rebuilding a viva nova

Status
Not open for further replies.

trishdadish

Senior Member
ECF Veteran
Verified Member
Jan 6, 2013
183
153
Victoria, British Columbia
I've been playing around, rebuilding my attomizer? Is that even the word for the coil that heats up? Anyways, my local store set me up with 33g kanthal wire, and I've been trying differing amounts Iof loops to achieve different strengths,(I guess ohms?). The problem is my creations don't give me the same vape. I feel it's too weak.would a thicker wire produce more smoke? I made one up by doubling (twisting the wire like a rope, and when I drip tested it it looked like it worked great! But I haven't used it yet, I'm scared I'll kill my battery.......I do have a volt meter, just haven't used it because I'm having a hard time understanding the relationship between ohms , volts, and finding that sweet spot without killing your battery
 

JazzyTech

Super Member
ECF Veteran
Nov 16, 2012
812
508
California
First, I'd suggest you try google for youtube vids on rebuilding the Vivi Nova. Second as for your double wire coil: Set your voltmeter to "ohms" have a look online for what the symbol looks like :) You connect one lead from the voltmeter to one end of the coil, and the other lead to the other end of the coil. color doesn't matter in this case. I'm not certain what the lowest ohm is that your battery can take. I'd recommend nothing below 1.8 ohms. If it's around 2 ohms or a bit higher, that's fine.

I've heard of people doiubling up their wire to make better coils. Yes, it will run down your battery a bit quicker, but not much faster than most larger gauge coils would. As for vapor, I have no idea if it's better. You will have to judge that. I'm sure someone more knowledgable will chime in with their opinion. Good luck!
 

JazzyTech

Super Member
ECF Veteran
Nov 16, 2012
812
508
California
There's no straight answer when making your own coil. The diameter of the coils and the number of them all affect the resistance outcome. Most people test every coil they make to insure it is withiin tolerances. I know that 1.8 or higher is considered safe for most all PVs. I would think a coil between 1.8-2.2 ohms will be quite a hot vape if your twist is set to higher voltage :)
 

dam718

Ultra Member
ECF Veteran
Verified Member
Dec 30, 2012
1,797
2,268
Hawaii
I'll address a couple of your questions...

Yes, the part you're rebuilding with the wire coil is called the atomizer.

It should be wrapped around a wick. Are you replacing the wick when you are rewinding a new coil with the kanthal wire?

Is that what you're referring to when you say you're twisting it together like a rope is the wicking material? Or are you twisting the actual metal wire that you make the coil out of?

Answering that will help me out a bit...

And for a very quick layman lesson on how that resistance wire (Kanthal) is working...

33AWG is referring to the size of the wire. The numbers relate to the size of the wire in an inverse fashion, meaning that the higher the number, the smaller the wire. 33AWG (American Wire Gauge) is pretty tiny, 34 is about as small as you would want to go.

Wire gauge can be loosely related to a water pipe... A big huge pipe will allow water to flow very freely, this means it has very little resistance, which in electrical terms in measured in Ohms. A little tiny pipe will create a lot more back pressure to push the same amount of water through at the same rate of flow, this little tiny pipe has very high resistance. So, using that analogy, a wire with a lower gauge has a lower resistance than a wire with a higher gauge. Because 33AWG Is pretty small, it has pretty high resistance. Depending on how many times you are wrapping your coil, you could be ending up with a coil with an overall resistance somewhere around 4 Ohms. With 33AWG I probably wouldn't wrap more than 4 times, 5 at the most. Now this is a guess, but 5 should get you around 2.8-3.2 Ohms.

I don't know what type of device you are using, so I am going to assume you are using a device with fixed voltage. Most of these fixed voltage devices have a voltage of 3.7V

At this point, the relationship of voltage, resistance, current, and power all come together. These factors of electricity are all calculated using formulas based on Ohm's Law and Joule's Law. Joule's Law states that Power (Measured in Watts) is equal to voltage squared divided by resistance. I like using this formula over the standard Ohm's Law calculations because it makes it unnecessary for us to determine current. For the purpose of this conversation, we don't NEED to know how much current is being pushed.

What we DO want to know, is how much heat your device is going to create with your custom wrapped coils!

That's where power comes in. Power, or Watts, is directly related to how much heat you will create.

So, if we know the resistance of your coil, and we know how many volts your device is set to, we can easily determine how many watts your coil is burning at using Joule's Law.

A couple of quick examples, all using the assumption that your device is fixed at 3.7V: 3.7 x 3.7 = 13.69, so we will use 13.69 as our Voltage Squared variable.

First, with a custom coil of 4 Ohms: 13.69 / 4 = 3.4225 Watts
and second with a coil of 3 Ohms: 13.69 / 3 = 4.5633 Watts

Now, this is VERY general, but I have heard that most folks like to vape at somewhere between 6 and 9 watts...

What you can see above is that neither a 4 Ohm OR a 3 Ohm coil are going to get us into that range. Both are still going to burn relatively cold at 3.7V. So, in order to get into that 6-9W zone, we need to reduce the resistance of our coil. Using a variant of the formula we used above, we can find out a range of resistance values that will work for us. That formula is resistance = voltage squared divided by power.

So we still use 13.69 (Voltage Squared) and now we plug in our high and low range wattage values that we'd like to reach.

13.69 / 6 = 2.2817 Ohms
13.69 / 9 = 1.5211 Ohms

So, to achieve a burn of 6 watts, we need a resistance of ~2.3 Ohms, and for 9 watts we need a resistance of ~1.5 Ohms

So, if your 33AWG wire, which has a higher resistance, is burning too cool, we need to use a bigger wire. So step it up to 32AWG. 5 wraps of 32AWG kanthal will give you a resistance of ~2 Ohms. This is right in your range! 4 wraps will be a little it less resistance which will burn hotter, and 6 wraps will be a little more resistance which will run cooler.

Hopefully all that makes sense. I can certainly answer any questions you might have! I apologize for the lengthy pot, but I thought it would help you understand the correlations on exactly how Voltage, Power, and Resistance are all working together to achieve that vapor quality you're looking for :) I hope it helped! LoL, probably made it worse!
 

dam718

Ultra Member
ECF Veteran
Verified Member
Dec 30, 2012
1,797
2,268
Hawaii
I forgot :)

A really useful tool for figuring all this out

Ohm's Law Calculator

Plug in any 2 values, and it spits out the other 2 values for you using the formulas described above.

I see you said you have an eGo Twist, this is good news :)

I'd try to wrap a coil around 2 Ohms. With your 33AWG wire, that may be difficult. Try a coil with 4 wraps and see what that gets you using your volt meter to check the resistance.

Oh, and do not twist the metal wire together... This would, effectively, drop your resistance in half, which could be dangerous. It would be better to just get 32AWG wire. I haven't seen 31AWG, and from what I hear 30AWG is a bit tough to wrap cleanly. 32 has been perfect for me.
 

trishdadish

Senior Member
ECF Veteran
Verified Member
Jan 6, 2013
183
153
Victoria, British Columbia
:)dam718
.......n you know alot. too answer the first ?, I'm using glass fiber wick, usually about 3 because they're pretty thin. I checked my supplier and I was wrong about the wire, it says Nichrome with a rating of 980 ohms. iwas using 2.4 heads, before and was quite happy..but they're out and it will be a while before they get more.what type of store would carry a heavier gauge and longer lasting wire than the one I have? what metals are safe? what should I be asking for? and btw, I found your post awesome, I was able too figure out I like running just under 8 watts.thank you so much for taking the time!!!
 
Last edited:

dam718

Ultra Member
ECF Veteran
Verified Member
Dec 30, 2012
1,797
2,268
Hawaii
Nichrome is good as well... Hmm... 980 Ohm rating sounds a bit odd... Does it say anywhere what the AWG value is?

I don't know what they mean by 980 Ohm though... That may mean that the whole spool is 980 Ohm, or 980 Ohm for a specific length, like 980 Ohm per 100ft. I'll have to do some research on that and get back to ya with what I find out.
 

dam718

Ultra Member
ECF Veteran
Verified Member
Dec 30, 2012
1,797
2,268
Hawaii
Are you getting the Nichrome online? If so, can you post a link where you got it? Just need some more information about the wire you're using. The other resistance wire you could use is Kanthal A-1. I got my Kanthal from RTD Vapor, I think it was around $13 for 100ft. I don't think I'll be running out... EVER... LoL

Short of posting a link to where you got it, would you be able to post a picture of the label, or provide any additional tech specs about the wire?
 
Status
Not open for further replies.

Users who are viewing this thread