New Kangxin 50W TC device - Mini VF KX-50D: single 18650; LED torch; USB charge; multiple colours

[Fernand]

In all fairness Gearbest suddenly offered me a refund or resend today.

Took a while but they must have consulted the marketing group of the Central Party Committee.

Good luck in your case.

A new one with a seemingly similar chip and a little lower max power, but integral battery for under $30 shipped (!).

Smocare Perfect Temperature Control 40W Variable Wattage Mini Box Mod VW Mod 510 Thread-28.87 and Free Shipping| GearBest.com

Oh, and this looks (maybe) stateside:

Eleaf iStick 40w Temp Control Mod Full Kit - $29.99!

 

[FishingBuffalo]

Not sure who will see this. I have one of these VF Mini's. I use the temp control exclusively. One day (after I dropped it) the temp went real wonky, temperamental, and intermittent actions. I just was about ready to send it back to supplier. I didn't and glad I did not:

I took the 2 top screws off and the top plate. The 510 connector has a small nut holding it to the top plate. It was loose. So, I tightened it up with a small pair of needle nose pliers,and the unit has been outstanding and I like it over my Heatvape (which I love).

Also I thought the light was squirly but actually helped me to clean up a cat hairball the other night without waking up the wife.

Hope this helps somebody.

 

[sofarsogood]

My mini update. I've had this device and used it exclusively for a couple months? I don't remember exactly when I got it. It's been fine. If there is some shortcoming somebody please tell me what it is.

I do have one gripe with temp control generally. The very low ohm coil means batteries don't last so long. I make the biggest nickel coils that will fit in my RDA's and get to .14 ohm. When that hits 500 degrees it's still a low .3 ohms. I believe I can make a titanium coil with 28 guage that will start at .8 ohms and it will reach about 1.6 ohms at 500 degrees. It seems to me this should be a lot more energy efficient setup. Has anyone tried this?

In the mean time I like the Kangxin mini. It's been flawless as far as I can tell.

 

[zoiDman]

My mini update. I've had this device and used it exclusively for a couple months? I don't remember exactly when I got it. It's been fine. If there is some shortcoming somebody please tell me what it is.

I do have one gripe with temp control generally. The very low ohm coil means batteries don't last so long. I make the biggest nickel coils that will fit in my RDA's and get to .14 ohm. When that hits 500 degrees it's still a low .3 ohms. I believe I can make a titanium coil with 28 guage that will start at .8 ohms and it will reach about 1.6 ohms at 500 degrees. It seems to me this should be a lot more energy efficient setup. Has anyone tried this?

In the mean time I like the Kangxin mini. It's been flawless as far as I can tell.

I don't have a good way to compare Battery life for Nickel vs. Titanium. Because I gave all my Nickel wire away.

But I would be Interested to hear if you see a Significant Difference between Nickel and Titanium.

 

[TheBloke]

My mini update. I've had this device and used it exclusively for a couple months? I don't remember exactly when I got it. It's been fine. If there is some shortcoming somebody please tell me what it is.

I do have one gripe with temp control generally. The very low ohm coil means batteries don't last so long. I make the biggest nickel coils that will fit in my RDA's and get to .14 ohm. When that hits 500 degrees it's still a low .3 ohms. I believe I can make a titanium coil with 28 guage that will start at .8 ohms and it will reach about 1.6 ohms at 500 degrees. It seems to me this should be a lot more energy efficient setup. Has anyone tried this?

In the mean time I like the Kangxin mini. It's been flawless as far as I can tell.

Higher the ohms, lower the power, and therefore yes the better the battery life.

I normally build Titanium to about 0.40Ω, I've never gone as high as 0.8Ω. Personally I wouldn't build artificially just to increase the ohms, but you could give it a go. Be aware that the stated maximum for TC on these mods is 1.0Ω, and while your base is under that your heated resistance is over it. Theoretically it should work - we know it does on the authentic DNA 40. Just making you aware that you're going into somewhat uncharted territory.

Titanium is a far better wire than Ni200 anyway, and its higher resistance is a key factor in that. Ultra low resistance uses more power as you've seen, it's also less accurate for TC, and it greatly reduces flexibility in building.

I wrote this post the other day summarising comparisons between various TC wires.

 

[KenD]

Higher the ohms, lower the power, and therefore yes the better the battery life.

It doesn't work quite like that with regulated mods. Wattage is what counts. Lower resistance means lower voltage at a certain wattage, and higher resistance means higher voltage at the same wattage. Check steam-engine for amp draw at the battery (chose vw regulated mod). You'll notice that resistance doesn't affect the amp draw at the battery at all. Wattage does, and battery charge (lower charge = higher amp draw, the opposite of what you get with mech mods).

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[TheBloke]

It doesn't work quite like that with regulated mods. Wattage is what counts. Lower resistance means lower voltage at a certain wattage, and higher resistance means higher voltage at the same wattage. Check steam-engine for amp draw at the battery (chose vw regulated mod). You'll notice that resistance doesn't affect the amp draw at the battery at all. Wattage does, and battery charge (lower charge = higher amp draw, the opposite of what you get with mech mods).

Yeah, but with a higher resistance, a lower wattage is required to achieve a given amount of heat, surely?

With TC what we care about is target temperature

So let's say we have a 1.0Ω stretch of wire and a 0.1Ω stretch of wire. The 1.0Ω stretch of wire can be heated to 250°C in 1 second using, let's say, 20W. The 0.10Ω stretch of wire will require, let's say, 50W to achieve the same temperature in the same time.

I'm just making up the individual numbers, but that is surely the principle?

So although yes if you match the watts between two resistances, it's the same power (by definition with ohms law), the point is that with higher resistance you use proportionately less power to heat a given mass of wire to a given temperature in a given amount of time.

No?

 

[KenD]

Yeah, but with a higher resistance, a lower wattage is required to achieve a given amount of heat, surely?

With TC what we care about is target temperature

So let's say we have a 1.0Ω stretch of wire and a 0.1Ω stretch of wire. The 1.0Ω stretch of wire can be heated to 250°C in 1 second using, let's say, 20W. The 0.10Ω stretch of wire will require, let's say, 50W to achieve the same temperature in the same time.

I'm just making up the individual numbers, but that is surely the principle?

So although yes if you match the watts between two resistances, it's the same power (by definition with ohms law), the point is that with higher resistance you use proportionately less power to heat a given mass of wire to a given temperature in a given amount of time.

No?

That would depend on the wire gauge. Lower resistance coils commonly use heavier gauge wire and that's why they need more power to heat up. Using the same gauge, a .1 ohm strech of wire has a lot less material than a 1 ohm strech of the same wire, and therefore the .1 ohm coil will heat up faster.

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[TheBloke]

That would depend on the wire gauge. Lower resistance coils commonly use heavier gauge wire and that's why they need more power to heat up. Using the same gauge, a .1 ohm strech of wire has a lot less material than a 1 ohm strech of the same wire, and therefore the .1 ohm coil will heat up faster.

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Right, but we're not comparing the same wire - we're comparing two different wires, to make the point that higher resistance wires are better than lower resistance wires because they use less power/battery (amongst other benefits).

• 8 x 3mm wraps of 28G Ni200 will be 0.115Ω
• 8 x 3mm wraps of 28G Titanium will be 0.561Ω

For the same coil, the Titanium uses less power to achieve and maintain a given temperature.

 

[TheBloke]

And something I didn't even realise, it appears that the Ni200 coil in the above example also has double the mass of Titanium - so it's an even greater benefit!

According to Wire Wizard, the mass of the 8x3mm 28G Ni200 coil is 69.49 mg, compared to the mass of the equivalent Titanium coil being 34.63 mg.

Apparently Titanium is a lot less dense - 4.43 g/ccm compared to 8.89g/ccm of Ni200.

Double the benefit!

 

[TheBloke]

Which appears to be a benefit unique to Titanium - the mass of Stainless Steel 317 and Resistherm NiFe30 are all very similar to Ni200 (though still a little lower); so they still have the resistance benefit, but not also the huge mass benefit.

Titanium is the exception, at approximately half the mass of the others.

So it seems Titanium is a clear winner for power/battery considerations.

 

[KenD]

Right, but we're not comparing the same wire - we're comparing two different wires, to make the point that higher resistance wires are better than lower resistance wires because they use less power/battery (amongst other benefits).

• 8 x 3mm wraps of 28G Ni200 will be 0.115Ω
• 8 x 3mm wraps of 28G Titanium will be 0.561Ω

For the same coil, the Titanium uses less power to achieve and maintain a given temperature.

I don't think it's as easy as comparing the weight of two different wires. Instead we should look at the thermal properties of the different materials (something I have absolutely no expertise in).

But your example above doesn't work. A .1 ohm 28 ga titanium coil would use a lot less wire than a .1 ohm 28 ga nickel coil and therefore heat up faster. However, if disregarding the thermal properties, 8 x3 mm wraps of ti1 will heat up the same as 8 x3 mm of ni200.

So, sure there will be differences due to the properties of the materials, but that has really nothing to do with the resistance.

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[TheBloke]

I don't think it's as easy as comparing the weight of two different wires. Instead we should look at the thermal properties of the different materials (something I have absolutely no expertise in).

But your example above doesn't work. A .1 ohm 28 ga titanium coil would use a lot less wire than a .1 ohm 28 ga nickel coil and therefore heat up faster. However, if disregarding the thermal properties, 8 x3 mm wraps of ti1 will heat up the same as 8 x3 mm of ni200.

So, sure there will be differences due to the properties of the materials, but that has really nothing to do with the resistance.

But we are very much not comparing .1 of Titanium to .1 of Ni200 - people don't (or shouldn't) build to a resistance, they build a given coil that works in a given atomizer!

That's the whole point - that a given coil will be of a higher resistance of Titanium than it is of Ni200, which is the benefit.

We're comparing a given coil size. In my case, my preferred coil size for vapour production, that fits in my atomizers, is 8 x 3mm wraps of 26G

Of Titanium, such a coil will be 0.368Ω. Of Ni200, it is 0.075Ω

The following is from Wire Wizard : Ni200 vs Titanium, both 8 wraps x 3mm of 26G, 5mm leg length:

The coils are of identical length, surface area and volume. The resistance is much lower on the Ni200 coil. Therefore the power setting on the mod will be much higher for the Ni200, because its resistance is far lower. (I believe this might be what the Current per Volt measurement is showing, 13.31A for the Ni200 coil vs 2.72A for the Titanium?)

The mass of the Ni200 coil is also much higher, but you're right that we don't know whether mass alone is the only factor between different wires so let's ignore that for now. The resistance difference alone is enough to make a difference in power consumption.


PS. It's not just me saying this. From Dicodes' Application Note For Temperature Controlled Vaping:

Unfortunately, often wires with a high coefficient, like Nickel, have very good electrical conductivity and therefore have several drawbacks in their usage: - With a normal length windings (coils), the resistance will be very low (<0.2 Ohm). This induces high operation currents and thus reducing the overall efficiency (battery discharge time) and increasing the susceptibility to contact resistances to the atomizer and other contacts in the system.

 

[sofarsogood]

Another way to compare the "density" of different materials is "specific gravity". The specific gravity of water is zero. Things that float on water have a specific gravity less than 0. Things that don't float in water have a specific gravity higher than zero. Materials with lower specific gravity will begin radiating heat sooner rather than absorbing it. Titanium has a lower specific gravity than nickel so, other things being equal it might radiate heat sooner than nickel.

 

[KenD]

But we are very much not comparing .1 of Titanium to .1 of Ni200 - people don't (or shouldn't) build to a resistance, they build a given coil that works in a given atomizer!

That's the whole point - that a given coil will be of a higher resistance of Titanium than it is of Ni200, which is the benefit.

We're comparing a given coil size. In my case, my preferred coil size for vapour production, that fits in my atomizers, is 8 x 3mm wraps of 26G

Of Titanium, such a coil will be 0.368Ω. Of Ni200, it is 0.075Ω

The following is from Wire Wizard : Ni200 vs Titanium, both 8 wraps x 3mm of 26G, 5mm leg length:

View attachment 486576 View attachment 486577


The coils are of identical length, surface area and volume. The resistance is much lower on the Ni200 coil. Therefore the power setting on the mod will be much higher for the Ni200, because its resistance is far lower. (I believe this might be what the Current per Volt measurement is showing, 13.31A for the Ni200 coil vs 2.72A for the Titanium?)

The mass of the Ni200 coil is also much higher, but you're right that we don't know whether mass alone is the only factor between different wires so let's ignore that for now. The resistance difference alone is enough to make a difference in power consumption.


PS. It's not just me saying this. From Dicodes' Application Note For Temperature Controlled Vaping:

Unfortunately, often wires with a high coefficient, like Nickel, have very good electrical conductivity and therefore have several drawbacks in their usage: - With a normal length windings (coils), the resistance will be very low (<0.2 Ohm). This induces high operation currents and thus reducing the overall efficiency (battery discharge time) and increasing the susceptibility to contact resistances to the atomizer and other contacts in the system.

Why would the power setting be higher? Watts are watts, and a lower resistance ni200 coil doesn't generally require a higher watt or temperature setting than a similar built but higher resistance ti1 coil.

My objection was to the statement that a lower resistance coil will eat up more amps. On a regulated mod it does so only if the watts are set higher. That's really my only point.

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[TheBloke]

On a regulated mod it does so only if the watts are set higher. That's really my only point.

Sure. And on a TC mod, it will be set higher, by the mod, to reach a given temperature.

My objection was to the statement that a lower resistance coil will eat up more amps.

My original statement was "Higher the ohms, lower the power, and therefore yes the better the battery life." - I understand that that might have read like I meant it generically, but I didn't. I meant it in the context of TC with like-for-like coils.

New statement: "In TC, the higher the resistance of the wire type, the lower the power required to reach and maintain a specified target temperature assuming same coil size and wire gauge."

Why would the power setting be higher? Watts are watts, and a lower resistance ni200 coil doesn't generally require a higher watt or temperature setting than a similar built but higher resistance ti1 coil.

The temperature setting isn't higher - the temperature setting is the target. We want the same temperature in all scenarios. What we're talking about is how the target is reached. How much power is required to heat any given coil to a single target temperature, and then maintain it at that temperature.

Secondly, regarding "power setting", I probably shouldn't have said 'setting' in a TC context because it confuses things. The Ni200 coil requires more power. You may well set it to the same power setting, but the mod sends different, and greater amounts of power than it does to the higher resistance Titanium coil.

The power setting on the mod is only a maximum. Set to the max of, say, 40W, doesn't mean it's sending 40W, only that it won't send more than 40W.

Run my example Ni200 and Titanium coils at max 40W and the mod will send the full 40W to the Ni200 coil for a certain period of time. Into the Titanium coil it either won't send the full 40W at all, or will send it for a much briefer time before reducing the wattage.

So you could actually set the Titanium coil to a lower setting with little or no impact on the coil, especially on mods that have more than 40W power. In practice we don't, because why bother - it's all automatic. And many new TC mods don't even offer a wattage setting, it just operates on the basis of "get the coil to temp as fast as possible" and therefore sends as much power as necessary in all scenarios.

Overall the key point is that a given size/length of Ni200 coil has a much lower resistance than other TC wires and therefore is sent more power by the mod in order to reach/maintain a given target temperature. Ergo in practice it does use more battery.

 

[KenD]

Sure. And on a TC mod, it will be set higher, by the mod, to reach a given temperature.



My original statement was "Higher the ohms, lower the power, and therefore yes the better the battery life." - I understand that that might have read like I meant it generically, but I didn't. I meant it in the context of TC with like-for-like coils.

New statement: "In TC, the higher the resistance of the wire type, the lower the power required to reach and maintain a specified target temperature assuming same coil size and wire gauge."



The temperature setting isn't higher - the temperature setting is the target. We want the same temperature in all scenarios. What we're talking about is how the target is reached. How much power is required to heat any given coil to a single target temperature, and then maintain it at that temperature.

Secondly, regarding "power setting", I probably shouldn't have said 'setting' in a TC context because it confuses things. The Ni200 coil requires more power. You may well set it to the same power setting, but the mod sends different, and greater amounts of power than it does to the higher resistance Titanium coil.

The power setting on the mod is only a maximum. Set to the max of, say, 40W, doesn't mean it's sending 40W, only that it won't send more than 40W.

Run my example Ni200 and Titanium coils at max 40W and the mod will send the full 40W to the Ni200 coil for a certain period of time. Into the Titanium coil it either won't send the full 40W at all, or will send it for a much briefer time before reducing the wattage.

So you could actually set the Titanium coil to a lower setting with little or no impact on the coil, especially on mods that have more than 40W power. In practice we don't, because why bother - it's all automatic. And many new TC mods don't even offer a wattage setting, it just operates on the basis of "get the coil to temp as fast as possible" and therefore sends as much power as necessary in all scenarios.

Overall the key point is that a given size/length of Ni200 coil has a much lower resistance than other TC wires and therefore is sent more power by the mod in order to reach/maintain a given target temperature. Ergo in practice it does use more battery.

I don't know. With my mods and atties it doesn't really matter if I'm using a higher resistance 28 ga ti1 coil or a lower resistance 28 ga ni200 coil, as long as the builds are similar. I'm usually set at around 30w on my subtank minis and the same amount of power gets pushed to the coil. The ni200 coil isn't at a higher wattage longer than the ti1 coil. As long as the thermal properties and the coil mass are similar resistance, in itself, won't matter much. More coil mass requires more energy to heat up, but with nickel and titanium we're talking about differences in resistivity, not in coil mass. That's why I say that a .1 ohm nickel coil requires more current than a .1 ohm ti1 coil, because the former has more mass to heat up.

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[TheBloke]

Yeah fair enough. It's not something I've ever specifically tested, it just seems correct based on theory - and matches what Dicodes stated.

I'll see some time if I can see it in practice on the oscilloscope, it'd be interesting to have some data to use in the discussions on Ni200 vs Not Ni200.

 

[sofarsogood]

When I was satisfied with watts regulation a 1.5 ohm kanthal coil fired at 20 watts by an iStick 50w lasted for days. My Kangxin mini with a .15 ohm coil can consume the same total mah in a day. Most of the difference is the `10x lower coil resistance. I believe I can get a 28 guage .8 ohm titanium coil in my Tugboat rda and when it reaches 500 degrees the coil resistance should be around the same 1.5 ohm I got with kanthal and watts control and that should improve efficiency approaching the kanthal coil which starts at 1.5 ohm but doesn't increase as temp increases.

 

[vbreak]

So I was looking into getting the Kangxin 50W TC mod, but I was just wondering about longevity.
any of you that have been using it for a while now...have you had any issues?
does it seem like a device that will last?