Odin Mini (75C) - Cold Resistance reading off.

[mbo]

Hi everyone,

first post here so I hope I am doing this right.

I am running an Odin Mini 75C with a Juggerknot MR.

The Odin is in use for a year now and works flawlessly, the Juggerknot is about two weeks old.

At first it worked fine in TC but after about a week it stopped firing in TC.

Since the issue is only with the Juggerknot MR I rebuild about 30 times, cleaned it multiple times and even got a replacement 510 kit from the awesome QP support.

So the 510 pin, insulators and post were replaced.

Since I can't find anything else I fired up escribe and did some testing which is why I am writing here, attached are two screenshots, one shows 3 measurements on a room temp coil.

The room temp is showing 5-10°C above the actual room temp though.

The other one is me firing in watts mode.

As you can see the cold ohms reading is way above the live ohms.

If I measure over an over there are jumps, sometimes of about .100 but the live ohms are always as shown in the picture.

Live ohms are working as expected but for some reason the measured cold ohms reading is always way off.

I searched for similar issues but couldn't find anything that helped.

Do you guys have any idea what can be done to fix this?

Edited April 3, 2022 by mbo

[BillW50]

You didn't mention what kind of wire you are using. Looks like some SS type to me, maybe SS316L. Higher resistance cold than hot sounds like you are using contact coils (non-spaced). If true, the wraps (some) are likely shorting when warm. Some use spaced coils to avoid such hotspots.

The higher room temperature reading is due to the thermals (Case Analyzer) are not calibrated. Which isn't surprising since Dovpo and some other manufactures don't bother doing them and just use Evolv's default values. You might find someone who has done it for the Odin Mini already and just use those values.

Another thing to consider, while I haven't heard anything about the Juggerknot MR, but some atomizers are not stable enough to do TC well. For example Kayfun recommends do not to use resistance under 0.4Ω (according to PBusardo). But many do it anyway. If an atomizer uses gold plating for electrical contact, there is a good chance it is likely just fine.

[mbo]

Thank you very much for the in-depth reply.

It is indeed SS316L, I tried normal round wire, superflat-quad and clapton.

I spaced the coils but those I tried were all around between 0.3Ω and 0.4Ω so I will try a higher resistance build.

As soon as the battery is low enough I will try the case analyzer and see what that does.

 

The one thing that doesn't make sense to me is that the live ohms are super stable and it seems like TC would work perfectly if the manual measured value was the same.

Setting the resistance manually does not help though.

 

Thanks for all the info, I will try some more things.

[Wayneo]

While I agree with the vast majority of what @BillW50 wrote, it could also be as simple as your mod and coil was not at room temp when you measured the coil. Or the positive pin on the atty needs to be tightened.

On 4/3/2022 at 8:51 AM, mbo said:

I spaced the coils but those I tried were all around between 0.3Ω and 0.4Ω so I will try a higher resistance build.

That range should be fine, and presumably did work fine for first week

On 4/3/2022 at 8:51 AM, mbo said:

The one thing that doesn't make sense to me is that the live ohms are super stable ...

As seen in Atomizer Analyzer, right?

On 4/3/2022 at 8:51 AM, mbo said:

Thanks for all the info, I will try some more things.

What more things woul that be?

[mbo]

Sorry for not getting back to you guys.

The resistance was jumping in the atomizer analyzer but was stable but below measured when I fired the device as soon in my initial screenshots.

So I took the Odin apart and noticed brown residue around the soldering on one connection.

Since I didn't solder anything for years I went the easy route and ended up getting a Thelema Solo.

That one reads stable resistance.

Since I got a replacement now I will see if I can fix the odin issue if I resolder everything and clean the device.

I figure there must have been some leakage through the 510 connector at some point.

Thank you all very much for the assistance.

[BillW50]

53 minutes ago, mbo said:

So I took the Odin apart and noticed brown residue around the soldering on one connection.

Sounds like soldering flux. You use soldering flux with heat and solder as it cleans the connection while soldering. Although once the solder cools, it should be removed with alcohol or electronic cleaner. Leaving it on can eat away at the connection with time. Most solder has a small amount of flux too. Still should be cleaned afterwards.

Edited April 7, 2022 by BillW50