be very common for people to seek out batteries specifically for their high current ratings.
However, for the majority of sub ohm vapers, this high of an amp rating is unnecessary, and can even be misleading. In fact, there is a very narrow window between vaping at 20 amps (A) and vaping at 30A, and unless your coil build happens to fall within this tiny window, 30A batteries aren’t going to be much more useful to you.
Let me illustrate my point. We are all familiar with Ohm’s law: voltage equals current times resistance, or V = I*R. With a little algebra we can find out what resistance we have at a certain voltage and current, R = V/I. Using this equation we can find the minimum resistance we can build to given the current rating of the battery.
For all 18650 and 26650 batteries, the maximum voltage when charged is 4.2 volts (V). Plugging this into the equation along with the max continuous current rating of the battery will give you the absolute minimum resistance you can build to without overstressing your battery.
For a battery rated at 20A continuous, we have R = 4.2V / 20A = 0.21 ohms (Ω).
At 30A, we have R = 4.2V / 30A = 0.14Ω.
*bottom line is there is a point where your build resistance needs to stop before you create a risk on your batteries even though your mod will still fire them.
Amp ratings – continuous versus pulse
Many people say that they can build to very low resistances because they go by the battery’s pulse rating rather than the continuous rating. It is rumoured that batteries can handle a much higher current output because of the pulse rating.
this is false.
Continuous amp ratings are the maximum current that the battery can handle discharging over a very long period of time. Pulse ratings, on the other hand, are the maximum amount of current the battery can discharge in a very short period of time.
The problem with pulse ratings is that there is no universally accepted standard for battery companies to test pulse ratings. A pulse is simply defined as a discharge in a brief time window, but there is no way to know exactly how long that pulse lasted in testing. A pulse time can be anywhere from a couple seconds all the way down to a fraction of a second – in theoretical mathematics, the time of a pulse is considered “infinitely” short.
How long do you hold the button down when vaping? Try timing it – I’m willing to bet it’s somewhere between 2 and 10 seconds. Did the battery factory time their pulse testing to accommodate that? Probably not.
Since we have no way of knowing how pulse ratings are determined, it’s safe to assume they don’t apply to vaping. It’s better to stick to the continuous amp rating.
Batteries in pairs
There are now many mods available that accommodate two, or more, batteries at once. There is a significant difference in performance capabilities between whether they are connected in series or parallel.
It is important that you always buy the pair of batteries used in the mod together, and always use them together and charge them together. Any difference between them can lead to one battery pumping out more voltage than the other and becoming strained. This is often referred to as “married batteries”
Batteries connected in series will retain the same current but double the voltage. For instance, if you use two 20A batteries, you will still have a max current discharge of 20A, but you will have a max voltage output of 8.4V. This is helpful if your goal is to maximize power, or wattage (W), without decreasing the resistance of your build.
In fact, this will increase your power by a lot. Power is equal to the voltage times the current, or P = V*I. If you use 20A batteries and build to the lowest resistance possible, your power from one battery at max voltage is 4.2V * 20A = 84W. If you stack two of these batteries, however, your power is now 8.4V * 20A = 168W!
Many people who stack batteries find that they prefer building their coils to a higher resistance because of this.
Batteries wired in parallel will retain the voltage but double the current. So now if you use two 20A batteries, you will retain a voltage of 4.2 but have a max continuous current of 40A. This allows you to lower the resistance of your build.
If you pair two 20A batteries, your minimum resistance is now 4.2V / 40A = 0.11Ω. If you pair two 30A batteries, your minimum resistance becomes 4.2V / 60A = 0.07Ω!
That’s about as low as it gets. If you plan to build to extremely low resistances, I highly recommend buying a box mod that runs batteries in parallel.
Regulated Mods Internal Safety Mechanism
A lot of people would say they don’t worry about what they build because their mod will protect them. It will give you an error when you going wrong. I fully agree that this will happen for errors like short-circuits, reversed polarity, and when exceeding the chipsets lowest resistance.
But not all mods are created equally and I have seen me far share of mods DIE a slow and painful dealt because of incorrect batteries and unsafe builds.
My intern is a very dumb person. He got himself an IPV3 li and then instead of buying a pair of decent batteries he went to the china mall and got himself a pair of ultrafire 18650’s because it’s the same thing as his father’s torch and only cost R20.00 each! He then built a Clapton build and pushed his to 100W. After a few min he started to feel his mod vibrate in his hand, smoke started to pour out of the batteries as it leaked and then bang! His mod had melted.
My personal legendary sigelei 150w however had a different story. I had built a super sub ohm coil. 0.12 ohm resistance and was firing it at 150w. Once the battery got to 80% it refused to fire and had the check battery message. So I took the batteries out and placed them into the snowwolf with the same atty and it fired. So I kept vaping for another 5min and then the front panel of the snowwolf started to get very hot especially where the buttons were. There was a feeling of a relay clicking inside the mod each time I fired it and I then decided to stop playing around and packed it all away.
There was something in the chipset of the segelei that refused to fire the mod when the batteries got too low to power that coil but not in the snowwolf.
The most important thing is to check what mod you have, then consider what batteries your using and look at the ohms law chart and see what’s your lowest available resistance. I very often choose to build lower than what is recommended for me and push higher power than I should but I do it with full knowledge of the risks and have only myself to blame if something goes wrong.
There is an incredible amount of information available for those who intend to vape at sub ohm resistances. However, there seems to be a lot of misconceptions going around about how to sub ohm safely due to some gaps in our knowledge. As a fellow sub ohm vaper I wanted to clarify a few things that seem to be frequently misunderstood about how to vape safely.
This post is geared toward those who already understand the basics of sub ohm vaping.
Minimum safe resistance
It seems to be very common for people to seek out batteries specifically for their high current ratings.
However, for the majority of sub ohm vapers, this high of an amp rating is unnecessary, and can even be misleading. In fact, there is a very narrow window between vaping at 20 amps (A) and vaping at 30A, and unless your coil build happens to fall within this tiny window, 30A batteries aren’t going to be much more useful to you.
Let me illustrate my point. We are all familiar with Ohm’s law: voltage equals current times resistance, or V = I*R. With a little algebra we can find out what resistance we have at a certain voltage and current, R = V/I. Using this equation we can find the minimum resistance we can build to given the current rating of the battery.
For all 18650 and 26650 batteries, the maximum voltage when charged is 4.2 volts (V). Plugging this into the equation along with the max continuous current rating of the battery will give you the absolute minimum resistance you can build to without overstressing your battery.
For a battery rated at 20A continuous, we have R = 4.2V / 20A = 0.21 ohms (Ω).
At 30A, we have R = 4.2V / 30A = 0.14Ω.
*bottom line is there is a point where your build resistance needs to stop before you create a risk on your batteries even though your mod will still fire them.
Amp ratings – continuous versus pulse
Many people say that they can build to very low resistances because they go by the battery’s pulse rating rather than the continuous rating. It is rumoured that batteries can handle a much higher current output because of the pulse rating.
this is false.
Continuous amp ratings are the maximum current that the battery can handle discharging over a very long period of time. Pulse ratings, on the other hand, are the maximum amount of current the battery can discharge in a very short period of time.
The problem with pulse ratings is that there is no universally accepted standard for battery companies to test pulse ratings. A pulse is simply defined as a discharge in a brief time window, but there is no way to know exactly how long that pulse lasted in testing. A pulse time can be anywhere from a couple seconds all the way down to a fraction of a second – in theoretical mathematics, the time of a pulse is considered “infinitely” short.
How long do you hold the button down when vaping? Try timing it – I’m willing to bet it’s somewhere between 2 and 10 seconds. Did the battery factory time their pulse testing to accommodate that? Probably not.
Since we have no way of knowing how pulse ratings are determined, it’s safe to assume they don’t apply to vaping. It’s better to stick to the continuous amp rating.
Batteries in pairs
There are now many mods available that accommodate two, or more, batteries at once. There is a significant difference in performance capabilities between whether they are connected in series or parallel.
It is important that you always buy the pair of batteries used in the mod together, and always use them together and charge them together. Any difference between them can lead to one battery pumping out more voltage than the other and becoming strained. This is often referred to as “married batteries”
Batteries connected in series will retain the same current but double the voltage. For instance, if you use two 20A batteries, you will still have a max current discharge of 20A, but you will have a max voltage output of 8.4V. This is helpful if your goal is to maximize power, or wattage (W), without decreasing the resistance of your build.
In fact, this will increase your power by a lot. Power is equal to the voltage times the current, or P = V*I. If you use 20A batteries and build to the lowest resistance possible, your power from one battery at max voltage is 4.2V * 20A = 84W. If you stack two of these batteries, however, your power is now 8.4V * 20A = 168W!
Many people who stack batteries find that they prefer building their coils to a higher resistance because of this.
Batteries wired in parallel will retain the voltage but double the current. So now if you use two 20A batteries, you will retain a voltage of 4.2 but have a max continuous current of 40A. This allows you to lower the resistance of your build.
If you pair two 20A batteries, your minimum resistance is now 4.2V / 40A = 0.11Ω. If you pair two 30A batteries, your minimum resistance becomes 4.2V / 60A = 0.07Ω!
That’s about as low as it gets. If you plan to build to extremely low resistances, I highly recommend buying a box mod that runs batteries in parallel.
Regulated Mods Internal Safety Mechanism
A lot of people would say they don’t worry about what they build because their mod will protect them. It will give you an error when you going wrong. I fully agree that this will happen for errors like short-circuits, reversed polarity, and when exceeding the chipsets lowest resistance.
But not all mods are created equally and I have seen me far share of mods DIE a slow and painful dealt because of incorrect batteries and unsafe builds.
My intern is a very dumb person. He got himself an IPV3 li and then instead of buying a pair of decent batteries he went to the china mall and got himself a pair of ultrafire 18650’s because it’s the same thing as his father’s torch and only cost R20.00 each! He then built a Clapton build and pushed his to 100W. After a few min he started to feel his mod vibrate in his hand, smoke started to pour out of the batteries as it leaked and then bang! His mod had melted.
My personal legendary sigelei 150w however had a different story. I had built a super sub ohm coil. 0.12 ohm resistance and was firing it at 150w. Once the battery got to 80% it refused to fire and had the check battery message. So I took the batteries out and placed them into the snowwolf with the same atty and it fired. So I kept vaping for another 5min and then the front panel of the snowwolf started to get very hot especially where the buttons were. There was a feeling of a relay clicking inside the mod each time I fired it and I then decided to stop playing around and packed it all away.
There was something in the chipset of the segelei that refused to fire the mod when the batteries got too low to power that coil but not in the snowwolf.
The most important thing is to check what mod you have, then consider what batteries your using and look at the ohms law chart and see what’s your lowest available resistance. I very often choose to build lower than what is recommended for me and push higher power than I should but I do it with full knowledge of the risks and have only myself to blame if something goes wrong.
