iStick Pico resistance reading all over the place, faulty ohmmeter/rubber grommet to blame?

[Ionori]

I've been having problems using my istick Pico in TC mode since I got it last autumn, sometimes the mod would undershoot or overshoot the desired temperature, and the resistance it reads for the atomizer changes in unpredictable ways.

Now that I've discovered the ArcticFox firmware, I'm able to see live readings from the ohmmeter, and I'm seeing resistance jumping between 0.68 and 0.74 every few seconds even after several minutes of not firing, which is equivalent to an error of about 100C. I've checked the scratch code on the package, and the mod (or at least the package) is genuine eleaf, the tank is eGo ONE Mega and the head is CLR with my own 316 stainless steel 26 gauge wire contact coil.

I've read that using an atomizer with a rubber grommet (such as the CLR head) instead of RTA-style posts may lead to bad resistance readings and therefore TC mode problems. I've also read about faulty ohmmeters on some iStick Pico mods. Are these symptoms more likely to be caused by a faulty ohmmeter or the rubber grommet? Any relevant advice is appreciated.

 

[Ionori]

I've been having problems using my iStick Pico in TC mode since I got it last autumn, sometimes the mod would undershoot or overshoot the desired temperature, and the resistance it reads for the atomizer changes in unpredictable ways.
Now that I've discovered the ArcticFox firmware, I'm able to see live readings from the ohmmeter, and I'm seeing resistance jumping between 0.68 and 0.74 every few seconds even after several minutes of not firing, which is equivalent to an error of about 100C. I've checked the scratch code on the package, and the mod (or at least the package) is genuine eLeaf, the tank is eGo ONE Mega and the head is CLR with my own 316 stainless steel 26 gauge wire contact coil.

I've read that using an atomizer with a rubber grommet (such as the CLR head) instead of RTA-style posts may lead to bad resistance readings and therefore TC mode problems. I've also read about faulty ohmmeters on some iStick Pico mods. Are these symptoms more likely to be caused by a faulty ohmmeter or the rubber grommet? Any relevant advice is appreciated.

 

[classwife]

Moved you to Temperature Control from Ask The Veterans

 

[classwife]

Merged duplicate threads

 

[AtmizrOpin]

more than likely the rubber grommet. i stopped using premade TC coil tanks for that reason. their instability with resistance makes them a nightmare to use. i think my kanger subtanks were the worst offenders, horrible to keep stable.

i'd suggest learning how to build your own coils and do some shopping for an RTA that you would like.

 

[Eskie]

Yup, it's likely the grommet. There are some factory SS coils that do work well in TC, so it's not impossible, but it is more difficult, especially when you're the one putting it together. Having a solid point of contact for accurate resistance reading is an absolute requirement for TC to perform well, and it's going to be iffy with that style "RBA" (really just a factory coil that is rebuildbable, not a real RBA style deck). Bending the legs to be held in place is challenging on that style coil, whereas on a true RBA or RTA, you screw the coil legs into the metal post, which is far more reliable at maintaining consistent contact.

 

[Ionori]

Can rubber grommets really cause resistance readings to oscillate by 10% every couple of second even when the atomizer is cold and at rest? I certainly hope that's the case and that I will be able to report that the problem is indeed solved when my eLeaf Lyche atomizer with RBA head (which uses posts to hold coils) arrives.

 

[Eskie]

Can rubber grommets really cause resistance readings to oscillate by 10% every couple of second even when the atomizer is cold and at rest? I certainly hope that's the case and that I will be able to report that the problem is indeed solved when my eLeaf Lyche atomizer with RBA head (which uses posts to hold coils) arrives.

Could it? Probably. Could it be the mod? Unlikely, but not impossible. You'll be able to answer that when the new RBA head arrives.

 

[Ionori]

All right, thanks for your answers! Fingers crossed the new atomizer does the trick.

 

[sofarsogood]

TC control should have been ideall for new vapers but it's not working out that way because it's finicky. I run in TC mode with the AF firmware on a Pico but I rebuild on an rda and make certain the connections are solid and the coil a tiny bit spaced. Today I displayed real time ohms and yes the readout bounces around even with my build. But I get a consistant vape never the less.

Recently when I rewick or rebuild I do a cotton burn test at 420 F. I'm looking for the cotton to be barely singhed at that temp setting. I lock resistance at what ever value gets that result. I'm finding the coil is consistantly passing the test without adjusting the resistance. I'm vaping at 15 watts and just added a slight preheat for a fraction of a second. This seems to get the wire heating nicely even with my low watts. So far so good.

 

[Ionori]

TC control should have been ideall for new vapers but it's not working out that way because it's finicky. I run in TC mode with the AF firmware on a Pico but I rebuild on an rda and make certain the connections are solid and the coil a tiny bit spaced. Today I displayed real time ohms and yes the readout bounces around even with my build. But I get a consistant vape never the less.

Recently when I rewick or rebuild I do a cotton burn test at 420 F. I'm looking for the cotton to be barely singhed at that temp setting. I lock resistance at what ever value gets that result. I'm finding the coil is consistantly passing the test without adjusting the resistance. I'm vaping at 15 watts and just added a slight preheat for a fraction of a second. This seems to get the wire heating nicely even with my low watts. So far so good.

By how much of the total resistance does the resistance vary on your coils? Do you find that contact stainless steel coils are less consistent on their resistance value than stainless steel space coils?

 

[sofarsogood]

I've been having problems using my iStick Pico in TC mode since I got it last autumn, sometimes the mod would undershoot or overshoot the desired temperature, and the resistance it reads for the atomizer changes in unpredictable ways.

Now that I've discovered the ArcticFox firmware, I'm able to see live readings from the ohmmeter, and I'm seeing resistance jumping between 0.68 and 0.74 every few seconds even after several minutes of not firing, which is equivalent to an error of about 100C. I've checked the scratch code on the package, and the mod (or at least the package) is genuine eLeaf, the tank is eGo ONE Mega and the head is CLR with my own 316 stainless steel 26 gauge wire contact coil.

I've read that using an atomizer with a rubber grommet (such as the CLR head) instead of RTA-style posts may lead to bad resistance readings and therefore TC mode problems. I've also read about faulty ohmmeters on some iStick Pico mods. Are these symptoms more likely to be caused by a faulty ohmmeter or the rubber grommet? Any relevant advice is appreciated.

I'm also using AF firmware on a Pico. I adjust resistance where cotton singhes slightly a 420 F. Here is a screen display of set resistance and real time resistance immediately after a puff on a Pico and then a VTC mini. It jumps around. Never the less I'm getting a good vape that seems consistent depending on how saturated the wick is, which can vary a lot because i use a traditional style rda. How about put a video of what you see on your screen and post it here.

 

[AtmizrOpin]

res will fluctuate a tiny bit when the mod is idle due to board sending small pulses of voltage to the coil to check the resistance (joyetech and Evolv boards do this for resistance refinement purposes). every time this pulse happens, the coil is ever so slightly heated up and as a result the coil the res will vary, slightly. i also run the AF FW on my Pico and cuboid 200. it's basically EScribe for Joyetech boards. fun app to customize your device.

 

[Ionori]

res will fluctuate a tiny bit when the mod is idle due to board sending small pulses of voltage to the coil to check the resistance (joyetech and Evolv boards do this for resistance refinement purposes). every time this pulse happens, the coil is ever so slightly heated up and as a result the coil the res will vary, slightly. i also run the AF FW on my Pico and cuboid 200. it's basically EScribe for Joyetech boards. fun app to customize your device.

Damn, I didn't expect trying to get a consistent vape temperature would have me dealing with the observe effect like I'm doing quantum physics! Thanks for the information. Could you measure the live resistance range on the same atomizer in a cold state with both mods?

I'm also using AF firmware on a Pico. I adjust resistance where cotton singhes slightly a 420 F. Here is a screen display of set resistance and real time resistance immediately after a puff on a Pico and then a VTC mini. It jumps around. Never the less I'm getting a good vape that seems consistent depending on how saturated the wick is, which can vary a lot because i use a traditional style rda. How about put a video of what you see on your screen and post it here.

Thank you for the video! I see the Pico's readings vary a lot more (1.3-1.7 ohm) than VTC Mini's (1.35-1.5). One potential explanation is that the Pico is using a more powerful pulse to measure the coil's resistance, causing the coil to heat up more. I guess the grommet isn't necessary to explain the minute changes in resistance, but could explain why the device sometimes overshoots or undershoots the temperature significantly. Here are 2 live resistance graphs I've captured with my Pico (each graph shows 60 seconds):

CLR atomizer

ECR atomizer

 

[Eskie]

Are those recordings from that same coil you built? That much variation just should not be occurring. It might read differently from mod to mod as far as resistance (it shouldn't but on some mods it does) but it should not demonstrate that type of variable resistance at rest. I'll be curious as to what happens when your new RBA arrives.

 

[Ionori]

Are those recordings from that same coil you built? That much variation just should not be occurring. It might read differently from mod to mod as far as resistance (it shouldn't but on some mods it does) but it should not demonstrate that type of variable resistance at rest. I'll be curious as to what happens when your new RBA arrives.

Oh, no, each head has its own coil with a different number of loops based on the available space.

 

[David Wolf]

I'm also using AF firmware on a Pico. I adjust resistance where cotton singhes slightly a 420 F. Here is a screen display of set resistance and real time resistance immediately after a puff on a Pico and then a VTC mini. It jumps around. Never the less I'm getting a good vape that seems consistent depending on how saturated the wick is, which can vary a lot because i use a traditional style rda. How about put a video of what you see on your screen and post it here.

Nice video, I will have to check out the resistance variance when I put AF on my Pico. Your VTC mini looked quite stable there. Same atty model on both?

 

[sofarsogood]

Nice video, I will have to check out the resistance variance when I put AF on my Pico. Your VTC mini looked quite stable there. Same atty model on both?

99% of the time I'm using the same atomizer, the only one I've stockpiled so far. (I take a few puffs every day on a Nautilus mini, still a great vape. If I'm comparing I'm going to use the same atomizer with the same build for consistancy.