Rebuild of Melo3 TC Ni/Ti not working properly (iStick Pico 75W)

[stamasd]

Let me start by saying that I've rebuilt my Kanger coils for a few years and I never had any problems doing that. I have tools, wire, cotton, ohmmeters etc.

Recently I thought I'd graduate into the higher league and start using a TC mod. I got myself an iStick Pico kit with Melo3 tank, used it for a little while with the EC coils and it's been working fine. I decided to rebuild one of my used coils into a TC Ni and/or Ti coil. I watched videos, done a lot of reading, seemed simple enough. Got some Ni200 and Ti wire, both in 28ga. I started with a nickel build, did 14 wraps on 4mm diameter like the original Melo Ni coils have, checked resistance - was around 0.12 ohms, good. Wrapped it in cotton, installed back in the coil case, checked resistance of rebuild coil - same. (BTW I use 2 separate ohmmeters to check, a coil ohmmeter and a separate precision multimeter). Placed coil in the tank base, checked resistance again, still good. Assembled the tank, put liquid on the coil and in the tank, screwed it in the Pico. Switched the Pico to TC mode, it doesn't work. The battery says "no atomizer" - it doesn't detect it. Checked assembled tank resistance again, it's still what it should be. But the battery will not recognize the coil/tank. Replaced the coil with a new prebuilt one, it works. Put my rebuilt one back in, it doesn't work.

I rebuilt that coil 2 more times, with new nickel wire in various resistances (once 0.15 ohm, once 0.22 ohm). None of these was recognized by the battery, same error "no atomizer" despite the coils and assembled tank checking fine with 2 different ohmmeters.

I then took a new coil, took it apart before it was even used, made a titanium build of 0.5 ohms (9 turns 28ga on 4mm). Again it checked fine with ohmmeter. Again the Pico says "no atomizer".

I'm obviously doing something wrong, but I can't figure out what. I would appreciate any help I can get.

 

[Imfallen_Angel]

Hi,

Here's my guide for this very type of coil cartridges.

Vaperrasso cCell rebuilding

If you can post a few pictures of what you did I can probably assist.

Note that your ohm reading appears to be very low from what you're saying. You shouldn't go lower than 0.2, preferably try to get to 0.3-0.4 range.

Depending on how you're doing the wicks, your coil might be touching the sides, or not spaced correctly.

But sounds like there's a bad contact somewhere.

 

[stamasd]

Well, the original Ni coils for the Melo3 are 0.15 ohm, and I've seen a rebuild of this coil on youtube with 0.11 ohms IIRC so even lower than my original one. I also went above 0.2ohms with one of the rebuilds, it didn't make a difference. Nor did the titanium 0.5ohms (which is also what the original TC Ti coils for the Melo3 are).

This is a vertical coil, "cartomizer" style. The coil sits vertically in the middle. I do a 2-layer wrap with a japanese cotton strip, the first layer separates the coil from the descending wire from the top of the coil, the next wrap covers that wire too. Then at the bottom, the wire coming from the top of the coil gets connected to the coil case, and the wire from the botton to the central post, separated of course by the silicone insulator. It's a simple build, and on the ohmmeter it reads correctly but doesn't work on the battery.

Looking at your tutorial, that's pretty much exactly what I'm doing. I'm quite pleased with how it comes out, but... they don't work.

Thanks for the reply!

Edit: I'm beginning to wonder if there's something wrong with the iStick rather than my coils... I've been trying to update its firmware, but it's not recognized either by the original firmware updater, or by ArcticFox. I've seen reports in a few places that they're finicky as to which USB cables they work with, but I've tried 4 different cables including the original one from the box, neither works. I wonder if I got a counterfeit somehow... though it has the CoA on the box. Unless they started faking those too. In any case I have another iStick Pico being shipped, I'm curious whether my homemade coils will have the same effect on that one.

 

[IMFire3605]

Well, the original Ni coils for the Melo3 are 0.15 ohm, and I've seen a rebuild of this coil on youtube with 0.11 ohms IIRC so even lower than my original one. I also went above 0.2ohms with one of the rebuilds, it didn't make a difference. Nor did the titanium 0.5ohms (which is also what the original TC Ti coils for the Melo3 are).

This is a vertical coil, "cartomizer" style. The coil sits vertically in the middle. I do a 2-layer wrap with a japanese cotton strip, the first layer separates the coil from the descending wire from the top of the coil, the next wrap covers that wire too. Then at the bottom, the wire coming from the top of the coil gets connected to the coil case, and the wire from the botton to the central post, separated of course by the silicone insulator. It's a simple build, and on the ohmmeter it reads correctly but doesn't work on the battery.

Looking at your tutorial, that's pretty much exactly what I'm doing. I'm quite pleased with how it comes out, but... they don't work.

Are you putting the mod into the proper TC mode, there are multiple, TC Ni (Ni200), TC Ti (Titanium), TC SS (Stainless Steel), and TCR (this is more advanced where you put in the variables to adjust output variables for the resistance climb of the metal you are using)? Each metal has its own TCR curve variables, as the wire heats its resistance climbs, and as it cools its resistance decreases, with Ni200 having the one of the lowest curves to predict accurately. If you are in TC mode TC SS and try to use an Ni or Ti wire, the pre-programmed TCR setting detects the resistance and somewhat knows a TC SS coil should be at or around a 0.3minimum, a 0.12 would be to low and ineffective. If it is working with known pre-made TC coils in proper mode, then you could possibly have a short somewhere the mod is detecting your Ohm readers are not.

0.12 to 0.2 to 0.25 is about par for a Ni200 coil, though most mods that support Ni200 in TC mode 0.05 is base minimum which the Pico supports as absolute lowest, Ti you would be looking at a build that starts around 0.3, SS316L wire about 0.35 or so minimum.

 

[Imfallen_Angel]

It did sound correct the way you described it, so just trying to see where the issues is.

It's a very simple coil to rebuild, so it can't be that many things....

Did you try your tank's base (with the rebuilt coil) on your tester first? Sounds like you have, but in case.

Have you re-tested your base with a factory coil on your Pico?

Just process of elimination.

 

[Imfallen_Angel]

Another thing is.. are you rebuilding the exact same cartridge here. Check the screw thread at the bottom, you can sometimes crack these shell that would cause this issue.

 

[stamasd]

Are you putting the mod into the proper TC mode, there are multiple, TC Ni (Ni200), TC Ti (Titanium), TC SS (Stainless Steel), and TCR (this is more advanced where you put in the variables to adjust output variables for the resistance climb of the metal you are using)?

Yes, I'm putting the Pico in TC-Ni mode. I'm aware of the different TCRs for different metals etc. And of course for the titanium rebuild I used TC-Ti.

It did sound correct the way you described it, so just trying to see where the issues is.

It's a very simple coil to rebuild, so it can't be that many things....

Did you try your tank's base (with the rebuilt coil) on your tester first? Sounds like you have, but in case.

Have you re-tested your base with a factory coil on your Pico?

Just process of elimination.

Yes, I have tested the base with the rebuilt coil, and also later when I assembled the full tank with the rebuilt coil in. They test fine on 2 separate ohmmeters. When I use a factory coil, it works fine.

One weird thing is that the Pico reads the rebuilt coil as 0.00 ohms. Not sure why. But then the Pico is a bit weird that way, if I remove the tank completely it also reads 0.00 ohms (instead of infinite ohms).

Another thing is.. are you rebuilding the exact same cartridge here. Check the screw thread at the bottom, you can sometimes crack these shell that would cause this issue.

Not sure what you mean by that.
Keep'em coming! I'm sure there must be a way to figure it out.

 

[Imfallen_Angel]

Ok, let's see...

Turned the Pico off then back on?
Unlocked the ohms?

Can you fire them on your tester? (if your testers have the fire capacity)

Test them on another mod?

 

[stamasd]

Ok, let's see...

Turned the Pico off then back on?
Unlocked the ohms?

Can you fire them on your tester? (if your testers have the fire capacity)

Test them on another mod?

I rebooted the Pico many times. I take the battery off and then put it back in. That unlocks ohms and everything else. My tester can't fire coils, it's a simple ohmmeter. I don't have another mod to try them in - this is my first "serious" mod. Everything else I've got is a pile of eGo batteries. I know enough not to try these coils on those.

 

[Imfallen_Angel]

I've done so many of these rebuilds that I'm sure that I've seen it happen to me at the beginning and it was just a case that the coil was touching (wraps) as I was screwing it in the base and pushing just enough to cause a drop in resistance to give that message.

When you put the coil inside the shell, do you have it far up enough? so that when you put the rubber insulator to separate the legs, it doesn't touch the bottom of the coil?

 

[Imfallen_Angel]

ok.. hmm... note that ohmmeters can be finicky and act a bit different as a mod will when reading, some can be more forgiving, other's less.

 

[stamasd]

I haven't checked that visually, but if I had a short inside the case when screwed in, I'd expect that it would alter the ohms I'm reading with the coil mounted on the base. That is not the case.

 

[Imfallen_Angel]

Also.. when you fire a coil the very first time, it WILL change the resistance as the first "burn" acts a bit like a "tempering the metal" phase and it can cause the resistance to change.

 

[stamasd]

I agree that ohms are not equal to ohms. But here's a counter-example: one factory coil mounted in the pico reads 0.32 ohms. The same coil when taken out and checked with my ohmmeters, it's 0.29-0.30. It's not that much of a difference.

 

[stamasd]

Also.. when you fire a coil the very first time, it WILL change the resistance as the first "burn" acts a bit like a "tempering the metal" phase and it can cause the resistance to change.

Except... none of my rebuilt coils have been actually fired, as the Pico refuses to do it. I have nothing else to fire them with, the ohmmeters are low power and don't pass enough current through the coils to even get them warm.

 

[Imfallen_Angel]

I agree that ohms are not equal to ohms. But here's a counter-example: one factory coil mounted in the pico reads 0.32 ohms. The same coil when taken out and checked with my ohmmeters, it's 0.29-0.30. It's not that much of a difference.

yeah it's not, but if you're on the edge of the mod being able to read it or not, that tiny difference can be all that's needed to give you a headache.

 

[Imfallen_Angel]

Except... none of my rebuilt coils have been actually fired, as the Pico refuses to do it.

I figured, but just wanted to throw it out there for info purpose.

 

[Imfallen_Angel]

Check the legs tiny bits sticking out, which you would have cut close to the insulator...

You might have cut too short and it might just not be giving you enough contact... enough for the meters, but the mod might be seeing it as a poor contact.

 

[stamasd]

Here are some pictures of my titanium rebuilt coil.

Dropbox - 1.jpg
On the side. It's made from the body of an ECL 0.18 ohm coil. Shouldn't matter right, metal is metal.

Dropbox - 2.jpg
Contacts up. Sorry, my phone camera won't cooperate this is the best shot out of seven.

Dropbox - 3.jpg
Central post removed. Inner wire at the top, outer wire at the bottom.

Dropbox - 4.jpg
Different angle; inner wire at 9 o'clock, outer wire at 3 o'clock

Dropbox - 5.jpg
Top side.

 

[IMFire3605]

From those pictures, especially #4, the negative (outer wire) could be to long and causing a short when screwed into the base, it should be flush with the rubber insulator as it has enough contact along the barrel where it is sandwiched in with the insulator. Best way I found to do that was with old protank heads, instead of cutting it, take the leads, pinch the coil head top and at bottom pin, then wiggle and twist the leads until they snap off. Ni200 will take a while to do this being such a soft metal, but Ti and other wires will be a lot easier being harder and more brittle. Also take into account with a TC coil, do not wrap them where the windings are touching, you need space between them so not to cause hot spots and even heating along the whole coil, this will throw off the TC readings as well as it could throw off the resistance reading, especially with Ni200, use a machinist screw as your wrapping mandril that will fit the hole at the bottom, then once seated back the screw out, you'll load the coil from the top of the head.