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**Sub-Ohm Vaping** Discussion, Battery, Battery Info, & Warnings

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by , 10-04-2013 at 08:45 PM (741 Views)
Quote Originally Posted by Technonut View Post
Special props to sonicdsl for the idea of making this important sticky happen..

Here's some basic info to get things started:

Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance,[1] one arrives at the usual mathematical equation that describes this relationship:[2]

where I is the current through the conductor in units of amperes, V is the potential difference measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of the current.[3]
Ohm's Law and Vaping

Ohm's Law Calculator

Kanthal A-1 Wire Specs: (Ohms Per Inch)

28 AWG- 0.439 Ohms/in, 0.0508 Diameter (in.)

30 AWG- 0.696 Ohms/in, 0.0100 Diameter (in.)

32 AWG- 1.091 Ohms/in, 0.0080 Diameter (in.)

33 AWG- 1.383 Ohms/in, 0.0071 Diameter (in.)

34 AWG- 1.758 Ohms/in, 0.0063 Diameter (in.)

Sub-Ohm Vaping Vids:

Resistance & Air Flow - YouTube

Batteries, Volts, Amps and You - YouTube

General Battery Info:

Basic to Advanced Battery Information from Battery University

Basics About Battery Discharging

Batteries and Chargers | BudgetLightForum.com

VapeSafe 2 Safety Fuse For Mechanical Mods

Battery C Rating - The C rating of a battery (or cell) is used to indicate the continuous current draw (amps) the cell will support. By multiplying the C rating times the cell capacity in milliamperehours (mAh), the continuous current in milliamperes (mA) of a cell is easily calculated. Example - For a 2000 mAh battery with a 15C rating, the continuous current that may be drawn out of the battery is 2000 mAh x 15 = 30000 mA, or 30 Amps (A) (divide by 1000). There is also another rating that is applicable to a battery known as peak or "burst" current discharge rating. Peak current is higher than continuous C rating. It indicates that a battery will deliver higher current than the C rating for brief instances.
Torchy the Battery Boy: IMR "safe chemistry" batteries

The above is a handy link to popular IMR batteries of all sizes used for vaping, tested at constant 1A, 5A and 10A discharge rates. There are also specs which include:

Internal Resistance mΩ
Actual Capacity(mAh)
Length (mm)
Diamater (mm)
Weight (g)

A Couple Of Trusted Battery & Charger Vendors:

Welcome to RTD Vapor

Batteries-Chargers-Flashlights-Only The Best

Quote Originally Posted by Technonut View Post
I saw this on Reddit... Props to SteamMonkey for writing this:

So... I get the vapor envy... I see those enormous clouds of vapor being spit out and think it's pretty cool myself. But here's the thing... those guys probably know what they're doing.

In the video currently getting bumped around on this sub there is one point where I feel like the guy's being responsible. He says "I need to change the battery, I've been vaping on this one for a couple hours"... that was an AW IMR, a battery most people talk about using 'all day'. He swapped it out for a panasonic CGR18650CH unless my eyes aren't working... batteries that are suited to what he's pulling on that mechanical mod.

Do you know why they're suited? Do you know why he's swapping after just a couple of hours? Now... Do you know how many coils he had or how big his air holes were or what device he was using? If you can't answer with 100% certainty the first two questions but CAN answer the last few... you're the person this is for.

Running an 'extreme' vapor set up for the purposes of generating enormous clouds of vapor is risky. You're pushing batteries to or beyond their operational capacity when you throw low ohm, dual coil set ups on a mech.

The mechanical mod was a great idea at first... people were upset by the fact that their egos kept burning up because of the crappy wires and boards in them so they bypassed the limiting factor, those crappy wires and boards. Every chain has a weak link. If you over work an ego the board burns out or the wires fry. The battery doesn't fail... it's not the weak link.

In a mechanical mod with a solid metal piston for a switch and 0 wires, your weak link is the battery... this is not a link you want to break while it's in close proximity to your face or anything you value more than those clouds of vapor which will dissipate a little faster than your checking account if you over tax a battery and create a little time bomb.

(*)Yes, to the people who will say "it's not that easy to burn out an IMR!" you're right, under normal circumstances it's not. But these batteries are NOT intended for what we're using them for. In fact, after recent conversations with Panasonic/Sanyo, Sony, and Samsung, they don't even like the fact that we're USING these batteries because they're not intended for single cell, unprotected use in any device. The fact that they're available can be attributed to modders of flashlights, pen lasers and bicycle electronics. A demand formed around those markets and it was filled by various folks, ecigs came along and the demand skyrocketed.

These batteries are not built for what we're doing to them. I'm not telling you NOT to do it... don't get me wrong, I plan on making a few little fog machines myself. However, I know my batteries, I know what I'm doing, how I'm doing it, and what the implications are and how to mitigate risks. If you don't... ask, learn, figure it out and don't just take some random Youtube video, drill out your RBA caps and start blowing clouds.

I'll give you a couple of tips but it's by no means all the info you need to have in your brain to push these set ups to the limit so please... it's better to learn before you do something to avoid a bad situation than to jump in, have a bad situation then try to figure out why later.

1. Only use IMR batteries and only big ones. Don't do this with an 18350. Go 18650 and don't push your luck.

2. If you don't own a multimeter, go buy one.

3. Know your amp limits on the batteries you're using, check the voltage on those batteries and check the resistance on your coils, learn the math to figure out your amps, watts, volts, etc. Operate within the manufacturer constraints and if you decide to "push it" do it once or twice then stop.

4. Check yoru battery constantly. Take 10 hits on some super vape set up... check the battery. Change it at the appropriate time.

5. If the battery gets hot... stop, take the battery out, set it someplace not flammable, wait 5 minutes and check on the battery, if it's hotter find a safe place to put it where it's not going to do any damage, wait for the battery to finish doing whatever it's gonna do (theres a variety of things that 'could' happen at this point) and when it's done, clean up. If you don't know how to clean up a failed battery, google it.

6. If you make a video of your phat clouds... please, put a disclaimer on it, some info other than 'omg look at teh clouds' that tells brand new vapers that you're doing this with the proper information and that they should not "try this at home" so to speak.

I want y'all to be safe, I also want y'all to have fun which is why I'm not saying "Don't do it!" or being one of 'those guys'. but please, for the love of vaping, don't monkey see monkey do this stuff unless you've educated yourself on all the factors that go into it and how to mitigate risk.

(*)Yeah, I think you missed part of what I was sayin about batteries not being intended for our use.

The majority of the 'nicer' batteries we're picking up, specifically the panasonic, sanyo, efest and AW batteries are not intended for use outside of a protected battery pack. Panasonic does not sell their CGR18650CH for use as 'just a battery' it's sold to pack manufacturers, some of which turn around and sell the bare cells. AW would be one of those folks, Efest relabels panasonic, samsung, and sanyo cells which is why they're good cells... but they're still not intended for single cell use outside of a protected pack.

It doesn't mean they're not safe, if they were dangerous we'd have a lot more instances of them going snap crackle or pop but they need to be treated with respect.
Quote Originally Posted by lctrc View Post
How to make sense of a battery's C rating:


tl;dr = Multiply C by mah, then divide by 1000 - that's the maximum amperage continuous discharge the battery is rated for.

Keep in mind that ratings may be an average not a minimum, and a manufacturer could be rating their mah and/or C 'optimistically'. Any individual battery may fall on the undesirable end of the bell curve.