Joyetech Evic VT 60 Watt

[TheBloke]

Wow Ok, 230-240°C is very high! That's the exact opposite of what I would expect. Even if it's only reading a little too high I'd expect burnt hits at such a high setting. If it was reading 0.02Ω too high then 240°C might be as high as 260°C in practice - I haven't run the numbers for Titanium yet.

Maybe then the dna is reading -0.04Ω and the VT is spot on

Edit: sorry I'm confusing myself, hang on..

No I was right the first time - 240°C is the opposite setting to the one I would expect for a mod with too-high resistance.

• Let's say the Titanium coil is 0.40Ω but the VT reads it as 0.42Ω.
• You've configured a 240°C limit.
• The coil of 0.40Ω when heated to 240°C will reach 0.708Ω, which would be read as 0.728Ω.
• The mod will calculate a 0.42Ω -> 0.728Ω rise as being 229°C, ie 11°C lower than configured
• Therefore when the coil is actually at 240°C, the mod thinks it's still got 11°C to go, so it will continue heating it - perhaps up to 250°C.

(The above assumes the wire has TCR 0.0035 - as we know Zivipf's wire is - and the mod also uses 0.0035 to calculate with.)

Even 240, let alone 250°C is more than enough to at least darkly singe dry Rayon. So if you've done a dry cotton test and don't have that, then the VT is not reading too high. Or perhaps the VT is calculating for a different TCR than your Titanium actually has But probably it's not reading too high.

So what's going on with the DNA 40 -> VT comparison I don't know. Reading too low is a very specific issue that has to be the chip - you can't remove resistance with poor wiring/connections. But the DNA40s aren't known to read low.

Anyway, thanks for helping me decide - I need a VT. I will order one now so I can test it. Wish I could get it without the stupid tank, but oh well!

 

[atroph]

....Most of the people with these devices stuck in their faces don't even realize how deadly they are at extremely low resistances. TC pushes batteries extremely hard, without knowledge of ohms law and how destructive these batteries can be if you don't respect them...a beginner can be in for a world of hurt. Beginning TC vaper is a lot different than a beginning vaper.

This isn't entirely true. The load on the battery should be well within specifications if the thing is engineered correctly. You also have to keep in mind that the load decreases once the coil heats up. By law if "R" goes up "I" goes down at the same "V". The info below is set to a static resistance and doesn't account for the temp change. I would consider this maximums that the mod would see as it wouldn't be at 60W for very long before it dropped the power down.

Power (W)          Resistance (Ω)    Current (A)   Voltage (V)
60                    0.12               22.36        2.68
55                    0.12               21.41        2.57
50                    0.12               20.41        2.45
45                    0.12               19.36        2.32
40                    0.12               18.26        2.19
35                    0.12               17.08        2.05
30                    0.12               15.81        1.90
25                    0.12               14.43        1.73
20                    0.12               12.91        1.55
15                    0.12               11.18        1.34
10                    0.12               9.13         1.10
5                     0.12               6.45         0.77
1                     0.12               2.89         0.35

 

[TheBloke]

Agree once again. But to give you an idea of the differences, the DNA40 has recommended wire gauges for their chip. If one mod maker uses 28ga wire and the other uses 30ga wire, their resistances will be different. Same chip, different wire gauges.

Yeah I agree there's lots of places for small inaccuracies to creep in. Though in the case of wire gauges, Evolv's specs are between 18 and 22 gauge and I believe that's been set exactly because of that, to limit static resistance.

I built my own ohm reader using a Fat Daddy v3 Shorty wired with 1.5mm (15G) copper into my DMM (via gold plated banana plugs), and the ohms were so low that it registered 0.00Ω when I shorted it (my DMM only displays two decimal places for Ω)

Now that's 15 Gauge, and yes a manufacturer could use up to 22G.. actually, let's find out! - it's quite an interesting point.

• This table shows Ω/m for different gauges of copper.
• 22G shows as 0.0530Ω / meter.
• So two leads needed for the 510, how long? Hmm, well mine are a total of 25cm (one 10cm, the other 15cm), which to me looks longer than the wiring in any mod I've opened.
• But let's say 25cm worst case, one quarter of a meter.
• So using the maximum specified wire for 510, 22G, and 25cm of it would give a static resistance in the mod's 510 of 0.01325Ω.

So yeah, point taken, a given mod could theoretically be +0.01Ω more than another mod with the same chip: if ModA uses only a few cm of 18G and ModB has lots of 22G, like in the above example.

I expect that's fairly common at the moment - Evolv put out those specs, but that's not to say each implementing manufacturer understood the importance. Evolv have published nothing on this subject publically (a pet peeve of mine), but we can hope they at least gave this sort of info to manufacturers.

Then there's all the other chip manufacturers coming out later, who again may or may not understand - or even care about - the implications fully.

So yeah I do take your point that these differences are to be expected. I would say 0.01Ω is the limit of tolerance - that's equal to about 30°F difference in Ni200, less in Titanium. It's when it gets more than that I'd class it a definite 'problem'. And I'd hope more and more manufacturers will start realising that even that is too much, and do all they can to measure accurately down to 0.001Ω - something that's quite achievable, both from on-chip accuracy and from knowing the exact Static Resistance of the mod setup and automatically accounting for it in the calculations.

I hope that's what Dicodes do - who claim 0.001Ω accuracy. They make both the chip and mod, so they have no excuse for not measuring the exact resistance of their 510 and wiring and automatically adjusting the read resistance by that amount.

 

[workman70]

So, my white Evic arrived today, already have the black one. Performs great, exactly as it should, but the screen is only about 60-70% as bright as my black one. Wonder if it's faulty or if there's a hidden adjustment.

 

[tchavei]

Wow Ok, 230-240°C is very high! That's the exact opposite of what I would expect. Even if it's only reading a little too high I'd expect burnt hits at such a high setting. If it was reading 0.02Ω too high then 240°C might be as high as 260°C in practice - I haven't run the numbers for Titanium yet.

Maybe then the DNA is reading -0.04Ω and the VT is spot on

Edit: sorry I'm confusing myself, hang on..

No I was right the first time - 240°C is the opposite setting to the one I would expect for a mod with too-high resistance.

• Let's say the Titanium coil is 0.40Ω but the VT reads it as 0.42Ω.
• You've configured a 240°C limit.
• The coil of 0.40Ω when heated to 240°C will reach 0.708Ω, which would be read as 0.728Ω.
• The mod will calculate a 0.42Ω -> 0.728Ω rise as being 229°C, ie 11°C lower than configured
• Therefore when the coil is actually at 240°C, the mod thinks it's still got 11°C to go, so it will continue heating it - perhaps up to 250°C.

(The above assumes the wire has TCR 0.0035 - as we know Zivipf's wire is - and the mod also uses 0.0035 to calculate with.)

Even 240, let alone 250°C is more than enough to at least darkly singe dry Rayon. So if you've done a dry cotton test and don't have that, then the VT is not reading too high. Or perhaps the VT is calculating for a different TCR than your Titanium actually has But probably it's not reading too high.

So what's going on with the DNA 40 -> VT comparison I don't know. Reading too low is a very specific issue that has to be the chip - you can't remove resistance with poor wiring/connections. But the DNA40s aren't known to read low.

Anyway, thanks for helping me decide - I need a VT. I will order one now so I can test it. Wish I could get it without the stupid tank, but oh well!

Well I don't know. I never thought of 230C being off (if it's reading correctly). I did however notice many people vaping with higher temps on the VT than the dna (500f isn't uncommon to read).

In my case, I can assure you that I pre test each build with a piece of wick to make sure it doesn't scorch. I hate dry hits and I'm distracted as hell. Once I figure the charring point, I reduce 5 or 10C and place the definitive wick. I have never pulled an used wick (some with 270ml use) that had any scorch mark and I'm known for sucking on an empty tank for 30 minutes before realising it's empty lol.

It's 3 am here but heck, now I'm curious. Going to rebuild my erlp from scratch. If it stays with a 0.04 offset, I rest my case.

The pre made joye head definitely reads 0.36 on the dna and is reading 0.39 on the VT right now. That's 0.03 diff.

Regards
Tony

Sent from my keyboard through my phone or something like that.

 

[workman70]

So, my white Evic arrived today, already have the black one. Performs great, exactly as it should, but the screen is only about 60-70% as bright as my black one. Wonder if it's faulty or if there's a hidden adjustment.

 

[TheBloke]

Well I don't know. I never thought of 230C being off (if it's reading correctly). I did however notice many people vaping with higher temps on the VT than the dna (500f isn't uncommon to read).

In my case, I can assure you that I pre test each build with a piece of wick to make sure it doesn't scorch. I hate dry hits and I'm distracted as hell. Once I figure the charring point, I reduce 5 or 10C and place the definitive wick. I have never pulled an used wick (some with 270ml use) that had any scorch mark and I'm known for sucking on an empty tank for 30 minutes before realising it's empty lol.

It's 3 am here but heck, now I'm curious. Going to rebuild my erlp from scratch. If it stays with a 0.04 offset, I rest my case.

The pre made joye head definitely reads 0.36 on the dna and is reading 0.39 on the VT right now. That's 0.03 diff.

Yeah I dunno. if it remains that high offset then perhaps your DNA 40 is way out of whack.

I was going to say maybe the VT is using a different coefficient than the Zivipf wire, but if it was it would surely use a higher TCR than 0.0035 - as we've seen in literature values of 38, 39, 42. Well, that makes it worse - using a too high TCR again contributes to over heating. EDIT: and that wouldn't apply to Joyetech's own heads of course..

Maybe they have the TCR too low! That would be nuts.

At this stage, who knows. As long as it's vaping well for you that's all that matters for now. I'll get one and see if I can get to the bottom of it..

PS. When you said 240°C, did you mean with your own Zivipf wire as well as the pre-built head(s)?

 

[USMCotaku]

and if he could read his face wouldn't be burnt lol

^^^^ this
The ni200 coil packages state what they are for..... Survival of the fittest

 

[atroph]

View attachment 465127

What are the firmware versions? I wonder if they tweaked the screen brightness between revisions to save a smidgen of battery life?

BTW 20 clicks gives you the firmware version.

 

[USMCotaku]

What are the firmware versions? I wonder if they tweaked the screen brightness between revisions to save a smidgen of battery life?

BTW 20 clicks gives you the firmware version.

I got a vendor sample....mine is version 1.10

 

[BNEAT]

Bad news: Mine is still dropping resistance by .02ohms for no apparent reason.

Every single topper I put on it has done this, even when locked. Let it sit for 10-15 minutes and boom, it takes 50-70 degrees more to get the same vape. Nickel, Titanium, single or dual, within recommended specs, under or over specs, same thing: .02+ drop in resistance (it seems to be a percentage of the base resistance) A .77ohm Ti coil actually dropped to .73ohms after Vaping perfectly for 3-4 hours.

BTW, my VT reads very close to the same resistance as my DNA40 Flask: usually <.01 difference ....until my little gremlin screws things up!

 

[BNEAT]

I guess it's really not a huge deal because it vapes fine when it does this, I just have to turn up the temp. It doesn't effect TC, either. When the tank is empty, TC still does it's job.

But, I have zero chance of knowing where my scorch point is...if that even matters.

 

[aldenf]

I hope that's what Dicodes do - who claim 0.001Ω accuracy. They make both the chip and mod, so they have no excuse for not measuring the exact resistance of their 510 and wiring and automatically adjusting the read resistance by that amount.

This is the only way this technology can be accurate; a completely closed system - mod, atomizer and wire - all coming from the same manufacturer that has calibrated the system to work together. I'm certainly not paying $500 for a proprietary, calibrated setup. The Dicodes can calibrate themselves within one one-thousandths of an ohm for all my atomizers and builds? The Dicodes can measure the varying temperature coefficients of different Ni200?

Currently, the chipsets don't self-compensate for the static resistance in the wiring from the chipset to the 510, nor the SR of the 510 (is it SS, Brass, Zinc alloy, spring-loaded, grounded through the mod, etc) nor the SR of different atomizers. Add to that the different temperature coefficients between various manufacturers' Ni200 and, indeed, between one manufacturer's different batches.

I think Tony has it right. Find the singe/char point on each new build and 10-20 deg less is your max temp. How do we accomplish this with pre-made coils? How do we expect half the vapers to figure it out? Titanium, stainless steel or other alloys may be stronger choices and allow for better accuracy.

The way we vape today, this technology will only ever be able to reasonably guesstimate the temperature of our coils. It will be upon us to determine the temperature limit on each individual build, based on a wick-burn test. I don't see better accuracy with this technology, in an open system, at an affordable price.

Just my .

 

[JeremyR]

View attachment 465127

The screen on the left looks proper. The other one is too bright.

 

[smokewell]

A reply from Joyetech about the burned wicks in wattage mode.

"In Power (wattage) mode, the first time the button is pressed after turning the device on, or fitting a new coil, the eVic VT runs through an atomizer test sequence that applies 25-40W initial power for a very short period (0.75 to 1.5 seconds depending on atomizer resistance). This test establishes whether the fitted atomizer is VT capable or not, and is performed once only after a new atomizer is fitted or the device is powered up. For all subsequent button presses the device goes straight to the correct voltage. We have tried to burn out a number of different coil designs by repeatedly removing and refitting atomizers to an eVic VT, and although there is the odd crackle as the atomizer quickly warms up, we have not managed to cause any burning of coils or wicks in any atomizer we have tried."

 

[mc8]

Ok, i hope its somehow my mistake, but i do have an little issue here..i wasn't sure about it before, but can't deny it anymore; so this morning i've had my mod set to 250'C. I was using it like that last night, and it was ok. But now, the vape was too hot for me, so i set it down to 210, and it was perfect. Well after an hour or so, i had to refill my tank, and now 250-260 is way colder vape than it was on 210 before. So i set it all the way up to 300, but all i got was a slightly burned hit, but still not a very hot vape?? Any ideas what happened here? I've noticed this before, but thought it was just me..today it was too obvious..btw. resistance never changed..

 

[mc8]

Ok, i hope its somehow my mistake, but i do have an little issue here..i wasn't sure about it before, but can't deny it anymore; so this morning i've had my mod set to 250'C. I was using it like that last night, and it was ok. But now, the vape was too hot for me, so i set it down to 210, and it was perfect. Well after an hour or so, i had to refill my tank, and now 250-260 is way colder vape than it was on 210 before. So i set it all the way up to 300, but all i got was a slightly burned hit, but still not a very hot vape?? Any ideas what happened here? I've noticed this before, but thought it was just me..today it was too obvious..btw. resistance never changed..

Pretty sure i found MY mistake. I'd delete my post, but it might help someone..so, after the refill, my tank flooded a bit, no big deal, i usually just blow the liquid out of the airflow holes. But when i took it apart there was a bit of the liquid left in the chamber and it makes sense that it had to have some effect on the connection.
Anyhow, all good now, back to being a happy vaper

 

[tchavei]

Yeah I dunno. if it remains that high offset then perhaps your DNA 40 is way out of whack.

I was going to say maybe the VT is using a different coefficient than the Zivipf wire, but if it was it would surely use a higher TCR than 0.0035 - as we've seen in literature values of 38, 39, 42. Well, that makes it worse - using a too high TCR again contributes to over heating. EDIT: and that wouldn't apply to Joyetech's own heads of course..

Maybe they have the TCR too low! That would be nuts.

At this stage, who knows. As long as it's vaping well for you that's all that matters for now. I'll get one and see if I can get to the bottom of it..

PS. When you said 240°C, did you mean with your own Zivipf wire as well as the pre-built head(s)?

Ok.

First thing first. I rebuilt the erlp last night with a spaced Ti coil, exactly the same as it was before. Put it on the VT and it read exactly the same: 0.37

I then put the atty on the dna and it read 0.36 wow, great!

This morning however, the dna refined and it now reads 0.34 lol

Wild theory... What if the higher current the VT seems to use to detect or refine the atty, is heating the wire just a few degrees which would be enough to read 0.03 higher than the dna?

Bloke, can you do the math what base temperature difference would be needed to go from 0.34 to 0.37? Is it marginal or significant?

Regards
Tony

Sent from my keyboard through my phone or something like that.

 

[TheBloke]

Hmmm well that's a very interesting theory, because that's exactly what the Dicodes does. With the Dicodes, you have to tell it to lock the resistance - similar principle to Set Resistance on a Yihi.

When you do that, it probes the coil with a small voltage, which I believe is a fixed amount such that it pushes different coil types up by varying amounts of temp. I haven't been able to see how much voltage applies because it's so fast it just causes my DMM screen to flash without displaying a figure.

But I can see it on the Dicodes screen - after probing the coil it shows the temperature as >20°C for a minute or so until it settles back to 20°C (the Dicodes assumes all coils are 20°C as it has no internal thermometer.) And more importantly I can see it on my external temperature sensor.

So could the Joyetech being doing the same? Absolutely. But if it is and isn't then refining away the difference, or simply showing the locked base resistance pre-probe, then that's.. odd. Of course it might simply be a display bug, and it locks at 0.34Ω, probes it up to 0.37Ω, displays 0.37Ω, but keeps using 0.34Ω.

I still don't understand why my Dicodes even does this probe. It's not mentioned in the manual or their separate Application Guide for Temp Control Vaping, which is otherwise rather detailed on their methods. I don't quite see what it achieves.

Anyway, assuming you put the coil on at 20°C, a 0.34Ω Titanium coil heated to 0.37°C has increased in temp to 45.21°C. That's in the right ballpark for where the Dicodes often heats coils to - at least Ni200, which can go as high as 60°C according to the temp probe. Titanium coils heat less. Not that that means anything, if the Joyetech is applying a small voltage it won't be exactly the same as the Dicodes.

So yeah, your theory is a good one. If correct it's still weird that it shows the post-probe resistance, but that could be a simple display bug.

When does the VT detect resistance? Do you have to press a button, or is it auto once you've screwed on the coil? If you have to press any button, then you could probably detect the voltage if you have any kind of DMM or volt meter. Connect it to the atty posts with crocodile clips and then press the button. On mine all I see is the scale at the bottom flash (the visual graph thing that's gives a bar-graph type display of the signal), I never see a figure, but before I got my temp probe it was enough to verify that there was a voltage being applied.

I was thinking of ordering a VT today but I might wait till early next week to get one a bit cheaper without the tank. As soon as I get it I'll be able to tell immediately on the temp probe.

 

[JeremyR]

Mod only express kits are available at multiple places.

Here's a couple.

Joyetech eVic-VT Express Kit - Eciggity

eVic-VT Battery Express Kit by JoyeTech $55.99