Anyone have heads fail where resistance rises until your mod says "Open"

[DaveP]

Lately, I have had this problem where I'm vaping and the vapor drops off to the point where I check the voltage and the resistance to see what's going on. I'll find that my voltage hasn't changed, but the resistance of the coil has risen significantly. I'll up the voltage and get the vapor level back up, only to have the same problem again, then the coil will eventually fail or the resistance goes so high that the head just won't produce a satisfactory vape anymore.

I'm not vaping high voltage or sub ohm resistance. I'm using 1.8 or 2.0 ohm stock Aspire Nautilus or Kanger Aerotank heads at 3.3 to 3.7 volts. I got so frustrated with the Nautilus coils that I shelved them and bought the Kanger Aerotank. The tank came with the new head with the oval side holes and my spares came with the 2 hole configuration. My first head worked just fine for several hours and then rose from 1.8 ohms to 2.4 and finally 4 ohms before I changed it. The second head (out of the 5 pack) lasted most of the day and then started rising in resistance and went to "open" on my Provari.

I've changed over to my Sigelei Zmax V3 just to eliminate the Provari from the equation. I'm on my third Kanger Aerotank head in 3 days now and it seems to be working fine so far. Time will tell. Head #3 on the Aerotank is working fine after several hours of use, but it will take 24 hours to tell if it's going to fail similarly.

I'm not really convinced that the mod has any bearing on the issue. When I remove the head from the Provari and install it on the Zmax the resistance reads the same and the vape is off. Both mods are producing rock steady voltages.

Anyone else having a similar issue with heads all of a sudden or do I have a little black cloud following me around? I'm suspecting issues with heads, but Aspire AND Kanger both having contact issues with the wires in the head base? Rising resistance has to be bottom pin contact. A failed coil in a dual coil head will just make the head suddenly rise to double resistance, not rise in small increments until it reads open or gets so high it's unusable.

 

[danny4x4]

I've encountered this issue only with bottom coil clearos.
2 possibilities I think,

1) legs of the coils are secured by grommet only and may shift/move, hence contact varies, leading to varying resistance.

2) contact of head with the base. Maybe, juice has seeped in between the contact points? I'm not referring to the 510 connection, but rather the portion where the head is screwed onto the base.

Sometimes the resistance rises, and just by firing the device, resistance drops back to normal.

There were times when the resistance would continually rise until it becomes an open connection. What I did was to very very slightly turn the base of the clearo to loosen it, then fire it. Resistance drops back to normal.

That said, the heads with rising resistance were stock heads which were using 32awg or higher. With my own coils using 30awg, the problem is mitigated as the wires are thicker and hence fit tighter and less prone to movement and rising resistance.

Tension coiling (there's a thread on ECF, I think) might fully solve the problem. But I'm too used to my way of coiling to try it out.

 

[Miata GT]

I've noticed that as my old T3S attys get used (they're all about 6 months old now) the resistance starts to rise from gunk building up on them. This keeps the coil from transferring its heat which raises the resistance of the wire. I clean and dry burn them and they go back to normal.

I read your other post about the resistance suddenly increasing on newer coils then failing. This sounds like a defect issue somewhere.

 

[DaveP]

My Provari just came back from Provape where they apparently changed the board for a switch issue. When it came back it was pristine, clean, and almost like a new mod. I check and clean my connections frequently and the battery connection is good. I use Noalox here and there to maintain connectivity.

I though maybe the problem was something to do with one mod, but I've changed back and forth between the Zmax and the Provari and found it to be consistently happening on the Nautilus tank heads. I've actually had it happen on the first two Kanger Aerotank heads, but not as consistently. If a resistance rise occurs on one mod, the other reads the same on the atomizer in question and so does my ohmmeter. Loosening and tightening the tank or cleaning the connection produces no change in the reading or the vape quality. It's an actual issue with coil connections inside the head. I wrote down the resistance readings I had when I removed each of 6 coils and we rechecked them all at the vendors store. They all read the same value I wrote on the ziplock package label.

Both the heads its happened on have had white silicone grommets. Silicone takes higher temps without burning. The old grey material was stiffer and provided more pressure, apparently. I'm wondering if the change to white silicone grommets is resulting in lower pressure against the wire.

It's kind of a mystery. The third head in my new Kanger Aerotank is performing fine after two days of use. The first two failed in several hours to a day with a double in resistance or more. What started me checking this problem out was the sudden Nautilus issues. I'm thinking my vendor has some bad stock. I guess what I need to do is order some Nautilus heads from another vendor.

 

[DaveP]

Update: The third Kanger Aerotank head that had lasted the longest started failing in the car on the way home today. When I got home I took the pin out of the end cap and looked inside. There was a significant indentation in the silicone where the wire pressed against the center pin. Looking around the outside of the silicone grommet I couldn't see evidence of the negative lead that touches the body. I removed the grommet with my fingernails and saw no wire on the outside, so I popped off the chimney and looked down inside. It's hard to tell much from that angle so I used a toothpick to gently push the two coils out the top onto the counter. I felt no resistance as I pushed but both the legs were broken off the side of the two coils and laying loose when the assembly came out of the body.

Were the wires cracked and barely touching when it suddenly started rising in resistance? Who knows. Over a few minutes the coil went from 2.1 ohms to 9.9 ohms on my Sigelei Zmax. When I pulled the grommet and pushed out the contents the two legs on the negative side of the coils were broken off. The assembly came out easily, so I'm sure I didn't break 32ga Kanthal wire pushing two coils with free legs from the pin and grommet being out. Another interesting observation was that the only wicking was inserted into coils. There was no blanket like the Aspire heads use. I guess the wicks are right next to the holes where juice can contact them directly.

I installed a new coil and got great vape again.

 

[DavidOck]

I've read around here that some have been having similar issues with the NR-R-NR coils, that are, I think, the newer style. Reported problems seem to be the silver solder connection between the non-resistance and the resistance wire breaking. I rebuild all my Kanger styles, with straight Kanthal, so haven't experienced it. But what you're describing sounds like the same thing... gradual increase in resistance, as the connection breaks down. And, of course, once the wire breaks, it's only friction that makes a connection.

If that's the case, short of recoiling your own, or finding some of the older style (which didn't have the NR-R-NR coil), it might just be necessary to have a lot of spares...