Confusion...Ohms, Volts, Watts oh my!

[IrishUpstart]

I will preface with a statement: The more I read, the more I get confused.

I am desperately trying to figure out my new toy (itaste mvp) and whenever I think I understand, I read one little thing, and my world of understanding gets dropkicked into oblivion. Quick note to mods: While I will be referring to VV, this is more of a quest for general knowledge, so I opted to post here. Sorry if this is still the wrong place.

Anyway...

My understanding is this. Using a figure I found someplace, the safe voltage rating for a given resistance is about ohm + 1.8, give or take a little bit depending on personal preference. With that said (if accurate), a good/safe voltage for a 2.0 ohm cart/clear single coil would be 3.8v. Thus, a standard battery...let's say the Volt X2....would be good to go as it is 3.7v. But, some of those prefilled carts from the big cig-a-like companies are around 2.7 ohm (rough average) making the ideal voltage around 4.5 which they are not capable of outputting. Now, I get that they can fire them, but the coils don't get very hot and results in a cooler vape. All of this makes sense for the most part.

Now I am going to tackle dual coil carts/clearos. The mvp came with a couple clearos that were rated at 2.093 (2.1 for simplicity) ohms or something goofy like that. My understanding is that the 2 coils are run in parallel which means that each coil is actually 4.2 ohms. That being said (and about where my brain caves in) the ideal voltage over-all would be 3.9v but each coil would be 6v. I read somewhere that 2.0 ohm dual coil set up's are really only intended for 5v+ devices but yet they were packaged with a device that tops out at 5v.

tl;dr version....I want to order new stuff for my vv device, but the math makes really no sense to me and I don't know what it is that I should be buying.

 

[jfango]

Sorry but I'm not familiar with the device you have but let me make things real simple for you. If it's a VV device, just put whatever tank gadget you happen to have on top of it, and make sure you gots the juice in it. Now turn the adjustment to a fairly low setting, and give it a try. If you don't seem to be getting much from it there, turn it up a notch or two. Keep doing this until you are getting a decent hit from it. If you go too far, it will taste burnt, so just turn it down a bit and try again. That's about as complicated as it needs to be, don't bother with all the math, just let the mathmaticians worry about all that. LOL! Happy Vaping!

 

[Nore]

 

[Ryedan]

Sorry but I'm not familiar with the device you have but let me make things real simple for you. If it's a VV device, just put whatever tank gadget you happen to have on top of it, and make sure you gots the juice in it. Now turn the adjustment to a fairly low setting, and give it a try. If you don't seem to be getting much from it there, turn it up a notch or two. Keep doing this until you are getting a decent hit from it. If you go too far, it will taste burnt, so just turn it down a bit and try again. That's about as complicated as it needs to be, don't bother with all the math, just let the mathematicians worry about all that. LOL! Happy Vaping!

Very well said jfango and absolutely correct. If this system does not work for you, your battery might not have the power to drive your juice delivery device effectively or something else is wrong.

 

[nahoku]

I don't know what kind of device this mvp is, but anytime you're running a dual coil cart, all you have do is figure the total power based on the values you know and then take 1/2 of that power to figure out what each coil is dissipating. If we use some of your numbers... 3.9v with a 2.1 ohm cart should give you 7.24 watts total. Thus each coil is heating up to 7.24/2 = 3.62 watts. Quite low and your vape will be cool.

However, this is not to say that you'll actually be able to tell that its cool. Most people can, but some don't even know it. Alot of ecig kits, like the Volcano Inferno kit, comes with and is recommended to use 1.5 ohm dual coil carts. Going with the same calculations based on a fresh battery (4.2v), each coil would only dissipate 5.88 watts. This too is considered cool to most people, but then beginners can't even tell it is and it's satisfying to them.

Have you tried these 2.1 ohm carts on your device? If so, what do you think about the vape?

 

[Ryedan]

My understanding is this. 1) Using a figure I found someplace, the safe voltage rating for a given resistance is about ohm + 1.8, give or take a little bit depending on personal preference. With that said (if accurate), a good/safe voltage for a 2.0 ohm cart/clear single coil would be 3.8v. Thus, a standard battery...let's say the Volt X2....would be good to go as it is 3.7v. But, some of those prefilled carts from the big cig-a-like companies are around 2.7 ohm (rough average) making the ideal voltage around 4.5 which they are not capable of outputting. Now, I get that they can fire them, but the coils don't get very hot and results in a cooler vape. All of this makes sense for the most part.

Now I am going to tackle 2) dual coil carts/clearos. The mvp came with a couple clearos that were rated at 2.093 (2.1 for simplicity) ohms or something goofy like that. My understanding is that the 2 coils are run in parallel which means that each coil is actually 4.2 ohms. That being said (and about where my brain caves in) the ideal voltage over-all would be 3.9v but each coil would be 6v. I read somewhere that 2.0 ohm dual coil set up's are really only intended for 5v+ devices but yet they were packaged with a device that tops out at 5v.

tl;dr version....I want to order new stuff for my vv device, but the math makes really no sense to me and I don't know what it is that I should be buying.

1) The average sweet spot voltage for a given resistance is about ohms + 2 (you said + 1.8, no real difference). The rest of what you say in that paragraph makes perfect sense.

2) I suggest you leave the dual coil thing alone for the time being and come back to it if and when you decide that it is where you want to take your vaping. By then you will know enough about it to know what is required to get the most out of it. I assure you, in the meantime you will be missing nothing. Dual coils are not required to get the most from vaping and they can sometimes be quite challenging to make work properly.

Best of luck with it.

 

[jdrewry]

This helped me understand it better...

Taking The Mystery Out Of Variable Wattage - Spinfuel Magazine | Spinfuel Magazine

 

[Katya]

http://www.e-cigarette-forum.com/fo...n-electrical-stuff-i-double-dog-dare-you.html

 

[Rachy_B]

Whomever made that chart gets my respect...in bucket loads! If I had a colour printer, I'd print that!x

 

[DavidOck]

Agree with the above, above. Especially the comments about starting at a low volt setting and working up until you get the vape you like.

I have an MVP, and have been running dual coil cartos in tanks with no problems. It will do fine with whatever you put on it, as long as the coil doesn't need more than a total of 3 amps.

 

[tj99959]

My understanding is that the 2 coils are run in parallel which means that each coil is actually 4.2 ohms. That being said (and about where my brain caves in) the ideal voltage over-all would be 3.9v but each coil would be 6v

Your real life experience with DCC's will be that the "ideal voltage" will be half way between those two ideal voltages (or about 5 volts)
This is kinda like what do you do to a stove to keep water boiling after it has come to a full boil. (turn it down)

What will actually happen is that you will find out what the amp limit of your PV is.

 

[CloudZ]

Here is what I have learned about dual coils, first the hard way then the smart way...

Obviously the first one is buying some dual coil cartos that are not working very well, even with my Spinner maxed out at 4.8 V. Their resistance is 1.5 ohms.

Next I figured out what the problem is using ohms law. At this maximum voltage and on the 1.5 ohm carto, I get 15.36 watts, or 7.68 watts per coil. You'd think this would be close enough... But it is not the whole story. The amp limit on an ego battery is 3 A. To actually hit the voltage I have set the spinner to, I would need 3.2 A. Taking the limit into account, the highest voltage the battery can supply to a 1.5 ohm dual coil is 4.5 volts. This yields a total of 13.5 watts, or 6.75 per coil.

The moral of the story: unless your battery has a higher current limit, skip the dual coils and go for single coils. The bigger VV/VW mods will power dual coils just fine, but an ego-type battery will not.

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[forg1vn]

Here is what I have learned about dual coils, first the hard way then the smart way...

Obviously the first one is buying some dual coil cartos that are not working very well, even with my Spinner maxed out at 4.8 V. Their resistance is 1.5 ohms.

Next I figured out what the problem is using ohms law. At this maximum voltage and on the 1.5 ohm carto, I get 15.36 watts, or 7.68 watts per coil. You'd think this would be close enough... But it is not the whole story. The amp limit on an ego battery is 3 A. To actually hit the voltage I have set the spinner to, I would need 3.2 A. Taking the limit into account, the highest voltage the battery can supply to a 1.5 ohm dual coil is 4.5 volts. This yields a total of 13.5 watts, or 6.75 per coil.

The moral of the story: unless your battery has a higher current limit, skip the dual coils and go for single coils. The bigger VV/VW mods will power dual coils just fine, but an ego-type battery will not.

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does anyone know if the dual coils are in series or parallel? i would imagine building them in series would be rather foolish and the way to go would be in parallel, and if they are in parallel, each leg of the circuit would have its own full voltage same as source, its own wattage instead of dividing by 2?

 

[CloudZ]

does anyone know if the dual coils are in series or parallel? i would imagine building them in series would be rather foolish and the way to go would be in parallel, and if they are in parallel, each leg of the circuit would have its own full voltage same as source, its own wattage instead of dividing by 2?

Parallel. Voltage is the same but the current is divided. You still just take the source voltage divided by the total circuit resistance to get the source current, which has to split in parallel. Current is constant in a series circuit, but voltage drops.


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[niczgreat]

I agree stay away from Dual Coils.
They aren't necessary for the best vape.

The chart above is an excellent recource. It should be noted that the MVP drops around .10-.14 of a Volt under Load at the lower Voltages to as much as .2V under load at the higher.

So if you are vaping at 5V the Mvp under load the MVP will give you a 4.8V Vape
and if you are vaping at 3.7 it'll give you close to a 3.6V

This is verified in a review by Clouds of Vapor and I took my own Voltage Indicator [Meter] and confirmed it.
There is one further variable which is that the Resistance or coils of your Atomizer may have a standard deviation of as much as 1/2 and Ohm for example I have a Boge 2.5 that is registering at 2.8 or 2.9.

A really great device for measuring this is a ohm tester Digital Cartomizer / Atomizer Resistance Tester (Ohm Meter)

The best out there is the elusive ECD Meter from Stoney in Australia, but he can't keep up with demand.

The old fashioned way of raising an lowering according to taste should work well too.
But I'm like you, I like to know

 

[IrishUpstart]

Thank you for all the responses. I appreciate the information.

So basically, I think I will stick with single coil carto/clearos for now until I can fully wrap my brain around all this VV stuff, and continue to use the dual coil clearos that came with it because I do enjoy my straight menthol juice out of them. I believe I will pick up a hand full of carts of varying resistances and use try them out until I find which one works best. I may even try a carto/tank which is something that I have not yet.

Thanks again!

 

[forg1vn]

Parallel. Voltage is the same but the current is divided. You still just take the source voltage divided by the total circuit resistance to get the source current, which has to split in parallel. Current is constant in a series circuit, but voltage drops.


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oh thats right the total current in a parallel circuit is the sum of its legs...my bad

 

[CloudZ]

oh thats right the total current in a parallel circuit is the sum of its legs...my bad

No worries. Electricity is really tough to visualize and I never really got it in school. I am an ME by education but I was forced to learn some of these basic concepts once I started working.


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[forg1vn]

No worries. Electricity is really tough to visualize and I never really got it in school. I am an ME by education but I was forced to learn some of these basic concepts once I started working.


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yah well this really isn't something i should be forgetting considering i have to recert my A8 electrical ASE soon...:/ but normally the answer is short to ground haha...or so it seemed

 

[DavidOck]

Ah, well, we all have those moments. As long as you don't space out on your partner's name, it's all ok