This will blow up if the calculations are correct!

[Curly Howard]

I would first like to introduce myself to the forum... Hello everyone! good, now that is out of the way -
I have been vaping for a little over 3 years, I started getting lazy and bored with building/wicking coils. I started noticing email adds about fancy sub ohm tanks with replaceable coils. i started off with the smok v4 and went from there. today i got a TFV12 cloud beast king in the mail as the cost of 3 coils on my v8 mini beast were near the cost of a new atomizer that came with 3 coils.
I filled and primed the tank with the coil already installed which was the V12-T12 0.12ohm (duodenary?) coil and plopped it on the top of my Smok Alien 220W dual 18650 regulated mod. and went to town starting at 60w.
I looked at the screen and saw that the amperage was somewhere in the ballpark of 24 amps
my sony vtc5's are only rated for a maximum (according to the manufacturer) of 20A.

The coil itself is rated from 60w-350w with the "best" range between 130w-200w but using ohm's law and a hypothetical assumption that my mod is 100% efficient... my vtc5's can only run at 48w @2.4v

what I want to know is how can anyone run this atomizer safely with anything less than a hex-18650 series/parallel setup(3 parallel sets of 2 batteries in series)?
as far as I can find on the internet no major battery manufacturers sell 18650's with a safe discharge over 25 amps.
there are a few I found that claim 40A and 3000mah which should not exist. it is either large capacity and low discharge rate or high discharge and low capacity; not both. so I'm assuming they are in the same category as snake oil.

@220Watts which is the maximum my 2 battery mod can push, the amperage on the .12ohm coil should be running @42.8Amps which is more than twice the rated output of my batteries and most batteries on the market.

the peak wattage of the atomizer is 350 watts, so for grins that would be 54Amps @6.48Volts which would almost triple the maximum amperage of my batteries.

If you use this atomizer, which batteries/mod do you use and what wattage do you run them at?
I also understand that you can go over your rated amperage and it won't explode MOST of the time and you would have to carry around a mod half the size of a car battery to run this thing properly.
Please give me your thoughts and I apologize if I posted this in the wrong section.

 

[Curly Howard]

i just saw that i posted this in the ejuice thread . how do i move it?

 

[Izan]

Hi,
Disregard the Smok propaganda.

Safe power delivery will be limited by the cells you choose.

Cheers
I

 

[Curly Howard]

thank you for your reply, but after some time on google translate... it is saying that these are safe wattages for said batteries and some other general safety stuff. that may be true as a guideline but for the sony vtc5 it says 120 watts is safe with two batteries. you can have a setup where it safely runs at 120 watts UNDER 20 amps. for example: if you have a .3 ohm coil @6v you are running 120 watts at 20Amps.

but if you lower the resistance to say .12 Ohms like the coil that comes IN the smok TFV12 and run it at 120 watts, you are more than 50% over the rated amperage of the battery at 31.3625 amps

so charts like that scare me because people can hurt themselves because it is simply wrong information. it is very polished and official looking though.

 

[Hawise]

Hi Curly Howard, welcome to the forum.

Your calculations aren't working because you're using formulas for mech (mechanical) mods, not regulated mods. Here's how to calculate your battery draw for a regulated mod:

Calculating battery current draw for a regulated mod | E-Cigarette Forum

Ohm's law isn't used to calculate draw from a regulated mod because you're not drawing directly from the battery(ies). There's a chip in the mod that pulls extra power to increase the voltage or less power when the native voltage is higher than you need. That means that you'll be pulling the most power when the batteries are nearly discharged, which, for most mods, means about 3.2 V.

Resistance isn't a factor for regulated mods. The batteries only see the chip, not the coil.

You have two batteries, not one. For regulated mods, it doesn't matter if they're parallel or in series.

Chips aren't entirely efficient, so a 90% efficiency factor is also added.

This gives you the calculation in the link:

Amps per battery = Wattage per battery/volts per battery/0.9

Your watts per battery at 120W is 120/2 = 60. Volts, as I mentioned above, are 3.2. So:

Amps per battery = 60/3.2/0.9 = 20.8. The VTC5 is a 20 A battery, so that's about right (and about the limit - you wouldn't want to take it higher).

 

[doctadrea]

Thanks for that info about regulated vs mech. I've always sort of wondered but not enough to go looking for the info, since I mostly use mechs and don't vape very high wattage anyway (I have one very airy atty built to .37, but my sweet spot for most is around .45).

 

[Curly Howard]

Thank you all for the replies, it is very comforting to know that i was wrong in my calculations! may may faces be saved from lithium burns!!!!! i stayed up until 4 in the morning googling this subject and i did eventually find some seemingly reliable 30A batteries with testing to support them, and my only remaining question is with a 30A battery that still doesn't get you anywhere near the 150W-220W or 350watts. I just don't want anyone to get hurt while vaping because every time it happens it makes us ALL look bad on the news. you never hear an article saying...millions of people vaped safely today, most of them were able to quit cigarettes and nothing bad happened. The media likes to make an example of everyone who had a short and blew their mod (mech or reguated) or did something unsafe. I did forget to account that the battery voltage is being stepped down by the chip and therefore reducing the amperage flow out of the battery. i don't understand why the formula works just yet. my memory has been foggy because it has been over 12 years since i have taken my last electronics course and have been working on refrigeration systems ever since. this is one case where i'm glad that i'm wrong.

 

[Hawise]

my only remaining question is with a 30A battery that still doesn't get you anywhere near the 150W-220W or 350watts. I just don't want anyone to get hurt while vaping because every time it happens it makes us ALL look bad on the news. you never hear an article saying...millions of people vaped safely today, most of them were able to quit cigarettes and nothing bad happened. The media likes to make an example of everyone who had a short and blew their mod (mech or reguated) or did something unsafe.

Absolutely correct. Actually, two 30A batteries will get you to 150W, but not to 220W. There are three and four battery mods that will go higher, but again not to the limits of the mod. The problem is that mods give their wattage based on what the board can handle even though there aren't any batteries that can safely provide enough power to reach that wattage. Add in the fact that a lot of people a) don't check the batteries' specs or b) do, but then buy rewraps that don't have accurate specs, and you have a recipe for disaster. And that doesn't even take into account the prevalence of counterfeits.

Have you checked out Mooch's blog yet? He's our resident battery guru and has run a lot of tests on vaping batteries. His list of recommended batteries and reliable battery suppliers is here:

Mooch's Recommended Batteries | E-Cigarette Forum

His blog is an interesting and useful read.