Trying to grasp coil vw basics

[Synphul]

I've been trying to look at various charts to determine appropriate coil builds and wattage settings. So far I'm only confused by it so hopefully someone can help straighten me out.

Many voltage/ohm charts are like this one linked off Phil Busardo's site.
http://25.media.tumblr.com/tumblr_m9dkanCt0I1qc8949o2_1280.png

If I understand that chart, stay out of the red. I built a coil out of 316L ss that reads 1.99 ohms, so at 2 ohms I should go to a 'max' of around 8-9w at 4.2v. When I set my mod to this though I get squat for vapor/flavor. I end up going to 14-15w at 5.46v. Is this dangerous or less than desirable for a dual 18650 mod (parallel, not series)?

I'm not sure if that chart is strictly for mech mods or what. Originally the plan was to shoot for tc but in my rush to throw it together I forgot about the 1.5ohm cutoff for t.c. for my device. Oh well, no biggie I don't mind going with vw for now.

That brings up another issue, I used steam engine's coil calculator. I chose 316L ss/elite from the drop down, round wire, single coil, target resistance of 1.5ohm, inner diameter 4mm, a generous 20mm total leg length (each leg around 10mm long), 10 wraps. Should get me close to 1.5ohm target resistance. I counted my wraps, I have 11 because I was trying to get the leg both facing the same direction so ended up with an extra wrap. Ok so plugging in all the same data and going to 11 wraps I come up with 1.67-1.7ohm resistance. Why is my build coming out to 2ohm?

So far I seem to be way off on the ohm/watts chart, I seem to be a fair amount off compared to steam engines calculator so feel like I'm driving blind. Thanks in advance for any assistance.

 

[HondaDavidson]

Are you using a chart created in the last 1 or 2 years or an old one. Sounds like you are using an old one ment for unregulated mods. Basically the only numbers that are fixed are the safe amp range numbers. With regulated that means... If the mod fires, I'm probably safe. If I like the vape the settings and build are correct. I Otherwise best is what suits youbest. This value may not be the same for every juice, rig or build.

Sent from my SCH-I605 using Tapatalk

 

[Synphul]

I don't know for sure when the charts were made, even the ones I've seen here in the charts section of the forums go to 2014 and show 15w getting close to the edge of 'green/pink' for 2ohm resistance. Though no designation of what green or pink mean, green being safe (I assume).

http://vapingunderground.com/threads/volts-ohm-watts-chart.1595/

It may be for mechanical mods to sort it out since resistance of the coil plays such a huge factor. Using the istick tc100w with the usual low voltage, short circuit, temp protections. I'm no engineer so I don't get voltage bucking or whatever it is that the chips do inside a regulated mod. Using ohm's law, with a coil at 2ohm and setting my mod to 16w in spite of voltage being raised to 5.66v the amperage is hovering around 2.83amp (theoretically, no account taken for battery sag or internal inefficiency). Using a mod with dual 18650's (samsung 25r's with a 20a continuous output rating) in parallel means I'm well within safe?

 

[HondaDavidson]

Yes less than 3 amp draw on 20 amp Batts in parallel is well within the 40 amp limit you are running with. Does the is tick even do 40. I thought it topped out below that. So even more safety.


Sent from my SCH-I605 using Tapatalk

 

[Synphul]

Ok good to know, thanks for the response and helping clear things up!

Honestly I have no idea, I don't see it listed in the specs either online anywhere or in the manual as far as amp limits. It fires up to 75w in single battery mode, up to 100w with dual 18650's (120w with firmware update). It lists temp ranges for tc mode and lists wattage from 1-100w but I know there are some mods that won't do the absolute max wattage based on the resistance of the build. For instance at .1 ohm it may not go all the way to 120w and why it won't go to over 75w in single battery mode.

 

[JERUS]

With a regulated mod you don't really need to worry. Those charts are nothing more than guidelines for people that don't really have an understanding, but they are far from hard and fast rules. Right now I have a 1.3Ω dual coil setup running 40w which is about 7volts, those charts show it as being a terrible idea, however it works great for me. The chips in the regulated mods will take the power of a battery (amps * voltage = watts, so a 20 amp cell is safe at 74watts fully charged easy) and convert it as needed using the buck-boost fancy stuff (gotta admit I don't fully understand that still, but seems it's about pulling some power and storing it to boost what you need when you need it).

Anyways, it's your wicking and the coil and the airflow and all this fun stuff that works together to make what you need. Regulated mods will keep you safe as long as you don't do something stupid like tossing an Efest battery in there, if it says to get a 25amp cell, get something at least at the samsung 25r level or above (those aren't 25amp cells but they perform well when pushed, LG HD2C, VTC4, LG HB series would be your best bet if you're feeling paranoid). But, you're right about regulated mods cutting you off even if you input a higher power level. The Cuboid is the best well known example, it has a 25amp output limit (I wish every mod would label things fully), meaning you put a .15Ω coil on it and the highest you can go is ~94w, even if you set it higher that's all you're going to get. The XCube II works the same way in that it hinders you though not as bad as the Cuboid I don't think. These things of course are built to protect you and I'm not complaining about the fact that they do this, I just wish they would be more open about the limitations they put on so I can knowingly work within them.

Anyways, 15w, you're more than ok, you shouldn't have any problems at all. I have my single battery mods doing more work than that and I have no issues.

 

[Synphul]

Thanks for the reassurance Jerus. I just wanted to be sure and I agree I have no issue with mods that limit output for safety reasons. To me that's a perk but fully outlining these things would be helpful for sure. Not really an issue for me since I don't do any crazy big builds, no dual/quad coils. More of a flavor person and prefer to save where I can so opted for a single coil rta for juice conservation.

I did read through Mooch's battery guides and a number of others opinions on batteries and why I went with samsung 25r's. Didn't want the headache of trying to locate genuine vtc4's or 5's and not using a hard hitting device like a mech in series or anything. Never say never I guess but I don't see myself using anywhere close to 100w, at least not anytime soon. The 25r's seemed a nice balance between amps and mah and was shooting for extended battery life. Just didn't want to be making a stupid mistake not paying attention to it and end up killing my batteries prematurely or anything.

 

[JERUS]

25rs are my favorites, and while I've had no issues at all (I don't go too crazy) I know some other members here have hardshorted them and no booms or bangs, just lots of heat, that's a trusty battery right there. I still have a few of the heftier batteries on hand for when I do go nutso on my mechs, the lower mAH and higher CDR batteries also hit harder for the time they last which is nice (though you'll likely not get that in a regulated).

 

[ozo]

I too am confused by the charts. I just joined here (15mins) looking for similar answers.
I have had no problem using KA1 and simple single/dual builds....for almost 2yrs. I just began my sojourn into claptons and I can't seem to get the right wattage for the ohms to where it even tastes decent, much less the vapor I am used to.
I understand I haven't had/taken time yet to read what is most likely already discussed in length, and I plan to search for it here. I just thought I would get started.
I use Kanger KBOX mini's 50w and 75W and their RBA's, Istick TC 100W's, Avocado 22 & 24 [single and dual coil builds], TF-RDTA's, and others.
I know what my juice tastes like, how my devices normally perform [calculated from steam-engine], then I see Rip and other vids that claptons are superior,
but in my new endeavor with them, not much luck yet.
I am old, obviously missing something, so I humbly came here for help.......
I only use 25R's and HE2's and HE4's, authentic as best as I know.
I will spend time searching on VU long before I start a thread that is surely already in existence.

 

[Synphul]

I too am confused by the charts. I just joined here (15mins) looking for similar answers.
I have had no problem using KA1 and simple single/dual builds....for almost 2yrs. I just began my sojourn into claptons and I can't seem to get the right wattage for the ohms to where it even tastes decent, much less the vapor I am used to.
I understand I haven't had/taken time yet to read what is most likely already discussed in length, and I plan to search for it here. I just thought I would get started.
I use Kanger KBOX mini's 50w and 75W and their RBA's, Istick TC 100W's, Avocado 22 & 24 [single and dual coil builds], TF-RDTA's, and others.
I know what my juice tastes like, how my devices normally perform [calculated from steam-engine], then I see Rip and other vids that claptons are superior,
but in my new endeavor with them, not much luck yet.
I am old, obviously missing something, so I humbly came here for help.......
I only use 25R's and HE2's and HE4's, authentic as best as I know.
I will spend time searching on VU long before I start a thread that is surely already in existence.

As far as I know raymo2u (hopefully I got his name spelled right) is a coil wizard around these forums. From what I understand not all claptons are equal, done right they're supposed to be much better for flavor. I have no idea how to factor clapton resistance since it's usually done with 2 wires of different gauge and the smaller gauge wrapped tightly around it. Resistance would be less than a single wire but I don't know by how much.

 

[HondaDavidson]

Take a look at Steam-engine.org. Play with the calculators and a lot of your build questions will become a bit clearer. Or you will have more..... There even a page that give MOD specific info. http://www.steam-engine.org/modrange.asp There are calculators for building claptons. Theres also aps like Vapetool and a bunch of other I cant remember in the ap stores.

 

[JERUS]

As far as I know raymo2u (hopefully I got his name spelled right) is a coil wizard around these forums. From what I understand not all claptons are equal, done right they're supposed to be much better for flavor. I have no idea how to factor clapton resistance since it's usually done with 2 wires of different gauge and the smaller gauge wrapped tightly around it. Resistance would be less than a single wire but I don't know by how much.

For resistance you just need to calculate the core resistance. The inner diameter of the wrap you adjust for 2X the diameter of the clapton wrap then it's pretty much the same. As always steam-engine won't get things exact as there are imperfections in reality it can't calculate, but it'll get you close. Basically the clapton wrap is so high resistance that almost no current passes through it, so you're essentially just working with the core wire.

If I wanted to calculate a 2X26g/40g fused clapton wrapped around a 3mm post and 8 wraps per coil I'd set steam-engine up like this playing with resistance until I got close to 8 wraps:http://www.steam-engine.org/coil.asp?p=roundmulti&s=dp&r=0.3&str=2&awg=26&id=3.16&ll=10

If I wanted different core wires like maybe 26gSS/26gKA1 wrapped in 40g same setup I'd jump tot he wire wizard. and see a single coil is at .45Ω so my duals would be .225Ω

 

[ozo]

The inner diameter of the wrap you adjust for 2X the diameter of the clapton wrap

Thanks for the info. You lost me on this though ^^^^^^^
I use steam-engine all the time. I don't have any problems with reaching my resistance goals, and I also make some nice clapton wire, usually 32ga over 28ga, and even better since I got the V2 clapton jig. I just can't find the right wattage for my mods, and the 'Mod Range' on steam-engine gets strange sometimes, like a 2.9V 15.3W recommendation.....for a TC 100W and a .38ohm dual Ka1 build. [which obviously hardly fires]
I am persistent, and I will get it (someday), but the sweet spot is hiding from me at the moment.
I see that you use a lot smaller wire for your claptons than I do. Yours are fused, right?

 

[robot zombie]

If you're using any sort of current VW mod, then going by resistance is counter-intuitive. I always say that this obsession with resistance is a relic from the days when VV and unregulated were king. It's not really practical to think this way anymore with VW being so prevalent and people building such a wide range of different coils.

Say you have two builds: a dual 24g and a dual 28g. Both have a resistance of .5 ohms. You wouldn't give the dual 28g nearly as much voltage, as the dual 24g has ~6 times more mass! The power it takes to drive it would fry the 28's, while the power the 28's perform well at wouldn't be nearly enough for the 24's. So as you can see, these power charts aren't all that helpful. They would need to be rediculously comprehensive to be worth using at all.

I say don't bother with these charts. Let your mod worry about things like resistance, voltage and current. That's what it is designed to do. Focus instead on the mass of your coil. That's what determines the wattage. And the wattage is what ultimately determines how much amperage your batteries have to give. That the resistance is within the range the mod accepts and is low enough for your mod to be able to deliver enough wattage is all that matters as far as resistance is concerned.

If, for whatever reason, there is a target wattage that you want to hit, use the heat flux calculator. Specify the wattage you want and start plugging in builds. The calculator will give you a good idea of whether or not the wattage is enough or too much to the power the build to the temperature you want.


Another thing worth mentioning about how VW devices get their power: resistance doesn't matter. Essentially, the device takes the current it needs from the batteries to hit the set wattage before shifting voltage/current around to get that same wattage to the coil, as per ohms law. The actual power section is a semi-discreet circuit that doesn't play by the classic rules of ohm's law.

If you set the mod to 100w and you have two batteries kicking out a total of, let's say 8v, then the mod will always, and I mean ALWAYS pull about 14A from the batteries to power the coil, whether it is a .1 or a .5. The difference will be in how the power is distributed after being generated.

Because of this, all that your resistance determines is the power cap on the mod. You cannot power a high-resistance build to the same wattage levels that you can achieve with a low, sub-ohm build because of the voltage output limitations of two stacked batteries. They can only give about 8v under load, and that's kind of a generous max. Most mods will cap it off at around 7v.

Say you have a .5 build on there. The highest you can go is going to be about 100w, as that requires 7 volts, which again, is towards the top of what the batteries can give. The mod can cut voltage down to current to power lower-resistance builds, but it can't produce more voltage than the batteries can kick out naturally. This all comes back to ohm's law. To hit a given power level with a given resistance, you will always need a certain amount of voltage to sustain the current required. You can't exchange insufficient voltage for current to make up for it. They're interrelated. The push to get enough current through simply isn't there past a certain point.

On the flipside, a .1 only requires around 3v to hit 100w, meaning you can still go much, much higher. Even at 150w, you still have plenty of voltage to play with. The limit there is really just how much current the batteries can give. 200w from batteries kicking 8v is already ~28A. So you hit the opposite barrier.

Basically, VW safety all boils down to wattage, wattage, wattage. Use steam engine's battery drain calculator in VW mode to see examples of what I'm talking about. Make sure you set the battery voltage to 8, as that's what fresh batteries kick out. If you want to see how the mod reacts to low batteries, drop the voltage to 6. If you're running a single-battery mod, drop them down to 4 and 3, respectively. The second box from the right shows what your batteries give at the wattage setting, while the second from the left shows how that power gets distributed through the build.

 

[Synphul]

Thanks robot zombie. Thinking I'd have to figure based on 4.2-3.2v anyway since my mod runs dual batteries in parallel rather than in series.

 

[robot zombie]

Thanks robot zombie. Thinking I'd have to figure based on 4.2-3.2v anyway since my mod runs dual batteries in parallel rather than in series.

Ahh, well that is unusual and you would be correct. But still, it is is only slightly different. Two batteries in parallel just means you have double current tolerance instead of double voltage, so the strain on the individual cells doesn't change much. It's not as power-efficient and it's not an even trade-off, since you're realistically not getting exactly double the current to play with... ...usually a little less, like 10%-25% (or at least, that's generally the assumed margin.) So there is that. But other than that, the figures are interchangeable.

Two batteries at 8v need to give 14A to achieve a working 100w. Two batteries at 4v need to give a combined 28A to achieve 100w, but since they're in parallel, each battery still only gives 14A. Best to assume one battery may have to give more, while the other gives less and lower your wattage margin a bit to compensate, but in practice, there's little difference. You just want to stay a bit more below your batteries' CDR with parallel.

Just out of curiosity, what mod are you using? You don't see too many para reggies anymore.

 

[Synphul]

istick tc100w and running 2x samsung 25r's which should be pretty solid at 20a each. I'm well below that running a single coil at 1.1ohm and 25w. Definitely won't be running any higher anytime soon, have another thread where I was asking others why my wicks seem to be burning at around 30-35w or so. Been staying under, steam engine shows under 9a draw with that setup at 25w factoring 90% efficiency.

I've been seeing where people basically said those charts are more or less for mechs and that not much changes with coil resistance using a regulated mod. That watts is more the determining factor for things like battery life and everything else so long as my overall amps are in check. With burnt taste at around 35w safe to say I won't be anywhere near 50-100w lol.

 

[Lefty]

istick tc100w and running 2x samsung 25r's which should be pretty solid at 20a each. I'm well below that running a single coil at 1.1ohm and 25w. Definitely won't be running any higher anytime soon, have another thread where I was asking others why my wicks seem to be burning at around 30-35w or so. Been staying under, steam engine shows under 9a draw with that setup at 25w factoring 90% efficiency.

I've been seeing where people basically said those charts are more or less for mechs and that not much changes with coil resistance using a regulated mod. That watts is more the determining factor for things like battery life and everything else so long as my overall amps are in check. With burnt taste at around 35w safe to say I won't be anywhere near 50-100w lol.

The coil and wire used to reach a given resistance governs how much wattage it will handle. Use the Coil wrapping section at Steam Engine to see what heat flux you get with various coils and wires at the wattage of your choice to get an idea how much wattage a particular coil can handle before the heat becomes too much.

 

[Synphul]

Thanks Lefty, finally figured out how that bit of steam engine works. Couldn't figure out what wattage to put into the calculator then finally realized it's asking what wattage the mod is set to and changes the flux accordingly. For someone who's not an electrical engineer the site isn't always the most intuitive.

 

[Lefty]

Don't feel bad, when I first started using the site and sometimes still, it felt like playing chopsticks on a Steinway.

 

[robot zombie]

Thanks Lefty, finally figured out how that bit of steam engine works. Couldn't figure out what wattage to put into the calculator then finally realized it's asking what wattage the mod is set to and changes the flux accordingly. For someone who's not an electrical engineer the site isn't always the most intuitive.

Well FWIW, the info to be had from SE is more there to serve as a guideline or maybe put something you already kinda understand into a tangible form. If you don't understand the concepts, then there's only so much the numbers can help you with - though once you do understand something, they can help solidify what you've learned.

I think most people just learn by doing with this sort of stuff. That's mostly what I've done. You eventually find yourself just knowing what to do without thinking about it. And then, when you read about it, it's a eureka moment. If someone tried to explain to me all of the technical stuff that I now intuitively understand back when I was newer to this stuff, it wouldn't have made sense to me at all. The frame of reference would've been missing. It'd just be a bunch of numbers and moon runes.

The experience just has to come first sometimes. You have to be patient. Don't worry so much about what you know, summon up the patience, and do some problem solving with whatever you have to go by.

Real talk, you really don't need to be an electrical engineer to have a working understanding of this stuff. You don't need SE for anything beyond battery safety. The technical, "theoretical" side of things gets pretty out there, but in practice, the devices we use are very simple. It all boils down to a bunch of "If this [result], then that [course of action]. It eventually clicks for most everyone, but not everyone speaks the vernacular or even really understands how/why things work. They just know what works because they've tried it enough times.


The basic rule for figuring out coils and wattage is to first do a build that you think will have the properties that you want in such and such atty system. Then, you start lower than you think you need to until you reach a point where it performs like you want to. If you can't find that point somewhere between "not enough" and "too much" power, then you have either the wrong build (or the right build, but set up wrongly) or the wrong atty and that becomes your next attack point. Rinse and repeat as needed.

I think the worst thing you can do is limit yourself to certain types of builds/atties or give yourself a fixed wattage range. These factors may not wind up sitting where you think you'll like them. Keep an open mind in experimenting and you'll figure a lot of stuff out quickly. Even the stuff that doesn't work teaches you more about what you like and what you need to do to get it.

 

[Synphul]

When it came to the heat flux portion of steam engine, I thought it was like factoring in the % of efficiency for the mod. Like on battery drain they say they start you off with 90% efficiency and it's designed for the user to adjust the % based on their actual mod. So when there was a heat flux wattage I thought it was the same thing. Not knowing and se not explaining it, I was trying to figure out what the heat flux was for ss, like it was a value for a given wire.

Didn't realize it was for the user to plug in the wattage they were running their device at and then it gave the heat flux range to the right of it. That took me a bit to realize which is why I say se isn't always intuitive right off if you're unfamiliar. That's when I realized based on the wire I'm using and at what resistance, my heat flux range was limiting me a bit. A narrow window of wattage options between cool and fiery hot vaping was topping out at 30-35w. Not that I need to go higher, have any desire for a particular resistance or wattage, I just wanted some room to play with the heat for flavor production without going good, good, burnt.

Definitely wanted to get a grasp of battery safety, even though it's a regulated mod I don't like entrusting safety all to electronics like a security blanket. Also looking to make tweaks to get the best flavor I can with my setup until I get other tanks, looking to extend battery life at the same time if possible and so on. I didn't have any fixed range I thought would be best, just didn't have much wiggle room to try out different combos. Felt like I was limited in where I could test it at without cooking everything.

 

[HondaDavidson]

Steam-engine is great even for those that don't really understand electricity. There are even some instruction blogs for SE over on ECF. (might also be available elsewhere)

Even if you never figure out how to use it for building coils. It still is good for checking battery safety.

To understand SE I just entered the data from every build I did or read about on the forum and even the numbers from factory coils.
I pretty much just watch a few numbers on SE the #wraps, the HF the Heat capacity and the surface area. I like to vape in a specific wattage range for battery life and safety purposes. So I adjust my build to run as desired within those parameters.
The trick is getting the HF and HC to offset each other. If the HC is a little higher I might not need as high a HF. But if the HC is too high it take forever to heat and cool and too low never gets hot, regardless the HF. I have learned that if I build a coil with more surface area, The HC goes up and the need for HF is reduced. A 1 ohm coil made with 30awg will have a higher HF than a 1 ohm coil with 28, but the 28 will likely vape hotter because being bigger it has more capacity for transmitting heat. 2 small wires twisted together and having the same resistance per inch and a thicker solid wire , can have almost the same HF and surface areas but do the the different capacities vape totaly different.