Ohm Drop

[Vapemesilly]

I have 3 different RTA units. I've been building coils for a few months and have got pretty good at it. I'm not an expert but I'm not a rookie. I build with Kanthal, single coil and at .5 ohm. One of my RTA units, it is the Kanger RBA for the sub tank mini, has a small issue. When I fire up the new coil, it starts out at .50 to .55 ohm, which is perfect, but after a little vaping it drops down to .3 and stays there. It does this every single time. Still vapes fine but I can't understand why the ohms drop so much on this unit. I do not have this problem with my other two RTA's.

Any ideas?

 

[puffon]

Be sure the air flow pin on the RBA is tight. I use a small nail, through the air holes.
Also be sure the STM base 510 pin (floats in the rubber insulator) is making good contact with the RBA.
Press the base 510 on a table, as the RBA is screwed in, you can feel when it makes contact.
Other than making sure all connections are clean, and RBA screws are tight, I can't think of anything more that would cause fluctuating ohms.
Good Luck

 

[mhertz]

I had this happen too, but since it didn't bother anything, I just ignored it. After a rebuild it was always higher and then some time later settled down and never moved from there??? I can't remember if it was my STM or my lemo that did this... If it's a connection issue I just never understood why it was only intermittent i.e. just after a rebuild...

Edit: Though of course it has to be a connection issue, or some mod issue??? The funny thing was, for me, that the vape didn't change i.e. from when it was reading incorrectly til correctly. You would think the power output would feel highly changed. Mine btw changed from 1.2ohms about, and to 0.6 which was correct. And as OP, only 1 RTA of many, that did this...

 

[Cool_Breeze]

It might be that after going through some heat/cool cycles, the coil connections are making better contact.

 

[93gc40]

Might be that atomizer or head has a lot of internal resistance..... do regular coilheads act the same?

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[Vapemesilly]

No, they don't.

 

[93gc40]

No, they don't.

Then the rba base is the problem.... coil itself should not change ohm by more than a few hundreths. .5 to .45 meh.... .5 to .3 us a connection issue in the atty..

Could an isolator going bad.... starting to cause a short.

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[Vapemesilly]

Could an isolator going bad.... starting to cause a short.

I don't know what that means. Never heard it before.

 

[93gc40]

I don't know what that means. Never heard it before.

Isolators can break or can get worn out... just the affects of repeated heating and cooling can cause small cracks..... too small to see... but these Cracks give a path to ground for the current. This can be seen in intermittent shorts and resistance fluctuations. If the isolator is in a moving part or removable part. Like say a post or 510 pin. You can include friction and pressure the potential sources or wear.

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