Coils changed resistance?

[buildabane]

Before I start: I do know battery safety, I use Sony VTC5's, and I use an ohm reader before putting anything on a device.

Yesterday I wrapped dual parallel coils using 26 gauge kanthal. After some pulsing and pinching, they came out at .18 ohms. Wicked it and fired it up (Using a Tobh, with a Chuff and extra airflow). Crazy vape. Dense, hot, and powerful. Continued to vape on these until this morning when I took a break until about 4:00 PM. Around this time, the vape started to smooth out, and wasn't putting out the heat and vapor (not even close) to what it was. I figured it was cleaning time, so I dry burned and rinsed, then re-wicked. Before vaping again, I threw it back on my ohm reader. It had jumped from .18 to .22, and was not fluctuating or skipping. I checked the coils and all of the leads are tightly clamped, and where they are suppose to be.

I've never had coils do this before - Anyone know why this might happen? Any fixes or anything I can do to prevent it?

I want to keep my coils firing the way I built them!

 

[eyerhere]

I have had coils do that. Usualy as coils age they do pick up a few points. That sounds a bit quick possibly because it is a parallel its building gunk faster.

 

[dragonpuff]

Before I start: I do know battery safety, I use Sony VTC5's, and I use an ohm reader before putting anything on a device.

Yesterday I wrapped dual parallel coils using 26 gauge kanthal. After some pulsing and pinching, they came out at .18 ohms. Wicked it and fired it up (Using a Tobh, with a Chuff and extra airflow). Crazy vape. Dense, hot, and powerful. Continued to vape on these until this morning when I took a break until about 4:00 PM. Around this time, the vape started to smooth out, and wasn't putting out the heat and vapor (not even close) to what it was. I figured it was cleaning time, so I dry burned and rinsed, then re-wicked. Before vaping again, I threw it back on my ohm reader. It had jumped from .18 to .22, and was not fluctuating or skipping. I checked the coils and all of the leads are tightly clamped, and where they are suppose to be.

I've never had coils do this before - Anyone know why this might happen? Any fixes or anything I can do to prevent it?

I want to keep my coils firing the way I built them!

A change from 0.18 to 0.22 ohms is extremely small. It could be caused by anything - gunk on the coils, them moving a tiny bit when you wick them or tighten the post screws, etc... It's really not worth worrying about, because it will happen to you all the time as far as I can tell, your coils are still working exactly as you built them, so just enjoy them.

Now if you said your resistance jumped from 0.18 to 0.56 ohms or something crazy like that, that would be an issue! But a difference as small as 0.04 is to be expected.

Also, ohm meters (I mean all ohm meters, from the little black boxes to digital mods) are only so accurate... even the most expensive ones struggle to measure resistances that low. It's quite possible that your resistance is exactly the same, and your ohm meter is just reading it a little differently this time. The ohm meter should be viewed as a more of a guide than anything else - it cannot give you a truly exact measurement. I usually assume my true resistance is most likely between + or - 0.05 ohms from what the meter reads.

This is more reason to be careful exactly how low you build your coils. You have a 30A battery, so the bare minimum build is 0.14 - but as you see, the resistance will change on its own a little. You're better off shooting for 0.20 ohms or higher so you don't have to worry about whether that little change could overdraw your battery.

 

[Ryedan]

Yesterday I wrapped dual parallel coils using 26 gauge kanthal. After some pulsing and pinching, they came out at .18 ohms. Wicked it and fired it up (Using a Tobh, with a Chuff and extra airflow). Crazy vape. Dense, hot, and powerful. Continued to vape on these until this morning when I took a break until about 4:00 PM. Around this time, the vape started to smooth out, and wasn't putting out the heat and vapor (not even close) to what it was. I figured it was cleaning time, so I dry burned and rinsed, then re-wicked. Before vaping again, I threw it back on my ohm reader. It had jumped from .18 to .22, and was not fluctuating or skipping. I checked the coils and all of the leads are tightly clamped, and where they are suppose to be.

I've never had coils do this before - Anyone know why this might happen? Any fixes or anything I can do to prevent it?

I want to keep my coils firing the way I built them!

When you put the RDA on the ohm reader, put your fingertips on the coils and give them a slight wiggle. You'll see the ohms change when you do that. I judge the tightness of the post screws by how little that changes. If I can get it down to +- 0.01 ohm I'm happy. Generally when my RDA resistance goes up by 0.04 ohms it's because the wires got a bit loose in the posts and going through the 'wiggle' process again fixes it for me.

 

[buildabane]

Thanks all - Dragonpuff - While that change may seem insignificant, it really did make a HUGE change in the vape quality. Don't worry, .17 is the lowest I will go. I generally build at .2, just trying out new things! But man, dual parallels were a pain to build!