SXmini M Class (TEMP CONTROL)

[chia]

No Chia, that would have no effect. The only important thing is that the temperature sensor on the chip is the same temp as the coil when the resistance baseline is initially set. The ambient temp doesn't really matter either. The temp could be 40F or 100F and it wouldn't matter, as long as the temp sensor on the SX350J board is the same as the coil temp during the initial baseline setting. Once the temp is equal between the two and the initial resistance is measured it will be able to know the temperature of the coil using the coefficient after that based on the resistance reading. For example, if the board temp is 83F and the resistance of the coil reads 0.22 during calibration, the chip can now use the coefficient to calculate any other temp based on the resistance of the coil as it changes. The properties of pure nickel are quite well known, reasonably stable, and has a big enough change of resistance in relation to temperature changes to be accurate for calculating the temp of the coil. That is the reason nickel was chosen as the material best used for this purpose.

In theory, if you had a method of heating the coil and the chip's sensor equally to 400F it would be just as valid a baseline as if it were done at 70F. In reality, the chip would have turned off at the temp limit setting (which is well below 400F) so that really wouldn't work above the chip's temp cutoff limit. So in actuality, both the coil and the chip's temp sensor need to be at the same temp within the limitations of the chip's ability to operate... or under the chip's cutoff point for the baseline reading. So without the physical equipment to bring the chip sensor and coil to the same temp, just letting them both settle to ambient temp works well enough for the baseline.

So once a known baseline temp to resistance is set with both the chips sensor and the coil being at the same temp, the chip will always know the temp based on the baseline readings and the current resistance of the coil. This is true unless for some reason the coil resistance changes. Since the properties of nickel are very stable, only outside influences like poor atty connection, loose coil wires, or a build-up of gunk on the coil, or some other outside change would cause a significant enough difference in resistance for this to be an issue. Ambient temp changes should have no effect on the SX350J's ability to regulate temp correctly.

TL;DR: Not a worry

Hi
Hey thanx for the explanation.. Here's another one..
Usually when I build a coil I use an ohm meter the test the resistance and them set it on the mod for a confirmation.. Sometimes there's a difference, say ohm meter 0.09 and mod 0.083.. Close enough? Or what is an acceptable difference between the 2? Sometime there is a 0.02 difference also..

 

[2legsshrt]

Hi
Hey thanx for the explanation.. Here's another one..
Usually when I build a coil I use an ohm meter the test the resistance and them set it on the mod for a confirmation.. Sometimes there's a difference, say ohm meter 0.09 and mod 0.083.. Close enough? Or what is an acceptable difference between the 2? Sometime there is a 0.02 difference also..

Thats what I end up with also ohm meter is always about .02 higher then the SX so I just figure on that.I kinda think the SX is right.

 

[Jazzman]

Hi
Hey thanx for the explanation.. Here's another one..
Usually when I build a coil I use an ohm meter the test the resistance and them set it on the mod for a confirmation.. Sometimes there's a difference, say ohm meter 0.09 and mod 0.083.. Close enough? Or what is an acceptable difference between the 2? Sometime there is a 0.02 difference also..

I think the SX350J is very accurate in resistance reading, I would trust the resistance reading from that before I trusted an inexpensive ohm reading box. But regardless, the SX350 is going to read the resistance and base all coefficient calculations based on it's own resistance reading, so right or wrong that's what's going to be used right? So since you have no manual control over it's resistance reading, don't stress and just go with it.

 

[chia]

K guys .. Thanx

 

[JimScotty0]

You guys are much more technical and knowledgeable about this than I am. I know enough not to blow myself up. I have this set-up using power+. I am assuming that because the 26 gauge is longer with 7/6 wraps and thicker, it takes longer to heat up the coil (I was using standard mode with the 28 gauge with 6/5 wraps). Standard mode worked best with the 28 gauge... at least the way I had it set up. Regardless, the 26 gauge is giving me denser clouds and more flavor. I'm sure this isn't the end-all for me, but it is progression.

I have found the ramp up time to be a few seconds longer using 26ga. You can try the powerful and powerful+ settings to give that a boost but I am finding a need to increase the Joules from around 18-22J when using the 26ga wire. Even a bit more when using the 26ga NI200 twisted with 28ga Kanthal but the clouds and flavor are better. But I have had to set the temperature quite a bit lower too since it seems to heat up about 100F less than with the 28ga.

I wonder if the SX350J chip is tuned more for a 28ga NI200 wire. With the 28ga I also use between 14-18J too which is much less than what I use with the 26ga.

 

[JimScotty0]

I for one, is glad you bought this up..
Say we do the build at nite when it's cool and the reading is 0.07, and the next day we bring the mod out daytime when it's hot and humid.. Does it have any bearing or effect on how the chip works properly? Or even in the day where we do the build in an air-con room at 20deg c, bring it out to vape at 33deg c... What happens then? Is it still considered as 'accurate' and proper?

It should still be accurate since you calibrated it when the mod and atty were stabilized at the same temperature.

 

[JimScotty0]

No Chia, that would have no effect. The only important thing is that the temperature sensor on the chip is the same temp as the coil when the resistance baseline is initially set. The ambient temp doesn't really matter either. The temp could be 40F or 100F and it wouldn't matter, as long as the temp sensor on the SX350J board is the same as the coil temp during the initial baseline setting. Once the temp is equal between the two and the initial resistance is measured it will be able to know the temperature of the coil using the coefficient after that based on the resistance reading. For example, if the board temp is 83F and the resistance of the coil reads 0.22 during calibration, the chip can now use the coefficient to calculate any other temp based on the resistance of the coil as it changes. The properties of pure nickel are quite well known, reasonably stable, and has a big enough change of resistance in relation to temperature changes to be accurate for calculating the temp of the coil. That is the reason nickel was chosen as the material best used for this purpose.

In theory, if you had a method of heating the coil and the chip's sensor equally to 400F it would be just as valid a baseline as if it were done at 70F. In reality, the chip would have turned off at the temp limit setting (which is well below 400F) so that really wouldn't work above the chip's temp cutoff limit. So in actuality, both the coil and the chip's temp sensor need to be at the same temp within the limitations of the chip's ability to operate... or under the chip's cutoff point for the baseline reading. So without the physical equipment to bring the chip sensor and coil to the same temp, just letting them both settle to ambient temp works well enough for the baseline.

So once a known baseline temp to resistance is set with both the chips sensor and the coil being at the same temp, the chip will always know the temp based on the baseline readings and the current resistance of the coil. This is true unless for some reason the coil resistance changes. Since the properties of nickel are very stable, only outside influences like poor atty connection, loose coil wires, or a build-up of gunk on the coil, or some other outside change would cause a significant enough difference in resistance for this to be an issue. Ambient temp changes should have no effect on the SX350J's ability to regulate temp correctly.

TL;DR: Not a worry

Well said!

 

[JimScotty0]

Thats what I end up with also ohm meter is always about .02 higher then the SX so I just figure on that.I kinda think the SX is right.

I have found my Eleaf ohms checker to be much higher on the lower ohms builds.

 

[Yozhik]

I have found the ramp up time to be a few seconds longer using 26ga. You can try the powerful and powerful+ settings to give that a boost but I am finding a need to increase the Joules from around 18-22J when using the 26ga wire. Even a bit more when using the 26ga NI200 twisted with 28ga Kanthal but the clouds and flavor are better. But I have had to set the temperature quite a bit lower too since it seems to heat up about 100F less than with the 28ga.

I wonder if the SX350J chip is tuned more for a 28ga NI200 wire. With the 28ga I also use between 14-18J too which is much less than what I use with the 26ga.

Powerful/Powerful+ actually seems to provide less power in Joules mode than Standard. This is based on data vlad1 provided using an Oscope capture. We're currently seeking to understand why this is from YiHi, but haven't gotten an answer thus far.

 

[Jazzman]

Thats what I end up with also ohm meter is always about .02 higher then the SX so I just figure on that.I kinda think the SX is right.

I also choose to believe the SX is more accurate 2legs, because if it's not it won't be able to regulate temp well at all. Just the fact that the SX has much greater resolution than a typical standalone ohm meter... the SX displays to 3 decimal points, or thousandths of an ohm (although I have heard internally it is actually measuring and basing it's calculations on 4 decimal places which is even better, but I can't absolutely verify that) leads me to believe it is probably using high quality components internally to measure that and my standalone box reads to 2 decimal places. I think the DNA40 is also quite accurate and I find the resistance reading between my SX350J and DNA40 box to be dead on between both devices, and yet my cheaper standalone box is a little off.

I know the amount of decimal places it reads is not a true indicator of accuracy, but a device that calculates temp from resistance would have to be pretty accurate I would think to be able to do that well. And the SX board sure seems to do temp well, at least to me. I also have a lot of experience with SX350 chips since they first came out (before the J chip) and they have all been very accurate chips and I have no reason to believe this chip is any different.

Just anecdotal evidence I realize, but if I were a betting man my money would go on the SX350J chip and not the standalone cheaper box... and I'd probably give odds.

 

[JimScotty0]

Powerful/Powerful+ actually seems to provide less power in Joules mode than Standard. This is based on data vlad1 provided using an Oscope capture. We're currently seeking to understand why this is from YiHi, but haven't gotten an answer thus far.

Yeah, I saw Vlad1's post quite a while back about that and feel that may be the case. I probably use standard mode more anyway but I think the higher in Joules you go the more pronounced it is with those modes. It seems to work right at around 14J, but at around 20J or so it seems to have a negative effect. I don't remember what Joules setting Vlad1 had it set to when he ran that test. Too tired now to find it.

 

[Yozhik]

Thats what I end up with also ohm meter is always about .02 higher then the SX so I just figure on that.I kinda think the SX is right.

With low ohm resistance, a simple ohmmeter will measure the resistance of the connections as well as the low ohm device. It may also heat up the coil if the measurement current is too high, adding more inaccuracy. Thus to get a more accurate measurement, one solution is to use four-wire resistance measurement:

Kelvin (4-wire) resistance measurement : Dc Metering Circuits - Electronics Textbook

Four-wire sensing can still run into the same problem with measurement current affecting the resistance of the test load, but there's various solutions to that (e.g., Kerry D. Wong » Blog Archive » Accurate Milliohm Measurement

Regardless, I'm not sure exactly what method the SX Mini is using (there's a variety of ways to do milliohm measurement, even with just four-wire approaches), but my sense is that it's quite accurate.

On a sidenote, this also could be a reason why the SX Mini is limited to 0.3 ohms. An expensive, professional milli/micro ohm meter can measure a wide range of resistances very accurately (e.g., 1 micro ohm to 2500 ohms with a resolution of .1 micro ohm to 100 milliohms, depending on the load). A cheaper, but sufficiently accurate approach to milliohm measurement for TC, may only be accurate within a smaller range (e.g., up to 1 ohm).

 

[Silver5656]

So i've been reading as much as I can to catch up. I do have 2 dna 40's (a VS rdna 40 and a VF dna 40). I've been eager to pick up the sxmini m. Unlike the problems that i've experienced/read about regarding the dna 40 (and specifically the vaporshark), the only problem I've read about regarding the sxmini m is the paint flaking off. Are there any other issues? And has the paint issue been fixed?

 

[m00shie]

Mine was one of the early batch and yes, the paint is flaking off. If my assumptions are correct, the paint issue only applies to the silver/black unit. Good news is that Yihi has agreed to replace the defective paint issue which I am currently waiting for re-stock at the B&M I've purchased it from.

I believe that the new black surface has a rougher texture compared to a smooth surface on the defective units.

 

[Yozhik]

So i've been reading as much as I can to catch up. I do have 2 dna 40's (a VS rdna 40 and a VF dna 40). I've been eager to pick up the sxmini m. Unlike the problems that i've experienced/read about regarding the dna 40 (and specifically the vaporshark), the only problem I've read about regarding the sxmini m is the paint flaking off. Are there any other issues? And has the paint issue been fixed?

I've had no problem with my silver/black SX Mini's paint. I received mine a couple weeks after launch.

 

[dr g]

No Chia, that would have no effect. The only important thing is that the temperature sensor on the chip is the same temp as the coil when the resistance baseline is initially set. The ambient temp doesn't really matter either. The temp could be 40F or 100F and it wouldn't matter, as long as the temp sensor on the SX350J board is the same as the coil temp during the initial baseline setting. Once the temp is equal between the two and the initial resistance is measured it will be able to know the temperature of the coil using the coefficient after that based on the resistance reading. For example, if the board temp is 83F and the resistance of the coil reads 0.22 during calibration, the chip can now use the coefficient to calculate any other temp based on the resistance of the coil as it changes. The properties of pure nickel are quite well known, reasonably stable, and has a big enough change of resistance in relation to temperature changes to be accurate for calculating the temp of the coil. That is the reason nickel was chosen as the material best used for this purpose.

In theory, if you had a method of heating the coil and the chip's sensor equally to 400F it would be just as valid a baseline as if it were done at 70F. In reality, the chip would have turned off at the temp limit setting (which is well below 400F) so that really wouldn't work above the chip's temp cutoff limit. So in actuality, both the coil and the chip's temp sensor need to be at the same temp within the limitations of the chip's ability to operate... or under the chip's cutoff point for the baseline reading. So without the physical equipment to bring the chip sensor and coil to the same temp, just letting them both settle to ambient temp works well enough for the baseline.

So once a known baseline temp to resistance is set with both the chips sensor and the coil being at the same temp, the chip will always know the temp based on the baseline readings and the current resistance of the coil. This is true unless for some reason the coil resistance changes. Since the properties of nickel are very stable, only outside influences like poor atty connection, loose coil wires, or a build-up of gunk on the coil, or some other outside change would cause a significant enough difference in resistance for this to be an issue. Ambient temp changes should have no effect on the SX350J's ability to regulate temp correctly.

TL;DR: Not a worry

So I was thinking ... when YiHi says they recommend 0.065 ohms, what temperature is that?

 

[dannyben]

Both Wetvapes.com YIHI SX MINI M CLASS and Vapordna.com SX Mini M Class 60 Watt Box Mod by YiHi state the opposite of what you do.

A conveniently placed Micro-USB charging port allows for simultaneous firing and charging.

What a shocker..... Less then 24-hours after my post, one of your mentions COMPLETELY removes any mention of the device being able to fire while charging!!! Coincidence? Or you think he contacted yihi to confirm and saw i was correct.

Keep up the good work fighting (and spreading erroneous and dangerous information) rather then confirming from the ONLY accurate source....YIHI.

So i've been reading as much as I can to catch up. I do have 2 dna 40's (a VS rdna 40 and a VF dna 40). I've been eager to pick up the sxmini m. Unlike the problems that i've experienced/read about regarding the dna 40 (and specifically the vaporshark), the only problem I've read about regarding the sxmini m is the paint flaking off. Are there any other issues? And has the paint issue been fixed?

I've had no problem with my silver/black SX Mini's paint. I received mine a couple weeks after launch.

Actually silver/black means your unit has a silver sleeve and a black frame or main body.

As to the finish.... No this problem has not be corrected yet and it is on-going for both units that have black in them. Yihi has now completely halted manufacturing of both of these finishes and is working on a fix. They will not start shipping again until they rectify the problem and consumers can receive units with the quality you would expect from a $200 device and Yihi.

So...... if you are thinking of picking up one of these devices i would suggest the grey or waiting a few weeks if you want a black. And even then asking your vendor the production date of the unit. Because if they ship you one that they currently have in stock, you will most probably have an issue with the finish.

 

[dannyben]

So I was thinking ... when YiHi says they recommend 0.065 ohms, what temperature is that?

The temperature is irrelevant. That is for the users preference and/or safety concerns. The recommendation of a 0.065 build is where the unit is most accurate for producing (and staying closest to) the temperate you set.

 

[dr g]

The temperature is irrelevant. That is for the users preference and/or safety concerns. The recommendation of a 0.065 build is where the unit is most accurate for producing (and staying closest to) the temperate you set.

Temperature is critical. The ambient temperature changes the baseline reading of the device, so 0.065 means a different coil in different places.

It also means the same coil may NOT be 0.065 in different places.

 

[dannyben]

Temperature is critical. The ambient temperature changes the baseline reading of the device, so 0.065 means a different coil in different places.

It also means the same coil may NOT be 0.065 in different places.

My bad..... i thought you meant what temperature to set the device too.

Thats a good question. Room (or ambient) temperature could vary greatly for many.