Oxva Xlim Pro 2 DNA resistance issues.

[franticseven]

Gone to the opposite end of the scale from my usual table top  DNA 250C, RTDAs and RDAs.

The replay works, the 'anti-burn' works but all things considered the vapour and flavour is very disappointing.

I've never been great a fan of SS coils, but the 0.6ohm pod vapes like it's overpowered on boost but throttles off too soon for warm flavour.

I've plugged it into E-scribe, adjusted the wattage (18w), boost (zero) and warmth (7) until I get the flavour and temperature near enough.

So the Xlim registers a 0.6 ohm coil, my multi-meter reads 0.6 ohms but E-scribe reads the cold resistance from as low as 0.28 to an average of 0.33.

In developer mode, the preset for SS 0.6 ohm pod shows min resistance 0.27 to a max of 0.47.

Something can't be right?

Edited July 25 by franticseven

[Wayneo]

52 minutes ago, franticseven said:

The replay works, the 'anti-burn' works but all things considered the vapour and flavour is very disappointing.

I've never been great a fan of SS coils, but the 0.6ohm pod vapes like it's overpowered on boost but throttles off too soon for warm flavour.

I do the opposite. I leave my warmth at 2 or 3, and adjust my boost. I'm running my 0.6Ω pod right now at 15 watts. It's a pod. I know others running theirs at >23 watts. Boost has always been at most 1 second. Turn up your watts to the heat you like, and if you want more at the beginning add some boost.

52 minutes ago, franticseven said:

So the Xlim registers a 0.6 ohm coil, my multi-meter reads 0.6 ohms but E-scribe reads the cold resistance from as low as 0.28 to an average of 0.33.

If you look really carefully at that Ω symbol you'll notice a little squiggly through it. Those are equivalent ohms. They vape very similarly to the regular OXVA .6Ω pods.

52 minutes ago, franticseven said:

In developer mode, the preset for SS 0.6 ohm pod shows min resistance 0.27 to a max of 0.47.

That's 100% correct, as shown by Atomizer Analyzer. Did you really believe all these pods from all the manufacturers build to such exacting  standards.

How you get to the vape you enjoy is all up to you, and your device is working as expected.

[franticseven]

1 hour ago, Wayneo said:

It's a pod

I know, I wasn't expecting huge clouds or flavour thick enough to chew on, I bought it so that i could have a nicotine hit in the beer gardens without lugging around what my mate calls 'the hand-grenade'. I was hoping for a bit more than say a Kayfun with a 2mm coil that needed re-wicking

1 hour ago, Wayneo said:

I do the opposite. I leave my warmth at 2 or 3, and adjust my boost. I'm running my 0.6Ω pod right now at 15 watts.

yes, as I'm found out definitely a device where less is more👍

I'll try your setting.

50 minutes ago, Wayneo said:

That's 100% correct, as shown by Atomizer Analyzer. Did you really believe all these pods from all the manufacturers build to such exacting  standards.

um yeah,  the manufacturers have been making replacement coils for atomizers for over a decade with fairly reasonable accuracy.

i was kinda expecting a ~0.6 ohm pod 

 

52 minutes ago, Wayneo said:

If you look really carefully at that Ω symbol you'll notice a little squiggly through it. Those are equivalent ohms. They vape very similarly to the regular OXVA .6Ω pods.

spits out tea  'equivalent ohms' 

On the mod or the pod? I have my PC running through my TV..ain't no squiggle there.

[franticseven]

1 hour ago, Wayneo said:

I do the opposite. I leave my warmth at 2 or 3, and adjust my boost. I'm running my 0.6Ω pod right now at 15 watts

👍that works too

[Wayneo]

1 hour ago, franticseven said:

On the mod or the pod? I have my PC running through my TV..ain't no squiggle there.

On the mod. Right after the 0.6. Like the 1 o'clock position of the Ω symbol.

I double my nic from my regular mod, and 15 watts for me, gives me similar flavour.

[franticseven]

ah yes, found the 'equivalent ohms' icon in display colour schemes, tbh as I don't mess about with colour schemes or icons so I didn't look further. Just took it out of stealth mode..or not😁

I thought that was to denote SS / anti-burn. still 0.33 is not ~ 0.6,  thats like saying cat = dog because it has fur and four legs. 

thanks for the help sure I'll work it out as I go along, just trying to work out whether I need more 0.6s or should buy a selection 0.4/0.6 SS and a comparative 0.6 kanthal..Be a damned shame if the kanthal turns out to give a better vape.

BTW, made up my usual ADV in 50/50 dessert & strawberry..would perhaps benefit from more flavouring or just the wrong way to go?

I have two more steeping, @20% conc, an old bottle of Red Astaire and some key lime, 

Edited July 26 by franticseven
tw

[James Bellinger]

Here's a question. If you pull up your puffs in ECigStats, is it saying "dry coil"? What do you get as your Cold Ohms and Live Ohms near the end of your puff? I'm wondering if Live Ohms is 18% above Cold Ohms (dry coil) or 24% above Cold Ohms (wet coil)?

It determines wet coil by how much energy can go into it in a quick amount of time. If a juice is particularly bad at wicking, that could be the cause. I think John tested with 50/50 VG/PG, but I'm not sure. I will ask him next time I talk with him. If a juice has a ton of flavoring, enough to meaningfully affect the thermodynamics, I wonder if that could cause it.

Let me know about the Cold Ohms and Live Ohms. We have a ton of settings on these devices, so none of this is hopeless or set in stone.

 

Equivalent Ohms is something of a practical compromise.

People tend to associate the vape they get with a Kanthal coil of a particular resistance. But what they are really asking for is not an electrical resistance, but the thermodynamic properties associated with that electrical resistance.

The resistance of a Stainless coil, for the *same surface area and other thermodynamic properties*, is different from a Kanthal coil.

Thermodynamics doesn't care at all about electrical properties.

So, if manufactured correctly, a Stainless coil of "Equivalent Ohms" is meant to match the *thermodynamic properties* of a Kanthal coil of a particular resistance.

Now, one could do it another way, but otherwise "I want a vape similar to my 0.6 Ohm Kanthal coil, but with temperature protections" becomes a rather confusing question to answer.

 

Hope this helps.

 

God bless.

 

James

 

P.S. There are other practical compromises. See the "True RMS Power Mode" checkbox? That's a fun one.

If you want your watts setting to match your expectation on every PWM pod device we saw, keep it unchecked. This is "PWM Power Mode".

If you want your watts setting to match thermodynamics (and non-PWM devices), check that checkbox! This is "True RMS Power Mode".

(Actually, we did do better than other PWM pod devices when in "PWM Power Mode". See "Simulated Battery Voltage"? We make the true thermodynamic watts setpoint stable with battery voltage and battery voltage drop. The way most devices do it, this isn't true. Read on if you care about the math.)

It turns out all of the PWM pod devices determine their duty by P=Vpod^2/R, so Vpod=sqrt(P*R), from which they conclude PWM=Vpod/Vbat=sqrt(P*R)/Vbat.

A multimeter will back them up in this. (Mostly. There's also a huge battery voltage drop when firing on PWM devices.) The voltage is correct!

Unfortunately, this is wrong.

A multimeter will average the voltage over its sampling period. A PWM device is actually on/off.

So the *real* power on a PWM device, when fully on, is P=Vbat^2/R, because it is connecting the battery to the coil. So, at a particular PWM duty cycle (0-1), you get P=(Vbat^2/R)*PWM, or PWM=P*R/Vbat^2.

What's humorous about this is, when you measure with a multimeter, you're going to see the *averaged* voltage Vpod=PWM*Vbat=Psetting*R/Vbat. You're going to say "Let's use Ohm's Law", Pcalculated=V^2/R, and apply it to that averaged voltage, to get Pcalculated=Psetting^2*R^2/(Vbat^2*R)=Psetting*(Psetting*R/Vbat^2).

See? The multimeter will tell you that it's wrong, when it's thermodynamically correct. You can't average voltage and then do that calculation on a PWM device. The factor by which it's off is how wrong the other calculation is.

What you can see from the equation is that the way other PWM pod devices calculate wattage is not only incorrect, but the real wattage will change as the battery drains, and in a way that is different depending on the coil resistance. Fun!

This is why the Oxva Pro 2 DNA has a "PWM Power Mode" Simulated Battery Voltage setting. We did better than the other devices by (1) matching the wattage you'd find on other PWM pod devices, *at near full battery*, while (2) using *correct* power control to make that stable over resistance and battery level.

We left both options in. We knew for "PWM Power Mode" that most users of pod devices would be surprised if, even if entirely correct, the wattage level they set felt different than other devices. We also knew for "True RMS Power Mode" that we have some folks who can appreciate an accurate and correct vape. 

 

[franticseven]

@James Bellinger

wow, I've never looked at Ecigstats in 10+ years that I've used DNAs.

I don't believe I've had a dry coil event 1200 odd puffs to got through, the Xlim registered a 'fill pod'..I remember it clearly but it wasn't empty. Pod in pod out.

Doesn't seem to 'remember' the replay setting every time it comes out of idle, no great inconvenience

Also had the device fail to wake up today, thought the battery had gone flat but it woke up when I plugged in the USB. Still at 87%. Must remember to remove the pod to prevent sampling from running it down? Same issue with Steamcrave 4S 250C which wasn't recomended to be updated ..guess what? drain got worse..

I actually bought a few packets of SS and just the one pack of Kanthal. Was almost satisfied with SS at 17-18w , really need replay for the SS too, puff,puff,puff .

Got that the wrong way around, now I've tried both materials I prefer the Kanthal, 0.6 ohms@17w better flavour. The SS coil is bland, strangled, Compare those ohms? The thermal dynamics aren't the same..🙃

Screenshot of change over from 0.6ohm stainless pod &  first use of 0.6ohm Kanthal pod.

Edited Saturday at 09:02 PM by franticseven

[franticseven]

I don't doubt the science behind the boards set-up and operation, simple to say that the only regulated mods I have purchased for the last 10 years have been Evolve DNA equiped.

[franticseven]

Oh the juices, I've given the pods plenty of time to saturate, an hour+ and I'm not taking long puffs in an attempt to kid myself that it's comparable with a couple of framed staples in an RTDA @ 65w.

Nor have I vaped a pod to the point of needing replacement..I've seen the state of premade coils that people will endure 🤮 Kinda expect the usual..best flavour shortly before the cotton cries 'nuff' but don't think I've got there.

no fault of Evolve but  the only two I've had to replace are because the poxy bung has pushed in and the keyhole surgery has been unsucessful.

1) DIY dessert type flavouring 15% , 50/50 no other dilutant..actually 53% PG after nicitine adjustment. Much better with Kanthal

2) & 3)  T-Juice Red Astaire & a Ley Lime again 50/50 15% concentrate..up to 20% recomended. Made them as an experiment , mostly to see if I needed a more 'in your face ' juice.

[James Bellinger]

@franticseven, the device is set to turn off automatically if idle for 130,000 seconds (about a day and a half). It doesn't have to be awakened by USB -- holding the fire button for a few seconds wakes it up again.

The device has pretty decent idle current before it turns off, and so should not drain more than a few percent during this time, whether or not the pod is connected.

It should remember Replay coming out of idle but not turn-off, unless something has caused the pod to lose contact during that time.

It looks like your power output is actually higher on the Stainless coil. What does the trace look like in Device Monitor with the Stainless coil when puffing, Power and Live Ohms? It looks like you're rising about 21% on puffs, so it shouldn't be hitting a limit.

[franticseven]

yes I have the SS coil 1w higher, I'm trying to find a comparable sweet spot with two different juices.

Crazy yeah? But how many pods do I want to use to fine tune the device?  It's about £3 ( $4 ) a pod and I'm (£12) $16 in already because the pods are prone to swallowing the bungs.

todays  SS puffs, no boost, warm 4, I'm back to my first adjusted settings.

I'm gonna be on my ass if I keep puffing away looking at the screen🤣

zero boost zero warm

zero boost warm 4

 

Edited 15 hours ago by franticseven

[Wayneo]

Just popping in and out again, and apologies if you already realized this.

Boost works at the start of a puff.
Warmth is only activated if Replay is enabled. You really won't notice warmth unless you only activated Replay near the end of a session and allowed the coil to cool down.

[franticseven]

1 hour ago, Wayneo said:

Just popping in and out again, and apologies if you already realized this.

Boost works at the start of a puff.
Warmth is only activated if Replay is enabled. You really won't notice warmth unless you only activated Replay near the end of a session and allowed the coil to cool down.

No worries, appreciate the advice.just raises more questions.

boost is off; personal preference  it doesn't have to get hot ASAP, I've had no insane wish to sear my throat for a decade.

replay is currently off, so no TC until you activate replay? Or can't you control temp  via warmth on a scale of 0-10 before you vape? 

am i just being odd by trusting my puff/draw but relying on the board not to allow the coil to burn? Because PP..no boost, mid-warmth and no replay is about as acceptably 'middle of the road' as i have got. 👍👎 

without replay am I running SS in watts ? But with dry hit/fill pod in reserve

So if the issue may be setting replay 'warm'..surely thats the idea 'to replay', you have  a few puffs find your prefered sweet-spot and set replay.  Then once cooled down the repeated puffs ..aren't. Actually rather (and increasingly) weak and unsatisfying.

Now we've gone from questioning ohms to is replay actually working all of the time? is the replay 'confused' by live, warm and cold ohms?

Does replay need to be set every session but 'cold' ? 

[Wayneo]

Just to keep this succinct;

You're always getting dry hit protection and fill pod warnings, as long as you're using these SS pods. Replay or not.
You can hover over the 'warmth' term (escribe) for an official definition, but Replay must be enabled for it to do anything. Notice the default is 1.
You can enable Replay whenever you want, and it's not working until you do.

[James Bellinger]

That's only 19% over cold, so it shouldn't be hitting any limits. I see you're using 1W extra -- do you find the coils taste about the same at that level? You still have headroom to increase it if need be.

 

[James Bellinger]

By any chance, is there a contact pin on your Oxva that is stuck down? We saw that once -- it caused poor electrical contact --  and because the electrical current is higher on the Stainless pods, the power losses from poor electrical contact are higher.