Become a Patron!

Confused about ohms and batteries

WillyTheMLGPro

Member For 2 Years
Member For 1 Year
I currently own a Bonza rda with a ijoy captain pd270 and I've been looking at getting a mechanical tube mod to match it. I'm current have it running 2 alien coils from Cloud Revolutions that run at 0.11 ohms. I've been looking to match it with a Broadside tube mod but when I've done the ohm's law calculations, my coils will need 38 amps and I'm not aware of any 18650 capable of that. And when i watch the Vaping Bogan's video on his Danesa 2 video, he's using the same coils on a single battery so I'm not sure whats going on. Am I doing my calculations wrong or am I missing something.
My planned setup is a Bonza rda with dual alien coils at 0.11 ohms in a Broadside mod with a Sony VTC5A.
 

Carambrda

Platinum Contributor
ECF Refugee
Member For 5 Years
You are missing multiple things. First off, you need to also account for the voltage sag of the battery, which, if using a single VTC5A, at the ohms you are suggesting, is going to be a little more than half a volt. Secondly, you need to also account for the resistance of the tube mod itself, as well as the fact the CDR of a battery is assuming the amps will be invariable, which, even if the button gets stuck on the mech, they aren't. So in the example you gave there's no chance in hell you'll be drawing those 38 amps from the VTC5A. (On the broadside it will be much closer to 33 amps.)

That said, for new vapers as a starting point it is generally recommended to stay at or below the CDR (25 amps for the VTC5A). Going above that is not called recklessness if you know what you are doing, as technically there are no hard numbers, but you said you are new to mechs, and, if you're going to go above the CDR, then that implies you're going to have to be sure to know what you're doing─and accept the added risk you're going to get from that. Personally, I, vape on a dual coil alien build at .11 ohms with a single VTC5A all the time. The reason I feel comfortable with the heightened risk is because first and foremost I understand it's all about duty cycles. I.e., not holding the fire button down too long, and giving the battery enough time to recover between pulls. This can be learned by pulling the battery out frequently and feeling how warm it gets. Above 45°C (113°F) is where the battery starts aging faster than normal. More importantly, I always make perfectly sure the mod can't start firing (or continue to fire) inadvertently in any way. Last but not least, I also know how to avoid causing a dead short, so I'm not going to be in the newspaper and I'm not going to blow my face off. Instead, I might perhaps vent a battery one day, but I also know that this can still happen nevertheless even if I decide to vape at 20 or 15 or 10 or 5 amps (or even at 0 amps, for that matter).
 

gbalkam

Gold Contributor
Member For 4 Years
ECF Refugee
Reddit Exile
I currently own a Bonza rda with a ijoy captain pd270 and I've been looking at getting a mechanical tube mod to match it. I'm current have it running 2 alien coils from Cloud Revolutions that run at 0.11 ohms. I've been looking to match it with a Broadside tube mod but when I've done the ohm's law calculations, my coils will need 38 amps and I'm not aware of any 18650 capable of that. And when i watch the Vaping Bogan's video on his Danesa 2 video, he's using the same coils on a single battery so I'm not sure whats going on. Am I doing my calculations wrong or am I missing something.
My planned setup is a Bonza rda with dual alien coils at 0.11 ohms in a Broadside mod with a Sony VTC5A.
First thing remember.. a regulated mod is not a mechanical mod. Regulated mods handle watts differently and have numerous fail safes to make them less dangerous. NO mod is "SAFE". You do what you can to make them as safe as possible. Luckily, the VTC5A has a 25A Continuous Discharge Rate (the amount of current you can draw without overheating and damaging the battery. You can use ohms law calculator to stay at or below the cells CDR.

http://www.steam-engine.org/ohm.html

you can use this coil building tool to preplan your coils and even virtually fire them by looking at the heat flux mw/mm2 Vaping should be 280 to 400 the higher the number the warmer the vape.

http://www.steam-engine.org/coil.html?p=roundmulti&s=dp&r=0.18&hf=300&str=2&awg=26&id=2.26
Please, look this build over very well and use ohms law before you consider using it. I don't like showing coil builds for mech users. YOU have to decide if you want to vape it, so you should look it over. I used a build for dual core claptons, dual coil. I know that build will be below your 25A CDR or I wouldn't have linked it. (triple checked)

The build in that link runs at or below 25A. Keep in mind, this will not be the same for every cell. A 20A cell for example... this build would be a bit high.

Now the first thing you need to know, is that a mechanical mod has only 1 variable that you can adjust, and adjusting that variable changes a lot of factors. The first factor is that the resistance of your coil totally controls the Amps drawn from your battery. Use the ohms law calculator to demonstrate using various resistances. I'm not really sure what Carambrda meant by the cell will not reach above 33A, since Mooch has stress tested them up to 70A. (way way way above CDR and well out of the recommended 25A CDR of the battery) **Stress testing is using a cell well above it's CDR to determine how fast the cell heats up, how much damage is done to the cell, and is done in controlled conditions. Mooch is a PROFESSIONAL. He does testing for various companies not vape related, but also free of charge for the vaping community. In other words, just because Mooch tested these cells in his workshop with his equipment, doesn't mean YOU should try this at home.**

Personally, I would keep your resistance at or above 0.18 until you become comfortable. The cell will allow you to go lower, even 0.15 wouldnt be to bad. As Carambrda said, they vape the cell at 0.11 ohm, which is still within limits, but work your way down to that while you get used to mechanical mods. Remember.. the lower your resistance, the higher the amp draw and the less time you have if something goes wrong (such as a stuck fire button) Also keep in mind not all atomizers are usable with mech mods, mainly if the center pin does not protrude far enough to contact the +cap on battery without letting the negative threading touch as well. Make sure your tube mod has adequate ventilation as well. A venting battery can blow up a poorly vented mod.

Quite frankly, you will probably prefer the vape you get from your existing, regulated mod, and the mech will end up sitting in a box. Really the only reason to have a mechanical mod now, is for mech class cloud competitions, which are advanced builds. You would be better off spending your money on some nice shiny new atomizers. Tsunami, TwistedMesses, MutationX V4 are my fav RDA and I have an Ijoy RDTA combo which is pretty neat. Basically, Mechanical mods in general are not for new to intermediate vapers and require advanced knowledge to maximize safe usage. I am trying to stress this a fair bit, because the question you asked in your post is information you should already know without having to ask when using an advanced vaping mod. Basically... if you were going to put a gun in your mouth, would you trust my word that there was no bullet in it....or would you make damn good and sure there wasn't, for yourself? Don't take any offense to this, none is intended. This is stuff I had to be told, then research and now I'm passing it on.
 
Last edited:

Carambrda

Platinum Contributor
ECF Refugee
Member For 5 Years
For reasons that are completely obvious, when I said "in the example you gave" I was referring to vaping at .11 ohms on the Broadside with a single VTC5A battery in it. After you subtract the voltage sag from the resting voltage as well as you take into account the resistance of the Broadside mod itself, you will see that the amp draw in this same example will be closer to 33 amps, not 38 amps. To which I'll add that, when I bought my first mech, I started vaping on it with a .11 ohms dual coil alien build and a single VTC5A immediately the same moment I bought this mech. I'm only saying this because it is perfectly possible for some people to know exactly what they are doing, even before they bought their first mech. I'm living proof of it in fact. To stay at or above .18 on a single VTC5A is what I would recommend to a headless chicken. But then again... headless chickens should probably stay away from mechs as far as they possibly can, anyway in the first place, and, I have zero reason to assume that you are a headless chicken, so hopefully that explains why I haven't tried to treat you like a headless chicken. :D
 

HondaDavidson

Gold Contributor
Member For 4 Years
So do you have a good Volt ohm meter?
Have you ever heard of ohms law?
Does Steam-engine.org tell you you are safe?

AS far as I'm concerned. ... the build you describe is unsafe.. for an 18xxx unprotected mod and Any mechanical using less than 2 batteries in parallel. .. 3 or 4 would be best.

Sent from my SCH-I605 using Tapatalk
 

Mattp169

Platinum Contributor
Vape Media
Member For 5 Years
ok so basically\you need to decide for yourself what is safe and WHY

start here

mooch does know more then most so you can take what he says as factual.

can you do what you want safely-sure
can doing what you suggest cause problems - yup it can, dangerous problems

could you blow your face off - yup but by doing something else regardless of the battery and the coil

you need to do much more battery and mech research to understand the risks involved
 

gbalkam

Gold Contributor
Member For 4 Years
ECF Refugee
Reddit Exile
ok so basically\you need to decide for yourself what is safe and WHY

start here

mooch does know more then most so you can take what he says as factual.

can you do what you want safely-sure
can doing what you suggest cause problems - yup it can, dangerous problems

could you blow your face off - yup but by doing something else regardless of the battery and the coil

you need to do much more battery and mech research to understand the risks involved
Totally agree. I did 6 months research before buying my first mech. At the time I was with ECF so Mooch was available for questions and to point me to various tables and graphs. Nothing is "safe" so learn everything you can to reduce the risks.
 

VU Sponsors

Top