CoilCalc Spreadsheet

[svg1234]

Forgive the "double post", but I posted this in the newbie section and have received very little response - which surprised me. Hopefully the members who read this area of the forum will have more use for it.

I created this excel spreadsheet. It allows you to "what if" coil building and to quickly see what the ohms would be given a certain gauge, mandrel size, device (legs length), and number of wraps.

http://www.e-cigarette-forum.com/forum/new-members-forum/544896-my-coilcalc-spreadsheet.html

If you do not have excel, you can simply upload it to OneDrive to view/use it.

 

[classwife]

Moved to Rebuildable Atomizer Systems - Coil Builds from the Modding Forum

 

[penstyle]

Can you save this in an older MS Office format? Cannot use in Open Office.
Thanks.

 

[svg1234]

Can you save this in an older MS Office format? Cannot use in Open Office.
Thanks.

It was saved in Excel 2007! Old enough! lol.

I tried to save it in OO format too, but there are features which aren't compatible (like the data validation drop-down boxes), so the sheet just won't work properly. I had used OO for many years (being an Arch linux guy), but presently I have NO office s/w of any kind on my main box. Just a waste of space. Don't need it. I normally use google docs or microsoft's web for docs and sheets. Which is why I created this sheet in an XP VM - i.e. Excel.

You can upload it to OneDrive to take a look or use it. Any microsoft account (hotmail, outlook.com, etc) should allow you to do so. Sorry, nothing else I can do.

 

[DejayRezme]

Why not simply quote the link to the spreadsheet in this thread and put it up on google docs? Then nobody needs to download anything
I downloaded it and opened in open office, declined to update external references (potential privacy issue) and got lots of errors. Would still love to see the spread sheet though!

This might be cool for a website too. I'd like to have a calculator to also include things like surface area, surface temperature or required ampere to heat the coil. And heat capacity / self heating could be approximated too to calculate how quick a coil heats up.

 

[Backlash]

It was saved in Excel 2007! Old enough! lol.

I tried to save it in OO format too, but there are features which aren't compatible (like the data validation drop-down boxes), so the sheet just won't work properly. I had used OO for many years (being an Arch linux guy), but presently I have NO office s/w of any kind on my main box. Just a waste of space. Don't need it. I normally use google docs or microsoft's web for docs and sheets. Which is why I created this sheet in an XP VM - i.e. Excel.

You can upload it to OneDrive to take a look or use it. Any microsoft account (hotmail, outlook.com, etc) should allow you to do so. Sorry, nothing else I can do.

it's the MS proprietary xlsx format that doesn't work well on anything outside MS bloatware products.

Why not simply quote the link to the spreadsheet in this thread and put it up on google docs? Then nobody needs to download anything

2nd this.
do not have, nor will I create, any MS account for any reason.
(Sorry, MS and Google are worthless money grubbing lying companies that I will not deal with )

 

[AndriaD]

it's the MS proprietary xlsx format that doesn't work well on anything outside MS bloatware products.

do not have, nor will I create, any MS account for any reason.

Amen brother!!

I can't open it either; I have Office 2003 and that is quite recent enough for XP Pro. I will not open an MS acct, I don't need all the spam they throw. if it's not xls format, it might as well be greek.

Andria

 

[svg1234]

Why not simply quote the link to the spreadsheet in this thread and put it up on google docs? Then nobody needs to download anything
I downloaded it and opened in open office, declined to update external references (potential privacy issue) and got lots of errors. Would still love to see the spread sheet though!

This might be cool for a website too. I'd like to have a calculator to also include things like surface area, surface temperature or required ampere to heat the coil. And heat capacity / self heating could be approximated too to calculate how quick a coil heats up.

lol. I tried to do exactly that before I even wrote the first post about it. Google completely puked. Far worse than OO. I originally began creating it with google sheets, but because there are a number of bugs and the features are limited, I ended up using excel on my xp vm. I normally would have had OO installed on my arch, but the last time I installed it I didn't bother with OO (to keep my system's size down, for backups). I just don't need an office app clogging up my system any longer. So I normally use google, but in this case, it wasn't good enough. Say what you want about msft, but their office s/w is vastly superior to anything google has done so far.

Trust me. You guys aren't telling me anything I don't already know. heheh. I hear ya. If I have some time, I guess I can install a linux distro with OO on virtualbox (with the vdi on a different drive - i.e. no main system bloat) and convert it. It's actually a VERY simple (but smart) sheet. But it uses a couple of things that - as it turns out - aren't done well by the others.

For the time being, if you want to view/use the sheet, there are a number of ways to do it. Not difficult. The easiest is to just upload it to OneDrive.

 

[svg1234]

OK. I was messing around with a few live linux rescue distros, so I downloaded and installed Ubunutu (God help me) to my usb stick because I knew it had Libre Office. I did the best I could to convert the workbook. Although it is incredibly simple, there are some things that excel does in a matter of seconds that OO simply cannot emulate without writing code (which I was too lazy to do). Mind you, nothing critical to the main function of the spreadsheet, but it's uglier and doesn't work quite the same way. Things like dynamic ranges, validation, styles, etc. For example, the drop-down boxes have a long list of blanks because I had to fix the table ranges to the maximum range (because they don't expand properly), i.e. just fill in the blank cells. The data tables are on separate sheets now. If you insert rows in the data table sheets I'm pretty sure you'll break the functions on the main sheet. lol.

Off-topic rant...

I had not used OO Calc in a few years. Was surprised to see how little it has changed from years ago and how far behind even Excel 2007 it is in so many ways. Again, say what you will of Microsoft (I really do hate their o/s's and use them only when absolutely forced to) - but when it comes to most of their office applications, nobody else comes close. Also, Ubuntu is the most pathetic POS I have ever seen. I can't get over how ridiculous it is. I'd say they went after the grandparent demographic - but that would be an insult to grandparents. I used Ubuntu years ago, it was fine back then, but when they started making major changes in the wrong direction (Unity, gnome 3 shell, etc), I switched to Arch and have never looked back. LOVE arch. There are many good linux distros to choose from, but Ubuntu would now be my LAST choice. Tonight was the first time I've looked since I made the move away, figuring that things must have gotten better. Wrong. Far worse. Under the hood, it's fine. Debian. I have Ubuntu server image on my test tier on Amazon's EC2 (just wanted to see what it was about). Absent all the nonsense layered on top, it's ok (though a lot of the s/w versions are very old). I wonder what gnome is looking like now? I'll have to check it out. I use Openbox. No DE. Such a pleasure. OK. /rant.


Hope the conversion was worth it! Enjoy.

p.s. I had to zip it - can't upload .ods files.

View attachment CoilCalc4ods.zip

 

[PaulBHC]

I tried to like Ubuntu but gave up when Win 8 was a $40 upgrade to XP. But I use Libre Office at home because I never owned any MS office.

I'll give this a try. Thanks for sharing.

 

[PaulBHC]

Ok looks good.

If I want to add a device, do I take a coil out of the device and measure the leg length from the bottom of the coils to the tip or the top of the curve or ?

 

[DejayRezme]

Thanks a lot SVG1234, big kudos for your effort I'll have to dig deeper into this, but looks good.

One thing I've found in a german forum thread is a spreadsheet (google drive link) that simply calculates the heat flux, the heat emission of the surface area of the wire. It's in german but you simply take watts and divide by surface area. Would be measured in mW/mm² and it might give a good clue to how well a coil performs (just a clue of course. The OP said between 300-400 mW/mm² is his sweet spot, but might be lower actually). Ideally you would only take the heat emission of the coil itself into account, not the legs.

Ultimately you'd like to know "If I wrap 20 wraps of 8 gauge Kanthal A1 with 1.8 Ohms, will it vape?" (hehe). Oh that reminds me, the ultimate tool would have info on the size of the coil also. Will it fit?

For modeling micro coils you could reduce the surface area depending on how close wraps are. If they are touching (adhesive contact micro coil) you would reduce the actual surface area by 50%, and boost the heat flux by 200% (compared to a loose coil). I'm not sure anymore why and how this would be good X) But this might explain why they perform similar to sub ohm vaping.

 

[svg1234]

Ok looks good.

If I want to add a device, do I take a coil out of the device and measure the leg length from the bottom of the coils to the tip or the top of the curve or ?

No need to measure. Use the 2nd and/or 3rd areas of the main sheet. There are a few ways to do it. Here's one: on the device that you want to determine the total leg length, use the 2nd section and work it backwards. For example, if you know the ohms for a particular coil on that device is 2.1 (from your battery or ohms reader), that that coil has 7 wraps, 32g, made on a 5/64" drill bit - just enter that data in section 2 and start at 0 for the legs length. Continue increasing the legs length a small amount until the calculated ohms equals the KNOWN ohms. Follow? That works perfectly.

Or, if you don't know exactly what was used to make the coil, use section 3 first. As long as you know what the real ohms is and the gauge of wire you used - it'll tell you what the total length of the wire is. Once you know that, then use section 2 to work it backwards. There are only certain combinations of the variables that will arrive at the true ohms of the coil.

What the sheet is really good for is to let you know what the range of possibilities are for a given target ohms on a given device. So let's say you know you need to land between 1.8 and 2.2, you just set that as your lower and upper target. Enter the rest of the data, and the combinations that are within your range will be highlighted in the matrix. What begins as seemingly many possibilities, actually ends up showing you that there aren't that many. I originally had only 32g, so I ordered 30g and 28g (before finishing the development of the sheet). But once I finished and plugged in my device info, etc., I realized that there's no way I can use 28g on the devices I have - with the battery that I have! Why? Because the resistance is too low that you can't fit enough wraps to get into the target ohms range. The sheet shows you the coil WIDTH too. e.g. On rebuilding PT2 heads, the cup is pretty narrow, so you can't go too wide. With more capable batteries (power range) and a WIDER device (which most experienced vapers have) - you have far more possibilities.

 

[svg1234]

Thanks a lot SVG1234, big kudos for your effort I'll have to dig deeper into this, but looks good.

One thing I've found in a german forum thread is a spreadsheet (google drive link) that simply calculates the heat flux, the heat emission of the surface area of the wire. It's in german but you simply take watts and divide by surface area. Would be measured in mW/mm² and it might give a good clue to how well a coil performs (just a clue of course. The OP said between 300-400 mW/mm² is his sweet spot, but might be lower actually). Ideally you would only take the heat emission of the coil itself into account, not the legs.

Ultimately you'd like to know "If I wrap 20 wraps of 8 gauge Kanthal A1 with 1.8 Ohms, will it vape?" (hehe). Oh that reminds me, the ultimate tool would have info on the size of the coil also. Will it fit?

For modeling micro coils you could reduce the surface area depending on how close wraps are. If they are touching (adhesive contact micro coil) you would reduce the actual surface area by 50%, and boost the heat flux by 200% (compared to a loose coil). I'm not sure anymore why and how this would be good X) But this might explain why they perform similar to sub ohm vaping.

The sheet DOES calculate coil width! Take a closer look.

As for heat emission, I'm sure I could add it, but probably won't. I spent too much time on that sheet as it is. But also, those heat figures really won't tell you if it'll vape ok or not. Aside from all the other variables, the coil itself - how it is built - is critical. The spacing, the contact, the legs, the type of wick used, the contact of the wick to the coils, etc. I've built a bunch of coils that all had the same SPECS - but a few were fantastic while others were not good at all. I was surprised at how much of a difference there can be between supposedly identical coils. There is an "art" side to coil building in addition to the science. It's like acoustic guitars. They might build 100 to the exact same specs, but go and play a few, and there will be quite a variation in tone, playability, etc.

 

[PaulBHC]

Thank you so much for this. I use Libre office on W8.1 so don't think you needed to do a Ubuntu install for Libre.

Use the 2nd and/or 3rd areas of the main sheet.

Dooh! I didn't scroll down and didn't know this was there.

I'm new to rebuilding and learning the hard way lol. I have a multimeter and would come up with some number then assemble a coil for a clearo or tank and get a different number on my MVP. Plus I'm older than dirt and lose count of the wraps and then can't see well enough to count them after. Old age ain't for wimps.

I have some 30 and 32 A1 and will try a few mandrels and wraps, measure Ω and write it down. Then assemble and write that down. Repeat enough times to get a consistent number. I share that here for you or others to add to their sheets.

 

[svg1234]

Thank you so much for this. I use Libre office on W8.1 so don't think you needed to do a Ubuntu install for Libre.



Dooh! I didn't scroll down and didn't know this was there.

I'm new to rebuilding and learning the hard way lol. I have a multimeter and would come up with some number then assemble a coil for a clearo or tank and get a different number on my MVP. Plus I'm older than dirt and lose count of the wraps and then can't see well enough to count them after. Old age ain't for wimps.

I have some 30 and 32 A1 and will try a few mandrels and wraps, measure Ω and write it down. Then assemble and write that down. Repeat enough times to get a consistent number. I share that here for you or others to add to their sheets.

Didn't have to INSTALL Ubuntu. I just downloaded the iso and live booted it from a USB stick. Was a good solution to this problem.

Don't use a multimeter for your coils. Just doesn't work well. Also, you never know how much leg you're going to cut off (or leave on the other side of the posts) after you put it into the device. Your MVP should be fine. My battery (itaste vv/vw v3) has a built in reader which is accurate enough. The contact level of the device to the battery also can change the ohms a little bit. (Tighter = more ohms). But nothing beats a dedicated ohm reader that you see the "pros" using.

As far as counting the wraps - yeah, I hear ya! I'm only 51, but my eyes suck, and I've got that near-sighted and far-sighted thing going on (everything is too close or too far). I use two things for this problem: a small halogen desk lamp to give intense light when I need it AND a magnifying glass attached to one of those devices I bought long ago for soldering. I don't know what it's called. It's a little guy w/ a base and "claws" and a magnifying glass. You can find it at any electronics store where they have components, solder, wires, etc. I rarely need the magnifying glass, but the intense light is a must for me. You could also get one of those lamps w/ a magnifying glass - the ones that have arms that bend - that I've seen at Staples and other retailers. I don't like the lamps on those (not halogen) and they are quite large and intrusive but it might be perfect for you.

Here's a trick: I count the REFLECTION of the light off of the coil - not the wraps. I don't focus on the coil wraps or I lose my place. Just focus on the the row of LIGHT bouncing off each wrap. Count the light. It's easier for the eye/brain to focus on. Sometimes I'll use a safety pin to gently run across each wrap as I count. heheh.

 

[PaulBHC]

I have one of those thingys and heard it called a fisherman's friend because they tie flies with them. Or helping hands. I use it sometimes. Bright sunlight today and just used a 5/64 drill and my fingers. Even for feeding the twine.

Touching the tips of the MM I get .4 Ω. Testing a 7 wrap 30ga A1 gives me 2.4 minus the .4 gives 2.0. I made several of these and mounted them in Aspire BDCs as single coils. They came out 1.9 to 2.2 on the MVP. I have a VV3 as well. I usually screw it loose and tight a few times with readings in between. Yeah it changes a bit and I think the device rounds up and down.

Your coilcalc says I should need 8 wraps for 2Ω but that was too high around 2.2 to 2.6. Do I have a number somewhere too high or too low?

 

[PaulBHC]

I went to lightningvapes and their 30ga A1 is 8.36 Ω per foot, divided by 12 is .06966 compared to your 0.7255
I made a line for 30 K A1 and put in the ohms per inch and inches diameter but no metric. Select the new line and the second section says N/A for projected ohms. Do I have to have mm as well?

 

[svg1234]

I went to lightningvapes and their 30ga A1 is 8.36 Ω per foot, divided by 12 is .06966 compared to your 0.7255
I made a line for 30 K A1 and put in the ohms per inch and inches diameter but no metric. Select the new line and the second section says N/A for projected ohms. Do I have to have mm as well?

Hmmm...that's very interesting because I copied the data directly from a lightning vapes page! lol. Take a look.
http://http://www.lightningvapes.com/faq/

I'd certainly like to know which is right! All of my 32g coils matched up perfectly with what the sheet projected, but I had a 28g that was a bit lower in reality than what the sheet projected. Keep in mind that no matter the mandrel diameter, there are differences in the TIGHTNESS of the wraps (the spacing doesn't make a difference). If you wind tightly, which I do (because I pull the legs to make the contact closer, you actually use less wire than if you wind with less pressure. That little difference per wrap can make a small - but significant - difference in the ohms.

The metric and imperial that you see in the sheet are there because the design changed a number of times and they are more of a leftover than anything else. Originally, I had section 2 only (no matrix) w/ two separate columns to input two separate coils - giving the user a choice (based on the mandrel being in metric or imperial). The metric figures in section 2 are NOT converted from the imperial - they are calculated off of the metric data in the table. SO there will be a small difference in that section between the two (due to formula/spreadsheet rounding and the rounding of the conversion data). However, the main matrix only needed one set of data, so it relies on just the imperial. Regardless, you can change any of the data in the tables, so if you have more accurate figures just edit the cells. But don't insert or delete rows in the OO version! The ranges are preset. In teh Excel sheet, the ranges dynamically expand.

 

[PaulBHC]

Interesting that lightningvapes chart shows one number but the order page shows the 8.36 per foot which equals .06966
This company, vapowire also show the 8.36 per foot for 30ga
Vape Knowledge - Vapowire

I deleted the line that I added and changed your 30ga to .06966 and it all comes up with 1.79Ω

Oh well, must be something I do.

Thanks anyway.