Coil resistance change

[Justadude]

Can any of you guys confirm that a resistance in a coil changes when being fired up?

I've build one of many stapled tiger coils and noticed that when fired it the resistance lowers and as I put it on the meter the resistance will raise to a specific number as the coil cools off.

Keep in mind that there are 3 different types of wires in a stapled tiger coil - 36 kanthal wrapped around nichrome 80 ribbon twisted with 24 gauge nichrome. It seemed a lot more stable and didn't fluctuate as much when I had it twisted with 24 kanthal, but when twisting with a 24 nichrome the resistance goes down quite a bit when hot and gradually raises as the coil cools off.

That's a first time I've seen this so that's why I'm asking if any of you have come across this.

 

[astronomicals]

I've build one of many stapled tiger coils

so youve built one variation on wire types? I think thats what you mean. Any time my ohms fluctuate its loose post connections. If that aint it, I have no clue. Good luck.

 

[Treeburner1983]

If I'm not mistaken, nichrome wire changes resistance with temperature, while kanthal doesn't. That's why the temperature control mods use nichrome, so it can measure temperature based on change in resistance.

-Treeburner

 

[Justadude]

If I'm not mistaken, nichrome wire changes resistance with temperature, while kanthal doesn't. That's why the temperature control mods use nichrome, so it can measure temperature based on change in resistance.

-Treeburner

Makes sense. But if I have a build at .144 ohms and I put it on the mod, fire it up then take it off and put it back on the meter and reading .106 and then gradually starts going up to .144 something has to be wrong. It shouldn't jump THAT MUCH. Or am I wrong?

 

[93gc40]

If I'm not mistaken, nichrome wire changes resistance with temperature, while kanthal doesn't. That's why the temperature control mods use nichrome, so it can measure temperature based on change in resistance.

-Treeburner

All wire changes resistance and conductivity with temperature.. Some type do it more or less and faster and slower than others. Even wire of the same type but differing gauge and configuration can react differently.

 

[Justadude]

All wire changes resistance and conductivity with temperature.. Some type do it more or less and faster and slower than others. Even wire of the same type but differing gauge and configuration can react differently.

But half an ohm? Isn't that too big of a difference?

 

[mcclintock]

Wires INCREASE resistance when hot. This has to be some contact resistance change.

 

[Justadude]

Wires INCREASE resistance when hot. This has to be some contact resistance change.

Interesting

Needless to say I tossed both of those coils. Something is obviously wrong.

 

[Justadude]

I'm seriously confused now. I just made two simple coils. Just regular old fashioned coils. The resistance is doing the same thing. Going from really low when hot to what it's supposed to be when cooled off. Anyone got ANY ideas what this could be?

Any feedback would be greatly appreciated. I have no idea what's going on.

 

[Marc411]

Something was making a bad contact dude. It could have been the legs inside your posts, the 510 was lose or the screws just weren't tightened enough on the legs.

 

[Justadude]

I just tried my Hobo and I'm not having this problem. What's wrong with this stupid authentic mutation x v3?

 

[Spencer87]

weird maybe the meter having issues... with the connection to that specific RDA

 

[Justadude]

Something was making a bad contact dude. It could have been the legs inside your posts, the 510 was lose or the screws just weren't tightened enough on the legs.

Idk dude. Screws all the way down and very secure. 510 also tight. Just checked it before I even fired it up the first time tonight. Legs inside the posts were all the way through. Battery and mod doesn't get hot.

When cooled off its sitting stable at .144 ohms. I fire it up for for 3 seconds and drops to .096. Just pulsed it on for like 4 seconds put the hot atty on the meter and it reads .023. Ok that's scary.

Mod is not hot. Just atty like it should be. But dafak is wrong???

 

[Justadude]

weird maybe the meter having issues... with the connection to that specific RDA

Good point. So I cleaned the meter. Put the cold atty on its at .144 like it should be. Fire it up. Put it on the meter. It reads .96 and sits there for 4 seconds then started going up and keeps going up as I'm writing this. Stopped at .135
Nope. Climbing. .140 now. Stopped at .144. Ok what the hell guys? I don't get it

 

[Justadude]

I tap the coil. Touch them. Touch the posts. Not moving. Stable as all hell below at .144 so I know I got a strong solid build. But God forbid I light it up. I wonder if I should just wick it and say F it and just vape but I don't know if this is safe.

 

[Justadude]

Wicked it juiced it fired up but didn't vape. Same scenario. Anyone got any ideas?

 

[TRIPDUBZ]

Hrm I have never used nichrome and can't comment on that. However, when you say "regular old coils" are you referring to contact/compressed coils? As in the wraps are touching? If so, I'd like to relay a point that a friend of mine made, that if you think about the flow of electrons - there is a short across the coils... this might be involved in your problem, but more than likely (as previously suggested) it is a contact issue. Make sure there isn't a bit of wire stuck inside a post too - I had the same problem befofe and that was the culprit... Also maybe try filing your screw heads nice and smooth to ensure a good connection. Just some thoughs, I wish I knew more about the correlation between heat and resistance in different wire materials.

 

[Justadude]

Well I just took a part the whole atty except for the middle post that didn't want to come out cause this thing is brand new. But I took out the 510 pin and the coils and all the screws and even the orings.

Cleaned everything out and shook out anything that could have been stuck in those post holes. Reinstalled the same flippin coils just to see what was gonna happen and booooom - sitting stable at .144 like a boss.

Fire it up and down below .1 Ohm it goes then starts to rise. Now back up to .144

I've never seen anything like it but I'm aggravated as all effin hell

 

[Justadude]

Vaped it. I guess because there is juice on it it won't drop below .125 but then when I put it on the meter it rises back up to .144. AGAIN

so I guess I'm out 30 bucks stuck with a faulty atty?

 

[Justadude]

I thought last night that maybe that was the nichrome wire. Or the coil was bad or something. So I've build a whatever coil with like 8 wraps out of 24 kanthal and just like the dude above said the resistance went from higher when hot to lower when cooler.

Then wrapped nichrome 8 times around the same screwdriver diameter fired it up and same thing - higher when hot down to lower when cool.

That means that there is nothing wrong with the mutation X v3 atty after all.

I'll build another set today after work and let you guys know if the problem persists