Testing the resistance of the entire mod

[Scottes]

In another thread, someone mentioned how a mod or PV can affect performance because of the materials used - copper vs aluminum, for instance. And the amount of it, since this also affects resistance. This makes sense for the mods that use the PV body as part of the electrical path - which is the majority of the commercial big-battery mods.

But everything I've seen so far has been anecdotal and thus simply theoretical. Nobody has ever applied any type of measurements to back up the claim that any particular PV gives the best performance because of the materials and design.

So this got me to thinking of testing all of my devices. I have a dozen different big-battery commercial PVs, and it makes sense for one person with use one multi-meter to use one method to test them.

But I'm not sure of what this method should be.


And I'm hoping that this will spark a conversation around this subject. Does the PV design & material really affect the performancer? And if so, how much does it matter?


As to the method...

My thought was to get a solid copper rod the same size as the unit's battery and measure its resistance. Pop that into a PV, remove the atomizer and place multi-meter leads on the atomizer connector - one on the center post and one on the threads. When the switch is activated, this will measure the resistance of the unit including the copper rod. Once the resistance of the copper rod was subtracted, the final number would be the total resistance of the PV itself.

Sound right?


To test all my PVs, I'd need copper bars to replace 4 or 5 different batteries. And copper bars aren't easy to get ahold of (though I actually think I have a big brass billet that I could use). Any other, easier methods come to mind?

 

[olderthandirt]

Hey scottes
I read those same threads and it got me wondering as well. Nothing to add other than I'll be watching responses on this one!

 

[Archer74]

you just need to complete the circuit right? how about getting a decent size rod and rolling some padding around it to approximate the diameter of the battery?

how bout copper tubes with end cap?

 

[Scottes]

you just need to complete the circuit right? how about getting a decent size rod and rolling some padding around it to approximate the diameter of the battery?

As long as the ends of the rod itself touch the correct points, that should work. So I just need 1 rod, no bigger than 10mm (smallest batt diameter) and then wrap masking tape around each end to get it centered inside the tube.

Sounds perfect. Thanks Archer!

 

[Dorian_Gray]

See your local TruValue hardware store. They all carry copper, stainless and other metal rods and threaded rods of all diameters.

 

[Richie G]

Sound right?


To test all my PVs, I'd need copper bars to replace 4 or 5 different batteries. And copper bars aren't easy to get ahold of (though I actually think I have a big brass billet that I could use). Any other, easier methods come to mind?

I think the most accurate way would be to use "dummies". These are used to make up space within the battery tube where two of the same battery types are used but when you don't want to put two batteries in series.

Like this one for a CR123a ---
CR123A Size Dummy Cell - 0 Voltage for Flashlight spacer DUMMY-CR123A

It might make sense to do a resistance reading on the dummies too and figure that into the equation.

 

[NickJuice]

I'm VERY interested in how this turns out...the problem to really see a difference your going to need a VERY sensitive Meter

 

[RenaissancePuffer]

Would something like this method work, except instead of testing the voltage while device is powered on, test the resistance while it is not powered?

http://www.e-cigarette-forum.com/fo...-device-under-load-prodigy-other-devices.html

I would think you should be able to identify the resistance of the entire device from battery connector to atomizer.

 

[Scottes]

I'm VERY interested in how this turns out...the problem to really see a difference your going to need a VERY sensitive Meter

Really? Bummer. I have a cheapo. It goes down to 1/100 of an Ohm, but I don't know if I trust the accuracy. I was planning on taking 3 readings per device to (hopefully/somewhat) overcome this inaccuracy.

I might be able to borrow a nice Fluke from work though.

Would something like this method work, except instead of testing the voltage while device is powered on, test the resistance while it is not powered?

My issue with that would be the differences in the atomizers. My PVs are mainly a mix of 801 and 510, so I can't use 1 atomizer consistently through all the tests, thus I'd prefer to eliminate it. As long as it's not needed, and I'm pretty sure it's not.

 

[Shreck]

This would definitely be interesting to see what you come up with. Wont different rod lengths have different resistances, thus skewing your true final numbers?
And how much resistance difference throughout the PVs body, compared to the next one, is actually going to make a noticeable difference in the vape quality??
Seems to be many many variables, but all we really have to go on now, is people saying, "Boy this sure vapes better than that"

Good luck with this, and will be watching...

 

[youtubecommercial]

This would definitely be interesting, I will be watching the thread to see how it progresses

 

[jeffakamax]

A fluke will not work either. My hand-held will do 1/1000. It's fairly accurate but it jumps. If you put it on a scope, then you have something.

I've tested Alum, Brass, Copper, Stainless, and Titanium. Last night in fact. I was going to post results but I'm not stirring the pot.

 

[Richie G]

A fluke will not work either. My hand-held will do 1/1000. It's fairly accurate but it jumps. If you put it on a scope, then you have something.

I've tested Alum, Brass, Copper, Stainless, and Titanium. Last night in fact. I was going to post results but I'm not stirring the pot.

Awww, c'mon Jeff. 'Tis just an open theoretical discussion. Whad-ja find, whad-ja find, whad-ja find? <g>

 

[Scottes]

Shreck - I plan on testing the resistance of each rod and subtracting from each measurement to ensure that I get the resistance of the PV as accurately as possible.

Jeff - Re: Fluke: I'll see what happens. This may all be a bust on the first test - but I've got some other test comparisons I want to do. Resistance was just one of them.

Jeff - Post what you know! Heck yes! You're not going to stir my pot.

 

[Some Guy]

Chart with resistivity of metals
Electrical conductivity - Wikipedia, the free encyclopedia

Sure seems to me you would need something fairly sensitive to tell the difference between aluminum and copper etc. . Especially in only 3-5 inches of material.

But I am interested also.

 

[Shreck]

A fluke will not work either. My hand-held will do 1/1000. It's fairly accurate but it jumps. If you put it on a scope, then you have something.

I've tested Alum, Brass, Copper, Stainless, and Titanium. Last night in fact. I was going to post results but I'm not stirring the pot.

I know what you mean by not stirring the pot, and I find that you are a real gentleman and scholar. ( maybe you dont like being called that) LOL.
But it would be nice to see what you came up with. I have seen charts showing the resistance of various metals, but we want real life results. The proof is in the pudding, as they say!
Although is the reistance of metals, once again, going to make any real noticeable difference in the quality of vape that a PV produces.
Thats the question I have!
Its not like we have miles of metal here to reduce the quality of the current, is there? Maybe I am wrong, thats why I would like to see soemthing as well..
Either way, In my opinion, just from use, I believe that Aluminum produces a good enough flow of current to light my attys sufficiently...

 

[Shreck]

* At 20º Celsius, based on copper as 100.
** Per degree C at 20º C.
Note: The conductivity of various metals is subject to variation according to processing and alloy composition.

Aluminum 59
Brass 28
Cadmium 19
Chromium 55
Cobalt 16.3
Constantin 3.24
Copper:
Hard drawn 89.5
Annealed 100
Gold 65
Iron:
Pure 17.7
Cast 2-12
Wrought 11.4
Lead 7
Manganin 3.7
Mercury 1.66
Molybdenum 33.2
Nichrome 1.45
Nickel 12-16
Nickel silver 5.3(18%)
Phosphor bronze 36
Platinum 15
Silver 106
Steel 3-15
Tin 13
Titanium 5
Tungsten 28.9
Zinc 28.2

Taken from http://www.myhrsb.ca/Functions/Program/Static/Curriculum/eng/science/9/SupplementaryPages/MetalsElectConductivity.htm

 

[535cheetah]

ya i had made a post in there ... not understanding how less resistance made any vaping tool better, yes i can see if it uses the body itself or parts of it, to carry the current to the atty.... resistance would be futile lol.
but other then that it shouldnt matter.... but im no electrical genius... wouldnt be the first time ive been wrong.

 

[mnealtx]

The only way the body construction is going to make a difference is if there is an appreciable difference in resistance. Given the lengths of material used for the different mods, I'd expect the spring material making the negative connection to make more of a difference than anything else.

 

[ZeroNullity]

It is true that all materials have different resistance to the flow of electricity, water, copper, gold, brass, plastic, etc. It will depend on the material used & the application to weather or not it will greatly affect your project results. Copper will out perform steel.. 3%-15% vs. 100% Compared to pure copper, aluminum is not as conductive as copper(slightly more then half). Silver is actually more conductive then copper at a rating of 106% to 100%(not by much). Gold is less then copper, but greater then aluminum. Brass is better then steel but half as much as aluminum, etc. Titanium, Steel, Platinum, Nickel, Lead, Cobalt, Wrought Iron are the weakest. Of course given they are all preforming at the same temperature.