Battery Safety and Ohm’s Law

Ohmschart

So you recently purchased your first mechanical mod and then realized you had no idea that it took batteries or had no idea which batteries were going to be safe with it? First of all, congratulations on your first mech mod but, read this first: A Basic Guide for Mechanical Mods and Safety.

Already read it? Great, you’re definitely on the right track now and we’ll teach you as much as we can about batteries, battery safety, ohm’s law, and how to determine how safe your coil or atomizer/clearomizer/cartomizer  is for the battery you are using.

With regards to vaping, the battery is the most important item, far more important than your coil, or multiple coils if you have them. Batteries are even more important than the debate over the superiority of wick materials (cotton, organic cotton, silica, mermaid hair – whatever). So if you are looking to get into mechanical mods, or thinking about pushing the limits of your current set-up, or are completely unaware of what your battery can even handle – then this article is definitely for you.

Battery Safety Basics

Do not overcharge or over-discharge.

To combat this, do not leave your batteries in any charger without supervision. Make sure that you are able to see or check on the charger every 15-30 minutes. This way when the charger indicates that the batteries have been fully charged, you can remove them from the charger. Leaving batteries in a charger all night long or longer can cause them to be overcharged, which can result in battery failure. Charging your battery over 4.25 volts can shorten its life-cycle and going over 4.5 volts can cause it to burst. Cease using your charger if this ever happens.

Our recommendation on a good charger: Nitecore D2 Charger (2 Bay) or Nitecore D4 Charger (4 Bay)

Recharge batteries with a resting voltage below 3.6V as soon as possible.

Leaving LiIon batteries in a discharged state will incur irreversible damage – creating a loss in capacity and a loss in cycles.

Determining the exact voltage can be tricky, unless you have a multimeter. If you are delving into the world of mechanical mods and RBAs (ReBuildable Atomizers), or making your own coils, a multimeter is a must have device because you can use it to test your coils and your batteries. Sure, you can always use a battery tester, but the majority of battery testers are not equipped for the types of batteries that are used in mods, or even test batteries under load condition.

Do not short circuit your batteries.

Short circuiting can cause a huge surge of current that will potentially burn out your battery, damage your mod, or even your face!

Short circuits happen when the voltage from a battery is discharged through a low resistance wire at a discharge rate that exceeds the battery’s upper amp limit. Short circuiting a battery is very close to what a mechanical mod with a sub-ohm coil is doing, except you are trying to keep the resistance under the upper amp limit – there’s a fine line that you have to be careful of when sub-ohming. 

Do not let your batteries touch each other or other metallic items. 

Keeping your batteries loose, such as in your pockets, is a good way to have your batteries fail and seriously harm you. There are battery holders and covers to keep your batteries safe. Get some – now.

Do not dispose any battery in a fire.

This is just common sense people. There are dangerous chemicals in batteries. If you try to burn your batteries they’ll release dangerous fumes and will probably explode. Do yourself, and the rest of the world, a favor by taking your old batteries to a battery recycling center.

What’s In a Name?

Let’s take a look at the specifications of AW IMR batteries for a moment:

IMR16340 Specifications:

Nominal Voltage : 3.7V
Capacity : 550mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 1.5A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 4A
Operating Discharge Temperature : -10 – 60 Degree Celsius

IMR14500 Specifications:

Nominal Voltage : 3.7V
Capacity : 600mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 1.5A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 4A
Operating Discharge Temperature : -10 – 60 Degree Celsius

IMR18350 Specifications:

Nominal Voltage : 3.7V
Capacity : 700mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 2A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 6A
Operating Discharge Temperature : -10 – 60 Degree Celsius

IMR18490 Specifications:

Nominal Voltage : 3.7V
Capacity : 1100mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 3A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 15C
Operating Discharge Temperature : -10 – 60 Degree Celsius

IMR18650-1600 Specifications:

Nominal Voltage : 3.7V
Capacity : 1600mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 4.5A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 15C
Operating Discharge Temperature : -10 – 60 Degree Celsius

IMR18650 -2000 Specifications:

Nominal Voltage : 3.7V
Capacity : 2000mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 2A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 10A
Operating Discharge Temperature : -10 – 60 Degree Celsius

Determining Your Maximum Discharge Rate

The most important specification to pay attention to is the “Max. continuous discharge rate” for each battery. Each battery has a number and a letter, either measured as A or C (30 Amps or 15C). Look at the IMR18650-1600 for example. If your battery has a maximum continuous discharge rate of 15C, this means the battery is rated for 15 times the capacity of the battery measured in amps. So a battery that sits at 1600mAh, which equals 1.6Ah will have a max continuous discharge rate of 15 X 1.6 = 24A. There is a chart below which has the max continuous discharge rate in Amps of some common batteries.

You should always determine what your max continuous discharge rate is in Amps (which many of the new and popular batteries have already) to keep your math consistent and mind at ease.

How To Use This Information Effectively

Knowing the max discharge rate in amps is only half the battle.

How do you know if your coil or atomizer/clearomizer/cartomizer won’t short circuit your battery? Simple, use this equation: battery volts / the ohms resistance of your coil = your actual discharge rate.

If your actual discharge rate is less than the maximum discharge rate you calculated earlier, you’re in the clear. If it’s not, you need to suck it up and rebuild a higher resistance coil.

Let’s take a closer look using the 18650 1600mAh battery again (for the sake of continuity). If you took a freshly charged 18650 1600mAh battery and tossed it in your mechanical mod with a very limited voltage drop, and put a .2 Ohm coil on top, you’d be running at 20 amps. To figure out this math you take the voltage running to your coil from your battery, which lets say after a full charge, the multimeter shows that the battery is sitting at 4 volts. Now, divide by the ohms of your coil. The number you get is your total amps. In this case our math is 4/0.2 = 20. So we now know that running this exact setup will push our battery to 20 amps, just 4 amps under its max discharge rate. If you were using a different battery capable of less power under the same circumstances, you would be asking for complete battery failure and the chance of possibly hurting yourself.

Safety PSA: Resistance in coils can have a variance of 0.2 Ohms in either direction, or +/- .2 Ohms. This means that if you build a 0.2 Ohm coil, you have to account for that +/- 0.2 Ohm variance. The coil in the above example at .2 Ohms is an incredibly unsafe coil, and I would not use nor suggest that anyone use such a coil. Because of this, I would not recommend anything lower than a 0.4 Ohm coil for 18650 1600mAh battery.

Equation Recap

Let’s take a look at everything you’ll have to calculate in order to determine your coils safety in order.

1. Calculate your battery’s capacity in amps: capacity in mAh / 1000 = capacity in amps

2. Calculate the maximum discharge rate if measured in C: maximum discharge rate = (battery capacity in amps) x (continuous discharge rate)

2. Measure your battery’s volts with a multimeter.

3. Measure the Ohms of your coil and subtract .2 to account for the +/- .2 variance.

3. Calculate the discharge rate you’ll have with the coil you’ve built:  battery volts / Ohms = your actual discharge rate

4. Check to make sure that the actual discharge rate is LOWER than your battery’s maximum discharge rate.

But What About Other Batteries?

Below, I have listed out the commonly used batteries by brand with their max continuous discharge rate in amps, to make your math a little easier. However, remember that you’ll need to test the battery’s volts before AND during use in order to make sure that the coil you used is safe.

The best batteries for sub-ohm vaping are generally Sony VTC 4 or Sony VTC 5, although they are often out of stock. In that event I usually use an 18650 Efest 35A.

Battery name and mAh Continuous Discharge Amps
AW IMR
Aw 14500 600 mah 4 amp
Aw 16340 550 mah 4 amp
Aw 18350 700 mah 6 amp
Aw 18490 1100 mah 16 amp
Aw 18650 1600 mah 24 amp
Aw 18650 2000 mah 10 amp
Efest IMR
Efest 10440 350 mah 1.4 amp
Efest 14500 700 mah 5.6 amp
Efest 16340 700 mah 5.6 amp
Efest 18350 800 mah 6.4 amp
Efest 18490 1100 mah 11 amp
Efest 18650 1600 mah 30 amp
Efest 18650 2000 mah 10 amp
Efest 18650 2250 mah 10 amp
EH IMR
EH 14500 600 mah 4.8 amp
EH 15270 400 mah 3.2 amp
EH 18350 800 mah 6.4 amp
EH 18500 1100 mah 8.8 amp
EH 18650 2000 mah 16 amp
EH 18650 NP 1600 mah 30 amp
MNKE IMR
MNKE 18650 20 amp
MNKE 26650 15 amp
Samsung ICR INR
Samsung ICR18650-22P 2200 mah 10 amp
Samsung ICR18650- 30A 3000 mah 6 amp
Samsung INR18650-20R 2000 mah 22 amp
Samsung Samsung INR18650-15mm 1500 mah 23 amp
Sony
Sony US18650v3 2150 mah 10 amp
Sony US18650VTC3 1600 mah 30 amp
Sony 18650VTC4 2100mah 30 amp
Trustfire IMR
Trustfire 14500 700 mah 2 amp
Trustfire 16340 700 mah 2 amp
Trustfire 18350 800 mah 4 amp
Trustfire 18500 1300 maah 6.5 amp
Trustfire 18650 1500 mah 7.5 amp
Panasonic
NCR18650B 18650 NP 3400 mah 6.8 amp
NCR18650PF 18650 2900 mah 10 amp
NCR18650PD 18650 2900 mah 10 amp
CGR18650CH 18650 2250 mah 10 amp
Orbtronic
Orbtronic 18650 2900 mAh 10 amp
Orbtronic 18650 SX22 2000 mAh 22 amp

209 comments on “Battery Safety and Ohm’s Law

  1. Thank you so very much. I am glad i found this article as i am researching on my shift to RBA and mechanical mods.

    Reply
  2. Efest imr 18650 2000 I charge to 4.2 I use it then when should I recharge the battery. AT HOW MANY VOLTS LEFT

    Reply
  3. Please tell me if i have this right. If i take a sony vtc5 with a max discharge rate of 30 then multiply that by the amp hours which is 2.5 giving me a total of 75 making 75 amps my total discharge rate I need to stay under?

    Reply
    • Hi Jon, you will want to stay under 30 amps, not 75. To make sure you are within the 30 amps you want to take the voltage of your battery (let’s say it’s 4 volts) and divide it by the resistance of your coil (let’s say it’s .5 ohms) and that will get you 8 amps which is below the 30 amp max discharge.

      Reply
    • A max of 30A is what it says it is, regardless of ‘C’. At 3.7V, your MINIMUM coil resistance is 0.12R, for a power output of 111W, which is insanely hot & will likely destroy your tank/dripper, & probably damage your mod too. Anything over 30W (8A @ 3.7V) is overkill for vaping, & likely to be dangerous, so I recommend people keep their coils to a MINIMUM of about 0.5R.
      And as the article points out, it’s very difficult to accurately measure small resistances, so you should always err on the safe side, & assume that your meter is reading high, especially as the test leads also contribute their own resistance (typically +0.2-0.5R) to the reading.

      Reply
      • I use the VTC5’s and they are the ONLY battery’s i use luckily i bought 10x pairs of them when they came out because you cannot buy them any more since Sony no longer makes them, and what is for sale out there are counterfeits and fakes (WHICH ARE EXTREMELY DANGEROUS BECAUSE NO ONE KNOWS THE BUILD QUALITY AND THEY CAN EXPLODE IN YOUR FACE THE FIRST TIME YOU HIT THAT FIRE BUTTON). i HAVE VAPED ALL THE WAY DOWN TO .14 OHM on these batteries with no issues, however I prefer a vape around 50w, BTW Lionel in my experience I have done super low build like that MANY times and NEVER have I killed anything I’ve vaped all the way up to 100 watts with absolutely no issues. Maybe with cheap MODs or mechanical stuff yeah but I don’t know for sure I don’t use mech mods never have and never will for that reason theres no control, use good stuff and high quality batteries like VTC5’s or currently their best replacements the LG HE4’s and you won’t have any issues. there’s no minimums if you know what you are doing because everyone has different preferences, even I every quite often like a nice .30-.35 or so vape using my beautiful digital IPV3 MOD capable of reaching 165 watts at .08 ohms with no problems with it’s YiHi chip as proven many many times @ 150w – .1 ohms without a single failure (the problems is there are no batteries that can hold that so I’m not going after .08, I’ve hit .14 with my VTC5’s but I like my lower jaw right where it is thank you very much). Bottom line do your research, be safe, find your own sweet spot and maybe a few others you like to switch up once in a while, and most importantly use high quality stuff unless you want to be missing a hand or blow a hole in your neck or jaw. I will say this much though, YES IT is MORE dangerous and your risks go up substantially below .5 ISH (i’d say .4 ish) but again as long as your equipment can handle it, and you know what you are doing and have the experience, by all means go for it but NO ONE BUT YOURSELF IS RESPONSIBLE FOR WHAT FOLLOWS!!!!

      • Different mod types should be addressed here. Like boxes running dual/triple parallel batteries or dual series which are throwing a consistent 150w unregulated. And some info needs updating. The new subtanks can handle up to 100w depending on the coil but I don’t go over 65 personally. I also don’t really have a build over .2 except my onslaught but that’s because of the triple coils, so it’s .33. Otherwise I use between .2-.3 and my vv/vw to enjoy my flavors instead of some people always running .1 builds thinking it’s so cool when really it’s just being a douche. I’ve got enough attys that will handle a pure cloud chasing build but I don’t compete so it’s a for fun thing if I do that. My goto gives me clouds and flavor, I love my sig150. Just ordered a smok 65w for like $40 so that’ll be used more probably since its smaller and has a charge port + passthrough so I can charge and vape. Only one battery in it and that’s just fine, most vv mods hitting 30w max cost more than this 65w one. So great. Easier while driving too.

      • Lionel, I own a vapor shop. I run imren 3000mah 40amp batteries in my mech mods. We use to have the sony’s. Hated them. LHE4’s are without a question better than a Sony. My opinion is imren or nothing. They can handle .08 easily. In a mech mod. Check them out and you will sell those junky sony’s. They don’t want to be a part of the vaping community so they can keep them, take care.

      • Sorry, but .2-.5 margin off error for ohm readings is unheard of. Telling people to never vape over 30w is baseless fearmongering as well.

    • So if i put a .15 ohm coil in my subtank, with a 30 watt battery, would it be safe?

      Reply
    • I have read your wonderful posts regarding proper usage and safety for these batteries. I have what is likely to be a dumb question but I am mechanically challenged (to put it mildly)! One of my 18650 2500mAh 3.7V batteries had its blue skin torn. May I take it that this battery is no longer safe to use and should be properly disposed of? I will be so grateful for any assistance!!

      Reply
  4. so let me get this straight, with a sony vtc4 (30A) max discharge. A .2 ohm coil would be the absolute lowest you could go am I doing correct math here, at 4.2 volts the max charge and . 2 ohms = 21A. and then obviousley it would get lower as the battery slowly dies.

    Reply
  5. Thanks alot for this very informative article.

    I’d like to ask about VV/VW devices how do they perform with low ohm’s vaping ?
    is it advised to go with these devices rather than mechanical mods in terms of safety if something went wrong !?
    and in terms of ability to perform well with low ohm’s vaping .
    As far as I know that some VV/VW devices cannot operate under 1.5 ohm’s , correct me if i’m mistaken !

    I’ve been using Innokin MVP 2.0 + Aspire Nautilus clearomizer , it’s quite a decent combination for me

    I’m not a newbie neither i’m a Pro in vaping stuff, but I feel I should take it to the next level in vaping, that’s why I wanna begin building my first RDA which is IGO-M

    any advice would be most appreciated
    thanks again

    Reply
    • Hi Momado, in terms of safety, a VV/VW device is safer since it will generally have safety features built into it. The main safety features usually prevent sub-ohm vaping (less than 1 ohm) and have an auto shut off when your battery voltage gets too low.

      The DNA 20 and 30 VW devices allow you to vape at around .3 Ohms minimum, anything less will shut it off.

      If you are looking to get into mechanical mods, definitely have an understanding of Ohm’s Law. The most important thing to make sure is that the resistance of your atomizer is not too low for the max continuous amperage of your battery. I like to build at .5 ohms and use a Sony VTC4 or VTC5.

      Also be sure to get a good Ohm reader.

      Reply
  6. When you say .2 ohms, is that really 2 ohms? Or would .2 (point 2 ohms) be considered sub ohm? Just want to make sure I have this straight!

    I’ve just ordered a mec mod, and don’t want to blow my face off.

    Would I technically be safe no matter what battery as long as I’m not going “sub ohm”? I normally build coils from 1.2 ohms to 2 ohms.

    Reply
    • Hey Ryan, it’s .2 (point 2) ohms or 2/10ths of an ohm. That would be sub-ohm. A mech mod isn’t really going to work well with anything above 1.5 ohms. On a fully charged battery at 4.2 volts and a 1.5 ohm coil, you’re only using 2.8 Amps (4.2/1.5=2.8) or 11.76 Watts of power (4.2X2.8=11.76)

      Reply
  7. Thank you for this information!!! I’ve been vaping for a year, but got into modding and sub ohming recently. I have a mechanical background but I am mathematically challenged when it comes to electronics. I’ve read several articles concerning all of this, but your explanations and information has been the easiest to understand and comprehend. Again, thank you!!

    Reply
  8. I saw Rip from riptrippers do a .09 build on a V3 Flip using Sony 18650 VTC5 batteries. Maybe my math is off but the VTC5 max continuous output is 30 amps. With Rip’s build it would be pushing 41.1 amps. According to your equation this is extremely unsafe. I have seen some subohm vapers doing builds with the VTC5 at .08, .07 and even .04. Can you please tell me how this is accomplished without blowing up the mod?

    Reply
    • Hey John, so VTC5 has a max continuous discharge rate of 30 Amps but a “pulse” rating of up to 60 Amps. Pulse ratings are for short bursts of energy (generally less than 30 seconds, which most vapers would never hit), so that is why the battery is not venting. However I don’t like to recommend going up to the max pulse rating of a battery since there are a lot of cloned batteries being sold, which may not have been built to the standards of an authentic battery and battery health is a very important factor.

      Reply
  9. I’m really interested in this calculation of maximum discharge rate because I wasn’t aware of such number. I only knew about maximum continuous output which I only use Sony vtc5 so that’s 30 amps and I would use an ohms law calculator to figure out how low of a coil I can build which is .13 ohms at 28amps. Now this maximum discharge rate would explain why I just saw riptrippers build a .09 ohm build with a single Sony vtc5 in his new cloud chasing 101 part 2 video with no I’ll effects. Based on ohms law this .09 build is running at 41amps which I thought was way over what battery could handle but if maximum discharge rate is 78amps then this will not exceed what battery is truly capable of considering you are only running battery for 5 sec tops for super sub-ohms. A build at .05 puts max discharge rate at 74amps which clearly would be maxing limits of battery (78amps) and could cause it to start venting. Let me know what you think Brennen.

    Reply
    • Hey Kevin, so the calculation that you are referring to is actually for when your battery’s max continuous discharge rate is measured as 15C and not 15A, I’ll change the language in the article to make that more clear. And I responded to another comment about the same thing. Rip was “ok” because he is basing it off the max “pulse” discharge which for the VTC5 is 60 Amps. I’ll never suggest to build a coil where you would be hitting the “pulse” rate since battery health and other factors can make that number much less than it really was rated for.

      Reply
      • Yes I agree, the battery voltage is not consistent and if not at a full charge or if battery is old and near end of life cycle it could definately cause if to vent. Its a matter of when not if.

  10. Sorry I didn’t see Jon’s comment for some reason but that’s funny we were thinking the same thing, thanks Brennen this was great info!

    Reply
  11. So I have a question. I’m looking at buying a MNKE IMR 26650 battery, but the information you posted on here is different than on the website I am buying, and any website for that matter. Some websites are saying it’s a 30 A, which, if my math is correct, with 3500 mAh, would have a 105 A maximum discharge rate? That’s extremely high, and seems almost too good to be true. But then you’re saying it’s 15 A, and I looked on another website that says it’s 20 A, and I have no idea which source would be correct, and if my information is correct. Help?

    Reply
    • Hi Luke, we don’t have any information on the MNKE 26650. But if it says 30A, then that’s probably what the max continuous discharge rate is. The only time you would do the calculation is if the max discharge is written as C. But in this case it’s already 30A not 30C. If your battery already rates the MCD in Amps then you don’t need a calculation, if your battery rates the MCD in C then you’ll need the equation to convert it to Amps. Does this make sense?

      Reply
  12. So I was wondering if you were using a dual unregulated box mod, how would you calculate the maximum continuous discharge for the whole setup? Would you just multiply the single batteries am limit by two or is there more to it? Thank you for the info.

    Reply
    • Hey Shane, that’s a good question, I don’t know. Maybe someone else here can help with that question.

      Reply
    • AHA! the question I keep returning to this page for! I’m in this same boat and DO hope someone knows or finds the answer, and shares it with us. Sorry I don’t have an answer and am just filling space but I will keeping digging and try to find the answer we’re ALL waiting for.

      Reply
  13. Hello, if I have a battery that has no markings for discharge rate or c rating is there a way of calculating mathematically or on a multimeter?

    Thank You

    Reply
  14. Greetings,

    Great info here, thanks so much sir! :)
    If i may, i would assume (as a noob here), that a new mod user should be safer if playing with minimum 2.0 ohms? Higher the ohms is more safer, in cost of loosing battery power fast and pleasure of vaping? Is it okay when my battery power at half level, and keep using it? Or i should always keep my battery at full power? I have nemesis with dome (RBA), and my coil is at 2,4 ohms, sometimes 3.0 ohms (when i check it on my ohms meter), with efest IMR 18650 3.7V LI-MN 2500mAh 35A (purple efest)… any recommendation, please? I’m totally new here, lack of english, lack of everything about electricity :)) The only thing i always put in mind, especially when building my coil is: stay away from sub-ohms build ehehe.

    Thanks so much sir, and i’m really sorry for my english.

    Reply
    • A mechanical mod and an atomizer at 2 ohms isn’t going to give you a very good experience. With a fully charged battery at 4.2 volts you would only be using about 2.1 amps. If you’re using the 35A efest 18650, you’ll be fine to go down to .4 ohms which is where I like to build my coils with that battery.

      Reply
    • English is great. You did just fine

      Reply
  15. Hi so my battery is a 18650 and i’m planning use a clearomizer, Aspire Nautilus with BDC coils, will this work out without short circuiting the battery.

    Reply
    • Mechanical mods aren’t really meant for clearomizers, but using a Nautilus with stock coils would not be an issue. Your vape experience may not be very good though.

      Reply
      • Hi
        I got my relative a aspire nautilus BVC Clearomizer with a KTS+ telescopic mod , she will be wanting to use it as small as she can, so I’m thinking 18350 aw IMR this size , her coils will be (I think ) 1.8 and 1.6 , no lower ,
        But my wife is using a stingray x with 18350 tangsfire at 1.6 on the aspire nautilus and complains of sometimes weak draw and mod becoming a little heated , please can you tell me why this is , also should I up the size of her batteries to a 18500 , same with the kts+’for my relation , would this improve there draw , also is this set up safe for both , as they wont be going below 1.6ohms coil
        please can you email me the answer as I’m not sure how I came across this site , and not sure if I can find it again to get my reply
        Thanks a lot

      • You should be fine with a 1.6 ohm coil and an 18350 battery. The nautilus performs much better on a regulated mod like an eleaf istick or similar though.

  16. How many coils (4 rap) can I put on my tank (D-Eagle) while i’m running a Efest 18650 2000 mah?

    Reply
  17. Hello. I am new to mechanical mods and rba’s and im trying to understand and figure out what is the lowest resistance in coils i could go with an 18650 2500mAh battery that has “35A” written on it. Also, what exactly does the 35A indicate?

    Reply
  18. Need some reassurance please. My next coil setup will be roughly .75 ohms. Using an ohms law calculator and at 4v it states that my amp draw is 5.3 with 21.3 watts of glorious heat. I plan to use a 26650 high drain 4200mah battery that states a continuous discharge rate of 50a. I believe that with the above coil i am within the safe limit? So i ask….am i? Sorry my maths is shocking (no pun intended) Could i even use a battery with either a 30a or 20a continous discharge rate? Thanks :)

    Reply
  19. Hello.

    First of all, thank you for this information. I just got into rebuildables and mech mods recently and this has done a lot to put my mind at ease. I purchased 2 Sony VTC4 30 AMP batteries, a 454 Big Block RDA and a Stingray X Limited Edition Black mechanical. I was worried that my .5 Ohm Dual Coil (1 Ohm per coil) would cause issues but now I know that the max amp limit of these batteries (at 30 amps) puts that 8.4 amp draw at 4.2 volts well within the safety limits of the VTC4.

    However I do have a question about recharging. I picked up an Intellicharger i2. What I would like to know is, when should I remove the currently in use battery to charge it? The nominal power is 3.7 volts. Does that mean I shouldn’t discharge beyond 3.7 volts? Does it mean I should try to get it as close to 3.7 volts before charging? Can I use the battery beyond that, to say 3.6 or 3.5 volts and still be safe? I know you touched on recharging a bit in the article however I didn’t find that part clear or detailed enough to answer these questions.

    Reply
  20. First of all, thank you very much for the easy to understand information in this article. Just one thing: How can I find the Maximum Discharge Amps in a battery? I’m a bit confused where in your example you used high C (15C), but when I tried to looked up my battery in the internet (HGB 18650 220mAh 3.7V), the max discharge amp is only 2C, which means the max I can have is only 2 x 2.2 = 4.4A. Does this sound right? I am currently running my hammer mod on a 0.69ohm single coil, which means the actual discharge amount is 4V/0.69 = 5.79A, which is already exceeding the max my battery can handle. Am I right on this? Appreciate your help very much !

    Reply
    • Hi Gyo, yes in that case you are already exceeding the limits of your battery. I would always recommend the Sony VTC4 or VTC5.

      Reply
    • If your talking variance that is the difference or the flow and current and power switching directions take the steps to find the voltage which is the flow then the current which is the amps then the power which is your coil. Then go back and concentrate on your battery don’t exceed the limit.

      Reply
  21. Great info here. It’s nice to finally have a decent answer as to how so many out there get away with extreme sub-ohm vaping, and why “explosions” or venting incidents are relatively (surprisingly) rare, and that’s the pulse discharge rate. Makes total sense.

    Now – I am still trying to figure out whether putting two 18650s in series (doubling the voltage and mAh) also doubles the max discharge rate – like 30A is then 60A. Or, does it simply reduce the pressure on each battery, hitting them as half the amperage they would have been handling alone?

    In a regulated box mod we have, it’s dual 18650s in series, and has a VV dial without readings. I assume it goes up to 6V or something, thus limiting the power of 8.4V from the two batteries. But at a .5 build on our atty, would 6V run at the 12A indicated by Ohms Law, or at a different rate because the batteries are “stacked” or in series?

    The person we got the mod from said never to go below .5 ohms. But I have a hard time piecing that warning together in my head considering .3 ohms at 6V is still only 20A. Neither my wife or I even like vaping anything under.4 or .5 anyway. But I like to know what I’m working with.

    Thank you!

    Reply
    • Hi Jeff, that is a good question, maybe someone a bit more knowledgeable about batteries in series vs parallel can answer that, I don’t know for sure.

      Reply
    • Stacking batteries in series like that is dangerous with out very careful care in how you are doing it. The batteries used need to be paired for life. I.E. Brand new when you start, and always charged together, and swapped in their placement in your mod after each charging. 1 battery should be labled A for examble, and the other B. And the first time you use them, A top and B bottom. Then next charging B top and A bottom. That way they both are worn the same. In series what can happen, is one cell will deplete it’s life cycle before the other, and one will begin discharging into the other… you could have one cell reach critical charge and not be aware of it. As far as what being in series does to the discharge rate, I’m not real clear, I’m still learning about Stacking and have been very cautious about it so far.

      Reply
    • Hello Jeff, I noticed you posted that batteries in series have doubled voltage and mAh. This isn’t completely true. In series, batteries do have doubled voltage, however, they retain there native mAh, if you’re using the same battery(which is very highly recommended). Using batteries with different mAh capacities would result in an average of the two(mah+mah/2) mathematically. Batteries in parallel retain there native voltage, but double in capacity. As for your question on ohms law, and whether or not batteries in series has any affect on amp draw within the system, it does not. 12A is 12A either with one battery or a bank of 100. I have been doing some research on series and parallel batteries but alas. I too have the same question unanswered, and that is what the heck happens with the amperage rating of batteries in series.

      Reply
  22. Hey I’ve got a efest 18650 35a purple battery.

    I’m running at .15 ohms dual coil. Is this bad or something?

    Reply
    • Hey Ryan, the 35a on the purple efest is the pulse rating and not the “safe” continuous rating that most people follow. That efest is generally rated for 20 amps continuous according to efest themselves. So at .15 and a fully charged battery at 4.2 volts, you’re hitting 28 amps which is within the pulse rating, but above the “safer” continuous rating that I would always recommend. If you continue to build at that resistance, I would recommend a Sony VTC4 or 5.

      Reply
      • I have an efest battery that isn’t listed in this article,it a 18650 3100mah 3.7v li-mn. I normally build between 0.30 and o.50 will these batteries be OK?

      • A battery with that high mAh is bound to have a lower discharge rate and therefore be less safe at low resistances, I wouldn’t go any lower than .5 but even then, its very important to know your battery’s continuous discharge max rate. If you do build at .3, i would recommend Sony VTC4 or 5 or the cheaper but slightly less performing(but still safe) Samsung 25R.

    • Shadow from the starlight

      That’s low man you’d be safe running at 3wraps which is .75ohms or 4 or 5wraps.

      Reply
      • I don’t know about that shadow, I run a dual 7 wrap macro coil 22 gauge with a purple efest and the coil runs about .24 on my ohm reader (maybe even closer to .2) and it works fine and I have had no problems so far…but I will prob. want to pick up a VTC4 soon because i want to try a dual parallel coil with 22 gauge, and 7 wraps…

      • I just got done building and firing my own Stingray for the 2nd Month now, I’m running on 6 wraps a dual parallel 24 gauge coils @ roughly 0.02 OHMS if my ohm reader is to be believed… This is great and puts out amazingly, however the downside is that after about 4 or 5 hits, the Stingray becomes so fricking hot that its like holding onto an oven rack while the oven is on… Don’t know if its because the Mod isn’t built for such low OHMS or what but I’m definitely getting a box now.

      • That’s because at .02 ohms is literally .01 away from your battery exploding. If you have a Sony VTC4 on a mech mod, I think vaping at .1 ohm is safe, and about as low to go unless you’re going in a cloud comp. Anything lower gets riskier and riskier. I think the lowest I’d go on a mech mod would be .08, in a single 18650 mod. If your ohm meter is actually reading at .02, then I’m surprised you still have a face, otherwise I’d get a new ohm reader. But you don’t have to switch from unregulated to regulated, like I stated, a coil build reading at .1 or higher is fine on a mech mod I believe, and the math agrees with me.

      • I run a .1 on a 18650 and Iv been doing it for months nothing bad has happened

      • Afraid to say it friend, but something will… be safe man, for all our sake.

      • Ok, lets get something straight here. On a 30 am battery you can vape down to .08 safetly. How do i know? well, look at all the pro coil builders. they never have coils above .18 ohms. The problem is experienced vapers are ok with this, but some dumb kid who doesn’t know what he’s got will turn his mech mod into a pipe bomb, literally. Point is, most people are overly safe, which is good, but do try to get your facts straight. Lying about this is bad, people find out they’re being lied to then they get indignant and go way too low….i vape around .08-.2 ohms. safely. that’s all

      • Famous last words!

    • 32 gauge 2 coils 9 wraps each same batt. Vapes just fine don’t go over 40w

      Reply
  23. Khristopher Harris

    Hi I just want to know the lowest I can go with the sony vtc4 and vtc5’s is it .12?

    Reply
    • I wouldn’t go any lower than .15 with those batteries. Even that is such a hot vape that I wouldn’t recommend it either. Those batteries have a 30 amp continuous and 60 amp pulse, so you would be in the pulse rating at a .12 resistance and a fully charged VTC4/5.

      Reply
  24. Hi there, thanks for the fantastic information. I have been vaping for about half a year now on a regulated vv/vw mod and have been looking to switch to mechanical mods. My more savvy vaping friends all reccomend the VTC5 batteries above all others. What makes the vtc5 the undisputed champion of all 18650s? Does it have to do with build quality, or just that there are no other IMR batteries with the mAh and discharge amps that the VTC5 has?

    Reply
  25. Hi there, thanks for the fantastic information. I have been vaping for about half a year now on a vv/vw mod and have been looking to switch to mechanical mods. Are there any batteries out there that match the VTC5 in terms of mAh and amp discharge rate? Authentic VTC5s seem to be hard to get ahold of these days but there does not seem to be a comparable alternative.

    Reply
  26. So if I’m buildinding a dual coil do I double the math? So at 30 amps each coil should be at .3 ohms max for a 4.2a output?

    Reply
  27. I understand the article quite well but I have one question. Does the maximum discharge rate and max amperage change in a variable voltage mod? I have a vamo v5 and id like to run a 0.7-1.2 ohm coil for a lot of vape production but I’m unsure of what wattage and voltage it should be set to.

    Reply
  28. Hello how are you?
    First of all thanks for the informations. I would like to know if I use a coil on .8 and other of 1 ohm its this one safer in the same battery? The battery can handle this two coils, but on the first one looks hot, not too hot, but it concernes me. Thank you so much

    Reply
    • What battery are you using?

      Reply
    • Sid shadow from the starlight

      I’ve seen people using double batteries in mods for example the Odysseus and the iAtty were used in this fashion and were a good 10 to 12 inches long so yeah it’s been done to help you check out Rick wechsler on Odysseus and iAtty review on youtube bye.

      Reply
  29. Hi,
    I’m quite new to mech mods and I don’t know too much about physics,
    so I was wondering,
    I have an Efest High Drain 18350 battery, 800 mAh on 3.7V and a coil build reading at 0.3ohms
    Is it safe for me to use this 18350 on this particular build, and how low could I go in terms of ohms without risking anything?

    Thanks

    Reply
  30. So my batterys I should let them charge up 2 4.2v that’s when my charger tells me there ready but what volt level can thay. Go down to be for I need to charge them again

    Reply
    • You should change out [and recharge] your batteries once they fall to 3.6 volts. I personally change them out a slight bit before then, when I start getting “late” fires (the coils start to take longer to heat up as the volts drop from your batteries).

      Reply
  31. Hello Brennen,

    Great information! I recently started vaping with a mech and would like your input. If I am vaping off of a LG 18650 HE2 2500 mah battery with a continuous discharge rate of 20 amps, am I ok vaping off of a .3 ohm coil? Also, what would you recommend to be the lowest ohm setup for my battery? Thank you

    Reply
  32. Hi,
    I’m curious if my set up is safe or not. Running a copper stingray H-cigar clone with a legend clone RBA. The coils I’m using are dual parallels, made with 24 gauge kanthol, and they ended up reading .14 – .15 (bounced back and forth between the two) on the ohms reader. Using two different purple efest batteries (listing everything on the labels towards the bottom of the post.). A friend who works in a vape shop built them for me, and he builds his in the same fashion. (He uses different mods and batteries I believe though.)
    Just curious if my setup is safe or not
    Thanks.

    Battery 1: Purple efest
    3100mAh
    IMR 18650
    3.7V LI-MN
    20A
    Discharge current: 20A

    Battery 2: Purple efest
    2500 mAh
    IMR 18650
    3.7V LI-MN
    35A
    Discharge current: 35A

    Reply
  33. so i am running a stingray x clone and a mutation x rda with 20 gauge kanthal wire and I’m at .13 ohms and i would like to know what battery would be best to use for this sub ohm build and also i keep shorting out my batteries when i try to use the hybrid top cap that came with the stingray when using my multi reader to see voltage why does this keep happening

    Reply
  34. Hi nice blog, great info…. I’m a newbie with RDA and Mechanical Mods, I been vaping for about 2 years know and I have the Rebel 1 and 2, three Lavatubes…. and so on. Know I want to change to RDAs and I bought the “All Copper King Kong 26650 Mod” with the “Efest Purple 26650 64A 3500 mAh IMR Batteries” and were planning to buy a “28 Gauge A1 Kanthal Wire” with “100% cotton” to use it with my “EHPRO COPPER TOBH ATTY V3 ATOMIZER RDA/RBA 28 MM 26650”, is this a safe setup? Would like your help on the matter….. Thank you in advance…

    Reply
  35. I am getting ipv mini with aspire Atlantis . I will be using .5 ohm with efest imr 18650 35 amp battery! My question how long can you take a draw off your mod for. I don’t understand this pulse thing. Yes this is my first sub ohm set up. I never take a draw longer then 2.8 seconds & does that set up sound good to you

    Reply
    • Hey Jim, the IPV mini should have a 10 second shutoff or something similar. I never truly trust a pulse rating (and I’ve never been certain of the time that constitutes a pulse) but when that battery is fully charged at 4.2 volts and you have a .5ohm coil you are hitting the 35amp limit at 8.4A which is a safe amperage for that battery. To be extra safe, buy a sony vtc 4 or 5.

      **Edit, the Watts are 35, the Amps are 8.4 which is safely within the battery’s limit.

      Reply
  36. I am receiving ipv mini with the purple efest 35 amp battery for my aspire Atlantis , I am asking on that same set up on that mod can I also use my aspire nautilus 1.8 coil

    Reply
  37. how are the volts and amps affected when it comes to using two or more of the same battery in a setup?

    Reply
  38. What is the max discharge rate of an IMR 18650 2500mAh 3.7v, and fully charged at 4.2v? I am certain I did not calculate it properly at 2500 divided by 1000=25, what am I missing? There is no other info printed on the battery (c) Are my coils safe with this battery if they’re built between .4 and .5? Also I’ve noticed the resistance of my first build has increased from .48 to .59 after only a few uses. Should I be concerned about this? I don’t allow the battery to discharge below about 3.7v

    Reply
    • Hi Libby I actually don’t know the max discharge of that battery. If it doesn’t say on the battery or if there isn’t a “C” rating, it is impossible to know without contacting the manufacturer of the battery. I’m sorry I couldn’t be more helpful.

      Reply
  39. I’m very glad that you have provided this information,I will be back again and again to glean more knowledge. I just ordered the 40 AMP 2300 mAh 18650 From Vamped and really would like to know what ohms are safe for this battery? I’ll be using it with a Nemesis clone and a Aga T2 I am sure it could handle sub ohms however I was thinking more along the 1.2 t0 1.8 range, what are your thoughts.

    Reply
    • Hey Verlin, I’m not sure what the recommended build is on the Aga T2 but generally on a mech and when you are not using a dripper, anything around 1 Ohms seems to be alright.

      Reply
  40. As for Panasonic NCR18650B (6.8 amps/pulse 6 sec 12amps). Can i use this battery to fire up the atlantis in a sx300 mod, firing at 36 watts. My drag is at 3 seconds vape each time. Will the battery blow up since it is within the pulse rating. What does pulse rating truly mean….Does it mean when your amps go up above the max amps of 6.8amps then the batt will start to pulse to compensate? Is this the true meaning of pulse discharge rating where by it will handle up to 12 amps and above that it will start to heat up and vent or explode? Thanks for the explanation in advance. vape on and vape safe.

    Reply
    • So, you are pushing into the pulse limit with that battery and the atlantis. I generally don’t run batteries in their pulse limit since I can never be sure about the quality of the battery. If it was me, I would just buy a VTC4 or something similar with a high 30amp discharge rating. Better safe than sorry. Hope that helps.

      Reply
      • I am running a.6 ohm dual coil the steampunk mech mod with an mxjo 35a…I haven’t heard much about this brand in particular…safe?

  41. im looking into building sub hom builds im wondering if i can do so with a http://www.e-liq.com/products/e-cigarette/maraxus-mod-clone-kit with the http://www.e-cig.com/samsung-2200mah-18650-battery im just wondering because i used ohms law calculator and it says i need a batery with 8 amps and 4 volts in order to run this but can someone please help me really looking to get into making my own builds and such

    Reply
  42. Im running the purple Efest 3.7Volts, 2500mAh on a stock Aspire Atlantis..Is this safe and is there anything I should know or keep in mind..Ive only been vaping for a week. Thanks!

    Reply
  43. I got a pink battery thats an IMR 18650 2600mAh 3.7V. There is no C or A dictating the amps for max continuous discharge. The box said it was a Samsung. Any ideals what it’s max dis. Rate is?

    Reply
  44. I wanted to know if amps ,voltage and may doubles if I have a dual parallel 18650 box mod

    Reply
    • Batteries ran in parallel double the mahs only, volts remain unchanged. Running in parallel increases battery life only. If you have 2 freshly charged batteries at 4.1V each with 2100mah, you end up with 4.1V with 4200mah as your set up. You would still calculate the Amps by mulitplying the 4.1v by your coil resistance. In order to increase volts, you would need to run the batteries in Series. The same two batteries above in series would put out 8.2V with 2100mah.

      Reply
  45. I went through your battery list and I noticed that the highest voltage battery which you listed was only 30 amps. I personally have a Vamped Vapor Cells 40 amp IMR 18650 3.7v 2000MAH battery and I have been vaping for a little over a year, but I was recently watching a build video on YouTube by BananaVape and one build in particular was .07ohms which with a 4.2volt battery would yield a current of 60amps. So I was wondering if there were other high amp batteries out there in the market or if he was just really taking a risk or what. Most of his builds are below .1ohm so he clearly does this on a regular basis and I was wondering if running a battery with a max load of 40amps at that resistance and current would cause the battery to vent and render it useless. I was also wondering about venting and the causes of this event and ways to prevent this. Thanks for your time and I look forward to any input which you or anyone who is current reading this, has to offer. Thanks again.

    Reply
  46. Hey, I’m currently using efest 35 amp and usually doing build .4-.9 ohm build, is it safe?

    Reply
  47. So I am brand new to mods and stuff I just got a kecig k 100 with a nimbus double coil and it has a trustfire 18650 2000 man battery in it. My gfs brother had it and never used it and gave it to me. I just wanna make sure its not gonna blow up in my face lol

    Reply
  48. Hi,
    Thank you very much for all this great information. I´ve read everything and every comment, but I have this question I cant find an answer anywhere…. What happens if I use a 1.8 coil with an Aspire Sub Ohm Battery?
    Thanks in advance for your answer!

    Reply
    • Hey Marcel, that should work fine, but the atlantis is recommended with that battery.

      Reply
      • Brennen, thank you so much for your reply!
        What you said is what I thought, but this is the e-mail I received yesterday from Aspire:
        “Dear Customer,
        Thank you for supporting aspire!
        We don’t suggest customers to use our subohm battery with our nautilus or nautilus mini.for the output wattage is too larger,which will burn out the coil immediately,what’s more,it may damage the connector pin under the base hardware”

        What do you think¡?.

      • I don’t understand why they would say that, the aspire sub ohm is basically a protected mech mod. It has short circuit and under voltage protection, and a timed cutoff, but it is unregulated. You would not get wattages too high for a nautilus with a 1.8 ohm coil. If you divide the voltage by the resistance (ohms) to get the current (amps) and then multiply that by the voltage you get the power (wattage):

        Fully charged = 4.2v
        (4.2 / 1.8) * 4.2 = 9.8 watts

        Lowest charge = 3.2v
        (3.2 / 1.8) * 3.2 = 5.69 watts

        To be honest it would be a pretty weak vape once the battery dropped from fully charged

  49. Whats the lowest ohm build I can use on the mnke imr 26650 battery?

    Reply
  50. I havn’t gone into mods on my website yet, just dealing with Kangertech, vision and Aspire, but looking at getting them, the chart is great to see which batteries are worth buying and which are not, the comments people have made have helped me a lot, top stuff, great page, keep up the good work

    Reply
  51. Using a 26650 battery with a cloupor t6 box mod 100w what kind of amperage would be optimal in a battery for that can you recommend a brand and is unprotected safer than protected with a sub ohm coil like the Atlantis thanks a lot

    Reply
  52. So i noticed that you didn’t put out the specs for an Efest 18650 35A 2500mAh battery, why is that? Its really all i use, and i do builds at below 0.16 ohms, now don’t try to tell me that it isn’t safe because it is and i’ve vaped it for 4 months now with no issues. I’m just wondering why all the specs for other batteries besides what most people actually purchase from their local b&m shops. I’m a cloud chaser by the way as well so i’ve done the extra calculations to be able to maintain safety.

    Reply
  53. I just order my first mod. The IPV Mini 2 70 watt with a mutation x v3 and a purple efest 18650 2500mAh 35amp. Would it be safe to sub ohm down to .2?

    Reply
    • Its safe enough for sure. but 0.2ohms at 70w will only get you to 3.7v that’s fine if you like a cool vape but personally I would run a .3 or .4 at 70w for a little warmer, denser vape.

      Reply
  54. alright, so I have a efest imr 18500 3.7v li-nm battery with a 15a discharge current & i wanna use it with one of my rda’s that have a 0.2ohm build? would this battery blow up in my face while im using it or am I aright

    Reply
    • You need to build higher or get new batteries. a .2 ohm build generally runs at a currents from 18 to 21 amps which is higher than your batteries are rated.

      Reply
  55. I have an efest 18650 3.7v 3100mah 20A and I can’t find any safety info on it anywhere what is the safest ohm rating for this battery in a mec mod?

    Reply
  56. I’m running a vamped imr 18650 40 amp battery on 0.17 ohms with 5 wraps. Was wondering about opinions on this build. Any takers?

    Reply
    • With a high drain battery such as that you should be good to go, just make sure you have a good resistance tester.

      Reply
  57. I have a sony 18650 i think v3 or 4 and a nxjo 18650 35amp and my coils r at .14 is it safe

    Reply
  58. Hey I’m current over my amp limit by .28 is that bad or is it still safe?

    Reply
    • any current over your high limit is unsafe, you would be smart to increase your coils by one or two wraps. with that said… even running very near or right at your batteries max continuous discharge rate is not wise. As an example, I run imren 2500mah 18650’s rated at 40a in a copper smpl mod-derringer rda marriage currently at .21 ohms in dual coil; this build will punch you in the face and its only pulling half my batteries max discharge rate.

      Reply
  59. I have a imren 38 amp battery im running a dual coil 7 wrap 24 guage wire that reads 0.37 ohms. Is that safe ?thanks how do determine how mamy amps my coils are pushing

    Reply
    • that is commendably safe, the only thing i would caution you on is to make sure you’re using an accurate, quality resistance tester (for any build really) but especially under .5 ohms.

      Reply
  60. Hi I’m new to vaping. I just purchased a Series-E Variable Voltage 1000mAh battery from JacVapour. The three variable voltages are 3.7v, 4.2v and 4.8v. Could you please tell me what the recommended ohms ratings is for these three voltages? Thank you very much.

    Reply
    • with that device, you should be absolutely fine with any atomizer or cartomizer out there, just stay away from rebuildables and sub-ohm tanks on that device. I recommend using an aspire BVC tank at 1.6 or 1.8 ohms.

      Reply
  61. I’m running a LGDBHE41865 on a .05ohm build am I in danger??

    Reply
  62. I’m running a Samsung 18650 25r battery on my a.r. mech mod and usually build my coils between .28- .35 ohms. What is the lowest ohm build you suggest for this setup

    Reply
  63. I just ordered the MVP 3.0 with a KangerTech Subtank nano and a ehpro Mr. Owl rda dripper. I was wondering if the ehpro would be safe with .4 coil on the mvp since it only goes down to .4?

    Reply
  64. Hey im kinda new to this i have a trident telescopic mod with a little boy atty, sony vtc4 battery. 18650 3.7v/2600mAh. I want to use 22 gauge Kanthal wraped about 5 times. Is that possible for my mood ir is it going to blow up

    Reply
  65. I run parallel imren 40a 18650s with triple parallel 22 ga dual 5 wrap coils, its a .05. I like the really hot builds that chuck massive clouds. How unsafe Is it?

    Reply
    • I got some imren 40as as well(my first set for my smpl) they perform ok but nothing out there can run ar .05 ohms friend. I do hope you meant .5. IF you DID mean .05 ohms then it is VERY, VERY unsafe! But if you meant .5, that’s plenty safe, those batteries are hardly sweating.

      Reply
  66. I’m running a .12 build in my mech mod, would running an MNKE IMR-18650 be bad? I haven’t tried it yet, but i’d prefer to ask here before I blow myself up

    Reply
    • Hey Jared, you’re pushing about 35amps with that build with a fully charged battery, so I would say be careful.

      Reply
    • My question to you is why? Why build that low, IMO a longer coil in dual or tri-parallel performs better than a dinky super sub-ohm coil; they are also safer, more forgiving and give more feedback on wick saturation, produce more flavor, more vapor, and are a smoother, cooler, less harsh vape. I implore you to try a 24g tri-parallel dual coil build at 6 wraps, its a mighty coil build and ohms in at .3!

      P.S. invest in some name brand batteries(Sony or Samsung), again, safer.

      Reply
      • How did you manage that? By my calculations, a 6 wrap tri-parallel dual coil build around a 2.5 mm bit with 24g comes out at 0.08ohms.
        6 wraps of 28g (same build) comes out at 0.2 ohms

  67. wondering what the lowest (safe) coil build for an unregulated dual-18650 wired parallel. 30A switch . no mosfet or resistor. very basic. wondering the possiblities of sub-ohm

    Reply
  68. I want to upgrade my 50w istick eleaf with a drip tank is this a good idea?

    Reply
  69. I don’t understand this at all. I just bought a Manhattan clone mod, and it will be my first mod. So do I have to buy a ohm meter to be safe? Or will I be OK with out it? And I don’t understand anything about the ohms law, or anything about watts.

    Reply
    • Then you really need to learn..running the wrong battery in the wrong box or mech mod with the wrong build sitting on top can be an express ticket to permanent disability and disfigurement. Take the time to educate yourself before you hurt yourself or someone else…

      Reply
    • You should really read up if you want to build your own coils and or use mechanical mods of any sort. Also you absolutely MUST have an ohm meter/resistance tester to safely build coils! Even if you use a tank with the ohms clearly listed on the coil heads you really should know and understand ohms law and how your atty reacts to your mod; know your batteries ratings understand what ohms(resistance), currant(amps), Power(watts) and volts are and how they effect your vape. You aslo MUST know how much you can push your batteries and build so as not to inadvertently remove your fingers, jus-sayin’.

      Here are a few tips:
      Ohms is how much resistance your coils put against the energy traveling through your coils, this creates heat, the main ingredient for vaping.
      Amps is how readily your battery will discharge its stored energy, your voltage and resistance directly influence the amperage of your build (higher volts = higher amps, higher ohms = lower amps (V/R)).
      Watts is the power output of the device to reach a specified voltage based on the resistance of your build its primarily associated with regulated mods; however wattage is very present in mechanical mods you just cant change them, they very based on the voltage and ohms of your build.
      And finally, Voltage is the temperature of your vape, with a mechanical mod its based solely on the voltage of the battery you’re using, with a variable voltage/variable wattage device however you can fine tune your voltage to achieve the perfect temperature for you. I will disclaim that different coil types will also change vape temp.

      Happy vaping and BE SAFE!

      Reply
  70. Would using a Samsung 25R 20Amp 2500mH be ok with a 1 or 1.5ohm coil? Whats the lowest i could go with that battery without possibilty of it failing?
    Can i use the same coil with a purple efest 18350 700mah 10.5A?

    Reply
  71. its ok to use .. a effest red and vtc to dual .. ?? i mean .. itsk to use..not same amp.. for example i use dual box mod.. 1 is effest red.. example 25. amp.. and vtc 35 amp..what is the tendency.. to use this. they have a tendency to explode?

    Reply
  72. Quick question. I recently got a dual 18650 box mod and placed one of the batterys (VTC4) in the opposite direction by accident. I fired the button and noticed the mod started heating up rapidly so I panicked and took out the batteries. They were so hot I could even touch them for a good 10-15 minutes. Am I better off disposing of them and getting new ones?

    Reply
  73. Will it be okay if i use a Efest IMR 18650 2500mAh 35A Battery with dual 28 gauge parallel coils? If not any suggestions. Im new to the vape community btw :3

    Reply
  74. I am running imren 18650 3.7v 2500mah. I just got the nitecore intellicharger i2. Just curious if these two are safely compatible?

    Reply
  75. Hello, I have a trustfire 18650 battery and a single coil build, I was wondering what my ohms should be at. Thankyou

    Reply
  76. I’m using ipv 2 at 65 watts on a .3 ohm coil with either lg he2 or Sammy 25r’s or a Panasonic ncr18650pf are these safe batteries?

    Reply
  77. Hey im runing nemesis high q clone with a purple 2100 efest 30A. Im about to buy a driper so what ohm i should get to be safe ?

    Reply
  78. So this means I should be safe using my 0.5ohm kanger subtank with a AW IMR 18650 3.7v 2000mAh battery right? Because if I did my calculations right that would mean the actual discharge rate would be 12.3 out of a max discharge rate of 20. Please let me know as soon as possible. Thanks

    Reply
  79. If u cause a short circuit can u mess up your drip tank?

    Reply
  80. Hi please can u email me and let me know what gauge wire is best for big clouds and a sweet tasting vape I have a kanger sub tank plus on a knight mod clone and using a rba my battery is a efest 3100 mah imr 18650 3.7v li-mn 20a so what gauge wire should I use and how many raps thanks looking forward to receiving your email

    Reply
  81. I’m pretty new to the mech mod game… So here goes…. I have a Sony VTC4 Max Discharge 30A, Nominal Voltage 3.7V, and Fully Charged Voltage of 4.2V. If I throw this battery in a mech mod and pair it with my Aspire Atlantis which has a .5 OHM coil…. with doing the math by using 4.2V divided by .5 OHM coming out to 8.4. I should be safe correct? (This is also taking in the subtracted .2 for the OHM variation which would come out to 14)

    Reply
    • As for the batteries that would be safe for sure; make sure though that if your mechanical mod is a hybrid mod (no positive pin, battery directly contacts the atomizer) that your Atlantis’s positive pin does not “spring” too far so that the battery makes contact with the top of the mod. this would result in your batter venting, and being permanently damaged or destroyed.

      Reply
  82. hello, i use a device that runs on 3.7V 2900mAh… could i run it on a different type of battery, like 3.7V 4200 mAh?? Thanks for the answer…

    Reply
    • You should be able to so long as you’re aware of the amps of your new batteries against the draw of your builds; generally, higher mAh means lower amps so WATCH OUT FOR THAT! also its good to know if your batteries are input series or parallel.

      Reply
  83. hello
    I just got an Eleaf istick 50w sub ohm and using stillare v2 and ive made two coils one on each side with 5 wraps and measured the amount of omhs and I got 1.1 and the vape is not good does that mean I have to lower my resistance and one thing if you can clear up is ,the more wraps the more resistance =more safer right ?

    Reply
    • You need to build higher, at that build you wont even get 2.5 volts. You need 4-6v to have a good vape IMO. Try a 0.4 or 0.5 build at 40-50w and love that.

      Reply
  84. Hi I got a question I just got a mechanical mod with nimbus rda I got a 40 amp battery running it. The battery is called imren 3.7 volts 2500mah. What should my coil be at I was running a .32 and the vapor was getting hot now taste nasty. I have juice on it. Whats a safe ohm for my battery.

    Reply
  85. Hi, I have a Panzer Mod, using a Atlantis V1 with a 0.5ohm coil. I use a 3000 mah battery and also a 1500 mah. Am I in the safe zone? Will learn how this ohm laws work.
    Thanks!

    Reply
  86. Hi, I’m using a Panzer mod with 18650 3000Mah bateries. My tank is a Atlantis V1 using 0.5ohm coils. Am I in the safe zone?

    Reply
  87. So would it be safe to use a subohm tank with .6 ohms of reasistance with dual parrallel unregulated box mod with two18650 1600mAh batteries based on your example in the article?

    Reply
  88. So, how does having multiple batteries and/ or multiple coils affect this equation? For instance; if I had two 18350 1200ma batteries with a .3ohm single coil. What if it was a dual coil; each @ .5? Does the equation change at all? Not trying to confuse anyone, just curious.

    Reply
  89. Pretty sure you’ve answered my question already just wanted to make sure so nothing bad happens. I have been using an eFest 18650 2500mAh 35A battery with a Atlantis Sub tank….my calculations seem to be ok, and I’m under the discharge limit 35A…..just a bit scared when using the sub tanks. Thanks in advance!!

    Reply
  90. I am using the Innokin iTaste 4 1000Ah vv.vw battery and trying to rebuild my atomizer on the Kanger Tech Uniting single coil bottom, top fill juice. I make perfectly looking coils using the coil wrapping calculator but they just don’t seem to work, can you tell me what I might be doing wrong. My multimeter always says way more than my target ohms (target 1.5 ohm resistance with either 30 or 28 gauge Kanthal and I end up with 3. something or sometimes 4. something. Once in awhile I get the resistance I want and I test fire the coil and it works one or two times and then my battery won’t fire it anymore.

    Reply
  91. Would a .6ohm coil be safe with a sony vtc4?

    Reply
  92. I just purchased LG HE4 20a 18650 Li ion 2500mah batteries. Going to be using on all my mech mods. I typically build .2 coils. What’s the safest build range to use with these batteries to ensure no issues??? Thanks guys! ( just got into mech from regulated box mods)

    Reply
  93. I just got a mech mod from a friend, running a .2 ohm dual coil build with a UltraFire BRC 18650 5000mAh 3.7V Li-ion battery is this safe? I haven’t had any issues so far. If .2 ohm is safe, how much lower could I go?

    Reply
  94. Firrs and foremost I’d like to thank the OP and all of the other helpful and knowledgable people for this wonderful and important thread. I saw so many questions about the specific effects and differences of multiple battery series/parallel configurations. I knew what I was taught but I didn’t have any way to show any back up to my claims. So I’ve searched and found an electronics and battery chemistry guru laying the science down on video. I have the link to his YouTube video here. Thank you all for sparking this important conversation.

    http://youtu.be/nxESn_SGFGA

    Reply
  95. Hello I just bought my first mech mod and didn’t have the money to get the rda I wanted. I have a couple Sony VTC 4 batteries and wanted to know if I could put a Smok trophy v2 tank on top and vape that?

    Reply
  96. I recently got a Aspire Atlantis V2 for my EHPRO Kryptonite mechanical mod, but the old 18650 battery I used for my old tank wasn’t really safe to use with the Atlantis. I ordered an Efest 3500 mah 32A/64A 26650 battery. When I use it with my 0.3 ohm Atlantis V2 coils, the entire mod and tank starts to heat up after a few puffs. It said to get a battery with atleast 40A if I wanted to use 0.3 coils, so I got a 60A just to be on the safe side. Did I get a battery that is too powerful?

    Reply
  97. Hi I am new to vaping, I have a ipv3 Li I run at around 80 – 100 watts, I am using samsung INR18650-25R batteries (pairs), what is the lowest ohm (just for my knowledge) that I can build on these batteries safely? I just did my first quad coil build with 24g 8 wraps and it is at about .24 ohms and seems to run fine and the box doesn’t heat up at all. Just wanted to know the threshold of safety so I don’t go over it while experimenting with building coils.
    Thanks

    Reply
  98. Hello! I am so glad I found this article. I’ve been vapimg for 2 years now and started from the bottom up. I am now taking an interest in building coils!

    I have revty bought a Snow Wolf 200w Variable Temp. With kanthal wire, would I be able to build a coil around 0.09 ohms while using a EFESST 35a battery.

    My question is, what is the lowest build I can make while using the 35a (are there any other batteries that have greater amps then efest?), while keeping in mind that I can go up to 150 or 200w?
    I’m using a Holy Grail RDA, btw.

    I want big clouds with good flavor.

    If you would advise me on this, I would very much greatly appreciate it!!

    Reply
  99. I have 8.66 ohms and 3.6 volts is it safe?

    Reply
  100. Hi,

    I am also new to this and wanted to post a potential set and see if it would be a safe build from others that have more experience at this than I do. Thanks for the help!

    Istick 100W Box Mod and the Ijust 2 Atomizer ( Dual Vertical Coils at 0.3 Ohms)

    LG HG2 Battery’s (x2 in parallel):

    Specifications:

    Tyical Capacity: 3000mAh
    Nominal Voltage: 3.6V
    Cut Off Voltage: 2.5V
    Continuous Maximum Charge Current: 4A
    Continuous Maximum Discharge Current: 20A constant current, 35A pulse current load

    (Info obtained from Vapenw.com, just incase)

    Reply
  101. I have samsung 25r batteries rated to 20A I am told. I am running (.3 ohm) and my mod is getting warm to the touch when chain vaping, atty is piping hot so I believe it’s radiating through the stainless is this safe? Also I was told I could go to (.21) ohm at 20A at 4.2 volts safely any opinions on this?

    Reply
  102. guyes how much of an amp boost do you get running dual 18650 battery’s in a regulated mod? i got two 20 amp continuous discharge batters cant find anywhere about how much if any it boosts the amp. thank you :)

    Reply
  103. Is my .17 ohm duel coil build safe for IMR 18650 2500mAh 3.7v battery?

    Reply
  104. Just to make sure. If I get a Sony VTC4 18650 2100mAh with Maximum Rated Discharging Current of 30A I could build as low as 0.4 and be safe ?

    Reply
  105. I just got a SMPL mech mod. I’d like to be able to safely vape at the lowest resistance possible (0.2 is the lowest I would go). Should I go with a Efest V2 35A or a Samsung 25R?
    Thanks!

    Reply
  106. I want to try out a 26650 mexh mod a single battery tube.
    I would like to know what the most recommended battery would be. What tank would go best with a cartel clone or a hommade 26650 mech. (With said battery) and what ohm to run at for complete safety, and a nice bordering on warm vape.
    I know its a lot of questions.. But I don’t wanna blow my face off.
    I’m looking for flavor and cloud comparable to my herakles at 65-85 watts. And would like to know how long a single battery would last.

    Reply
  107. Hi there. Could you explain how (if any difference) that you would calculate the ohms law for dual Samsung 25rs in parralel and series please. I have a parralel mod (incubus) and have an understanding of coil building but would like clarification on how to factor in the differences in power and amps available in dual set ups

    Reply
  108. Hi I’m using the LG HG2s and the Samsung 25rs, is it safe with a 0.2 coil I’m using on my super tank? Also whays the max what’s I can go to thanks!

    Reply
  109. This comment will get buried but maybe someone will see it.. I realize that this was made a long time ago but you should update this list. DO NOT use a battery unless it is made by Sony, LG or Samsung. If you are having to read this please do not get a mechanical/unregulated mod.. At this time you can get very affordable high wattage regulated mods with, such as the Joyetech Cuboid (150 watt mod + temp control), priced at under $40.

    Reply
  110. Great article even better comments and reply I have learnt a lot Thanks 😤

    Reply
  111. I’m using a sigelei fuchai 200W (not sure if the batteries are in parallel or series) and two VTC 4 batteries. What’s the lowest safe resistance my batteries can handle? Thanks

    Reply
  112. Can I swap out a 3.7v 700mah battery with a 3.7v 1000mah battery and if so can I use the same charger to charge both batteries? Cheers

    Reply
  113. Based on the volts/ohms chart above.. I get it that I shouldn’t go under 1.2 ohms resistance no matter what the voltage was?!

    Reply

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