Why is it important to check ohm on coils

[antony73]

I've been using a Vision Spinner / MVP2 and Protanks for some time, and am getting ready to build my own coils and start dripping. I'm thinking of buying a basic non-brand Atomizer to test with, to see whether or not it is something I want to invest more in.

I have done much research on this forum on building coils and studied some videos, but one things that always comes up is the importance of checking the coil's ohm. I usually enjoy 2.5ohm on 3.3/6v for the e-liquid that I use, but what is the real issue of checking the ohm, apart from finding the sweet spot. Are there some safety issues involved?

A picture of the Atomizer I'm considering.

 

[Jscheiben]

From what I've read(getting into coil building today) is that most regulated devices wont fire a coil under a certain resistance. That and if you try to draw too many amps for a battery it can cause some safety issues. Seeing that you have the MVP 2.0 that shouldn't be an issue as it can measure the resistance for you(same one i'm using). And I am by no means the deciding authority on this stuff so everyone chime in.

 

[Susan~S]

Battery Thermal Runaway.

It's not a problem in a regulated battery, but it's a real concern in unregulated devices. Here's what it looks like with li-ion batteries in a laptop and how hard it is to stop it.

For anyone rebuilding coils and using them on an unregulated device should spend some time learning about ohms law, volts/watts and battery safety. Check out Pbusardo and his video on Sub Ohm Safety. The safety section starts around 16:00 minutes into the video. And check the links he has listed under this video for some more valuable information.

 

[TheGrimmReefer]

Sound advice ^

 

[Vaslovik]

For what you are using checking the resistance in your atty isn't an issue, your Protank coils are sold in various resistances, and you don't need to check them, just screw them in and vape. It becomes important to check your ohms when you are winding the coils yourself, such as when you are setting up an RBA and winding kanthal coils yourself. You want to make sure you don't have a hard short first, and second that you have wound your coil for the resistance target you had in mind.

 

[BostonVape]

Battery Thermal Runaway.

It's not a problem in a regulated battery, but it's a real concern in unregulated devices. Here's what it looks like with li-ion batteries in a laptop and how hard it is to stop it.

For anyone rebuilding coils and using them on an unregulated device should spend some time learning about ohms law, volts/watts and battery safety. Check out Pbusardo and his video on Sub Ohm Safety. The safety section starts around 16:00 minutes into the video. And check the links he has listed under this video for some more valuable information.

Well at the same time.. this is regarding SUB OHMS... OP said he usually vapes at 2.5 ohms so unless he is planning on building below 1 ohms its tough to relate to alot of that video

 

[CreepyLady]

For what you are using checking the resistance in your atty isn't an issue, your Protank coils are sold in various resistances, and you don't need to check them, just screw them in and vape. It becomes important to check your ohms when you are winding the coils yourself, such as when you are setting up an RBA and winding kanthal coils yourself. You want to make sure you don't have a hard short first, and second that you have wound your coil for the resistance target you had in mind.

This ^^^

10 char

 

[D. Waterhouse]

Well at the same time.. this is regarding SUB OHMS... OP said he usually vapes at 2.5 ohms so unless he is planning on building below 1 ohms its tough to relate to alot of that video

Unless his build has a short, then the video is completely relevant. Test your coils before you fire them Every Time.

EDIT: Every new build, not every time you fire it. Safety first but even I think testing before every puff is a bit much.

 

[Completely Average]

Well at the same time.. this is regarding SUB OHMS... OP said he usually vapes at 2.5 ohms so unless he is planning on building below 1 ohms its tough to relate to alot of that video

Part of the reason you test the ohms of a coil is to make sure you do not have a short. If you have a short then the ohms is 0 regardless of how you build the coil. If that happens it's like placing a wire from one battery terminal to the other with nothing else in between. It's a runaway short circuit.

 

[antony73]

Sorry... but I need to ask... what is a short?

I am guessing that a short is when the two ends or parts beyond the wraps touch each other. Correct? Similar to re-wiring an electrical socket and doing it SO badly that some copper from one wire is touching the other. (I have never done this by the way. Just an example).

And I test the coil by screwing it into my MVP2 and pressing both buttons. Right?

(Maybe I'm over reacting, but I'm somewhat nervous of getting this wrong. I've seen the photos of exploding batteries. I really don't want this happening in my closed fist and so close to my face).

 

[BigCatDaddy]

You'll see why when you get that RDA and start building coils. You can watch videos till the cows come home but until you start doing it yourself, no way will you know how hard it can be to get that just-right coil or dual coil setup. Plus, it's handy as a base for putting the base of your RDA on while you are trying to get those tiny wires into those tiny slots or holes. Since you are using Protanks, rebuild some of those little guys, so worth the time and effort. You will be amazed at what a hand built coil and a bit of cotton wick will do for them. Yummy vape and flavor!!!!

 

[Gonzi]

When building a new coil, you check the resistance to make sure that there is no short as stated above, that it's at your desired resistance level and to make sure that it's securely fastened to the posts, if there is a bad connection somewhere, your resistance will jump up and down.

Then you test fire it to make sure that your coils are properly spaced and fireing evenly.

 

[BostonVape]

Part of the reason you test the ohms of a coil is to make sure you do not have a short. If you have a short then the ohms is 0 regardless of how you build the coil. If that happens it's like placing a wire from one battery terminal to the other with nothing else in between. It's a runaway short circuit.

I understand.. thats why I said its tough to relate to a lot of the video, not the ENTIRE thing lol

 

[Bunnykiller]

technically a short is a condition in which current is allowed to flow thru a conductor and allows enough current to flow to damage the circuit or power supply...

the coil in your atty at say 2 ohms may be just fine and operate quite well, but use the same coil with 100 volts, it would be a short...

 

[antony73]

This is a little off topic, but I read that when wrapping the coils, the wraps cannot touch, that there must be spaces between wraps. I also read the complete opposite. I'd would assume that wraps touching is not a big issue, as long as they're not too tight. Please correct me if I'm wrong.

And big thank you for your replies. All very interesting stuff. Beats smoking any day of the week

 

[Bunnykiller]

Sorry... but I need to ask... what is a short?

I am guessing that a short is when the two ends or parts beyond the wraps touch each other. Correct? Similar to re-wiring an electrical socket and doing it SO badly that some copper from one wire is touching the other. (I have never done this by the way. Just an example).

And I test the coil by screwing it into my MVP2 and pressing both buttons. Right?

(Maybe I'm over reacting, but I'm somewhat nervous of getting this wrong. I've seen the photos of exploding batteries. I really don't want this happening in my closed fist and so close to my face).

most VV/VW units sense a short/low ohm situation and shut down, protecting the circuit board and battery

 

[Bunnykiller]

This is a little off topic, but I read that when wrapping the coils, the wraps cannot touch, that there must be spaces between wraps. I also read the complete opposite. I'd would assume that wraps touching is not a big issue, as long as they're not too tight. Please correct me if I'm wrong.

And big thank you for your replies. All very interesting stuff. Beats smoking any day of the week

wraps can touch each other, once the wire is heated to a glowing state, it developes an oxidation layer on the wire, thus "insulating" itself from the adjacent wrap. The process of "glowing" the coil aides in making the coil better.

 

[Gonzi]

This is a little off topic, but I read that when wrapping the coils, the wraps cannot touch, that there must be spaces between wraps. I also read the complete opposite. I'd would assume that wraps touching is not a big issue, as long as they're not too tight. Please correct me if I'm wrong.

And big thank you for your replies. All very interesting stuff. Beats smoking any day of the week

You either want the wraps evenly spaced not touching, or a compressed coil with all the wraps touching. It's either all or nothing. If you have the coil build sloppy, you'll have hot spots, meaning that places that are wrapped tighter or wraps closer together will heat up quicker causing a hot spot, wich can and will cause burnt taste and harsh vape.

If coils are compressed and touching, you need to heat it up to properly set the coil and oxidize the wire to aid in even heat up from the center of the coil out for best vaporization and smoothness of vape.

 

[Neunerball]

This is a little off topic, but I read that when wrapping the coils, the wraps cannot touch, that there must be spaces between wraps. I also read the complete opposite. I'd would assume that wraps touching is not a big issue, as long as they're not too tight. Please correct me if I'm wrong.

And big thank you for your replies. All very interesting stuff. Beats smoking any day of the week

You either want the wraps evenly spaced not touching, or a compressed coil with all the wraps touching. It's either all or nothing. If you have the coil build sloppy, you'll have hot spots, meaning that places that are wrapped tighter or wraps closer together will heat up quicker causing a hot spot, wich can and will cause burnt taste and harsh vape.

If coils are compressed and touching, you need to heat it up to properly set the coil and oxidize the wire to aid in even heat up from the center of the coil out for best vaporization and smoothness of vape.

An example would be, to take one of your used coils from your Protank 2 and take it appart. You'll see a Micro coil. I'm replacing my coils on my Protank 2s, utilizing a 32 gauge Kanthal A1 doing 10-11 wraps arround a 18 gauge blunt syringe needle. That gives me a 2.0 - 2.5 Ohm coil.
A tightly wrapped coil produces more heat than a loosely wrapped coil, as you might have figured out by reading Gonzi's comment.

 

[Maestro]

Your MVP won't let you fire if you have a short. From a safety standpoint, checking your resistance isn't necessary. It's more important for people who have a device that won't automatically prevent them from exceeding the amperage limit on their batteries.