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thats not whats happening to me my resistance goes up when i go outside in the cold not down. mine went from .09 up to .29 and when i fired it it as it got warm burnt the pi** out of the juice
so far its happened three times go outside let mod sit pick it up go to vape on it get a nasty hot burnt hit resistance has risen all three times come back in the house let mod sit a few minutes go to fire it resistance is back at .09 where it started
Well the resistance can't go up in cold?
Unless there is a bad connection somewhere. Nickel increases resistance with heat and lowers with cold. The only way is that something is contracting causing a bad connection
Are you using a full contact or spaced coil?
Regards
Tony
Sent from my GT-I9195 through Tapatalk
Ok so reading all these awesome tests I think it's pretty safe to say:
- If you keep your atty on the mod in the cold and the base resistance goes UP then it's probably a connectivity issue caused by thermal contraction and you will get a too hot / burned vape.
- If you keep your atty on the mod in the cold and the base resistance does NOT CHANGE the vape should be consistent. This is how it should be ideally.
- If you keep your atty on the mod in the cold and the base resistance goes DOWN by 15% or so then your vape should be weaker.
An interesting question when and why does the chip readjust the base resistance? It would seem sensible that if the chip sees the temperature / resistance going down and the curve settling to a lower value than what it had (e.g. 0.16 ohm instead of 0.18 ohm in the cold) then it would use 0.16 ohm. This would lead to a weaker vape in cold weather. That is not ideal, it should just stick with the known base resistance at room temperature.
What would be a good feature would be that if the DNA40 measures the resistance it averages the values over maybe 5 seconds while showing "measuring resistance" and if the resistance fluctuates during that time it displays "connectivity problem?". So if you reset resistance you can shake the mod or something to make sure your connectivity is good. And after this it sticks to the initial base resistance no matter what and doesn't reduce it in cold weather.
It seems TIGwelder's DNA changes the base resistance after a while in the cold. I assume this happens without screen glitches or a "Evolve DNA40" message on reactivating the mod, correct? So I guess that is the current behavior of a functional chip. I also didn't know it rechecked resistance when pressing up button.
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tchavei, as far as I know all metals have a positive temperature coefficient things like carbon have a negative temperature coefficient.
That said, what if it knows when the coil goes below 68 degrees F it has to pour the coals to it. What better way than setting "the base temp" high which would cause everything to work the same but at higher power levels to compensate for the ambient cold air. Maybe???
The warm actually. I sat in the same spot during the tests today. No screen glitch, no evolv screen. The up or down button was just used as a way to wake it up without hitting the fire button so I could see the screen. The amount of time for it to change it was around 7 minutes.
Now I decided to see how far the resistance goes up when it hits the protection at 430F. I quickly unscrewed it and had it recheck
0.24 at 77F
0.43 just cooling from hitting near temp prot.
So a swing of 0.19
Let's say it was cooling off and was down to 350F as a wild guess
350 - 77 = 273F range
0.43 - 0.24 = 0.19 ohm change
273 / 19 = 14.36F per 0.01
0.02 ohm change approx 28F change at coil
Can anybody check that to the actual material properties?
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The wire, unlike us bags of flesh, doesn't care about the ambient temp change as much as we do. But if it adjusts the base and that swings the prot temp 20 degrees, we would notice that instantly.
So far I'm the only person that can duplicate this over and over. So take it's "possible" for it to happen.
Let's say it's 70 out. Cold water vs room temp water. Pretty noticable to us pallet and throat wise. Let's say the temp of the vape changes by that much. Again, noticable. On anything adjustable we'd probably say "need to adjust that a bit".
Still rattling this all around in my head
You can check it here it's a simple calculation. TemperatureAtTemp = 100% + 0.00641 * (Temp°C - 20°C). So resistance is a simple line depending on temperature. The actual chip might use a more accurate curve or something but it's largely linear.
At 450°F you should have 227% of the base resistance.
That's a pretty good point, it might simply be that if the dna delivers the correct temperature it just seems unreasonable HOT to someone in cold weather. Just like washing hands when coming from the outside in "normally hot" water. The rising resistance / dry hit in cold weather is a different issue though.
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Thanks, I'll check that out later
I think it's +121% since room is %100
I had a post written up and poof!
Basically I wrote that we need to think of this as a dynamic vv/vw device. Not just the temp stuff. Shifting the resistance, when it's so low to begin with, changes a lot I would imagine. If it is calculating output power for X wattage based on X ohms using X voltage..then a 0.02 change amplifies up higher. Maybe 20 watts really becomes 18 or 22
I think it's +121% since room is %100
I had a post written up and poof!
Basically I wrote that we need to think of this as a dynamic vv/vw device. Not just the temp stuff. Shifting the resistance, when it's so low to begin with, changes a lot I would imagine. If it is calculating output power for X wattage based on X ohms using X voltage..then a 0.02 change amplifies up higher. Maybe 20 watts really becomes 18 or 22
Interesting discussion!
I`m starting to wonder if certain atty designs are problematic. For example Kayfun types or Magma types or...
I`m starting to wonder if certain atty designs are problematic. For example Kayfun types or Magma types or...
there's some serious Bill Nye science going on in here. I camped over the weekend for 3 days. Lowest night was 23 degrees. My resistance went up from like 0.14 to something like 0.22+ (I was heavily intoxicated) but I never adjusted my settings and never got any dry hits. Both my devices worked great all weekend (Flask and Hana).
Also...I just snagged an rDNA 40 today. Love this chip.
Also...I just snagged an rDNA 40 today. Love this chip.
Maybe we should work towards a "knowledge base"? Something like this and anybody just copies, extends, changes and refines it as he sees fit. All the text itself would be creative commons share alike so any additions can be copied and used by anyone. Much stuff would need to be marked with "uncertain" or something until more testing is done or evolve chucks some more info.
DNA 40 knowledge base V0.000001 alpha
Features
Building coils
Tips and tricks / FAQ
How it works
Troubleshooting
Ok looks like this could be a bit of work so that's all for now lol
DNA 40 knowledge base V0.000001 alpha
Features
- Temperature protection
- Reverse battery protection
- Volting up and down the street
Building coils
- Nickel info
- Nickel safety info
- Contact and spaced coils: Do's and don't's
- Example build 1, 2 and 3
- Titanium wire info and builds
Tips and tricks / FAQ
- Vaping temperature limited vs watt limited with temp protection
- Breath control for beginners
- Don't drink and build
How it works
- Temperature coefficient vs resistance
- Base resistance
- Char temperature for cotton / rayon etc.
Troubleshooting
- Connectivity issues
- Post connectivity tips
- 510
- Cold weather issues
- Keep your threads clean
- Screen garble -> stealth mode workaround -> RMA the ....
Ok looks like this could be a bit of work so that's all for now lol
Well that sounds like connectivity issues due to contractin in the cold. The resistance should go down maybe 15% when it's cold not up by that much.
i still dont believe all of us who's resistance is rising in the cold is connectivity issues i dont think i could tighten my post screws any more than they are atm. seems that is the answer though to all fluctuating resistance problems. still seens like there is something else at work here but once my atty is empty i will recheck my post screws even though i used a triple twisted coil so i could get them tighter than i ever have with single strand ni200
what if the cold was say making a contact coil contract into a spaced coil would that cause the resistance to rise.but when it warms back up it becomes a contact coil again???
Exactly what I was thinking since nickel doesn't build up a good insulated layer as kanthal does. Heck, for some unknown reason most people don't hot pulse the ni200 coil in the first place. That could definitely explain the anti Natura resistance raise in cold environments. That's why I asked last night if we were talking about full contact coils in those particular cases
Regards
Tony
Sent from my GT-I9195 through Tapatalk
Indeed.
Just for fun, since I knew it was going to get very cold last night, before I went to bed I threw my mod and atty in the truck. It was running a big dripper with a .18 build.
When I got up this morning it was 27 degrees. I picked it up and fired it and the vape was perfect. Checked the resistance and it was spot on .18.
Now I've given this a lot of thought, and I think I've come up with a couple of fairly good explanations for why this is happening to some.
First let's understand how the DNA40 works in terms of it's power usage. We'll start from a completely fresh battery install.
The mod first fires, gives the logo on the screen and while it's doing so it reads the resistance and sets that as it's base resistance. This is what it uses for all temperature calculations. Now, you vape away happily and everything is perfect. Then you sit the mod down.
After a few seconds it dims the screen, then after 30 seconds or whatever it is, it turns off the screen. At this point the mod is still working exactly as normal, it just has the screen turned off. You pick it up again and fire it and everything works just fine.
Now you sit it down again. This time it dims, then turns off the screen. After 5 minutes of being idle it puts the MCU in a sleep state. Essentially it powers down. When you pick it up again and fire it, it re-reads the base resistance.
Now normally this works perfectly fine, because after 6 or 7 minutes the atty and board are at the same temp again. BUT....
I only ever ran one build using 28awg. It was also in my big dripper. The way the BD is designed, to get the coils down in front of the air holes you have to push them way down into the juice well after they are wicked. (The lip of the well is actually higher than the through holes on the posts.) Because of this the wick get's packed in pretty well around the coils. The problem I had with it was that if I fired it cold and used it it was great. If I was working on something though, set the mod down for 5 minutes or so, then picked it up and fired it again the vape would be considerably hotter. Sometimes to the point of burning if the wicks weren't really saturated.
What I determined was that it was due to the heat retention... In other words, because the wick (rayon) was packed in so tight around the coil, it was acting as a great insulator. That combined with the extra heat capacity of the 28awg meant that after 5 minutes the mod had cooled down, but the atty was still warm. So it would read the base resistance again after it's sleep, but this time it would read it one or two hundredths of an ohm higher, which allowed the temp of the coil to climb well past the temp displayed on the TP.
To resolve that issue, I just started using 30awg. As soon as I did the problem went away. Most likely because now when it re-reads the resistance the coils have had time to cool down more and are closer in temp to the board.
Now, one other thing to mention here. I've mentioned the several strange quirks I had with my first board which exhibited the screen glitch. One of those issues was that after a sleep cycle it seemed to take longer to re-read the resistance. In fact, it seemed to fire the coil BEFORE it read the resistance. In other words, if the mod was sitting in sleep and I picked it up, it seemed to apply power the moment the fire button was pressed, but then there was a "pause" before it read the resistance. So I would have what is described here happen. I'd pick it up in the morning for that first morning vape for example, and suddenly my .12 coil was reading as a .15 coil and I'd get a horrible dry burnt hit. While I was still using the bad board doing testing, how I got around this was to get into the habit of always tapping the button VERY quickly when I first picked it up. This allowed it to read the resistance without actually firing the coil. Then all would be well. Well, as well as it got with that quirky thing. Perhaps whatever shorting or whatever was causing the screen glitch was also causing a lag between firing and reading the initial resistance. I dunno, I'd have to see the code and have a much better understanding of the board to be able to speculate on why that was happening. All I know is the symptoms it produced and a fairly good understanding of why it was happening.
I'm probably going to catch some flak for this, but I'm still going to have to insist that the problems with the DNA40 are much wider spread than being let on. The fact that TheKiwi had what? 3 or 4 different mods that all had the screen glitch issue? That's either really high odds of getting a bad board, or some TRULY horrendous luck on his part. Couple that with the fact that Evolv has apparently been pretty inundated lately. In the beginning there were lots of reports of emails being responded to very quickly, people getting personal phone calls from Brandon, etc. Very shortly after it all seemed to change. I know my first email to them took almost two days for them to respond to (in the middle of the week) and when they did there was no communication at all. Just an attached RMA form that said to fill out the form and send it back and it would be replaced or repaired. No apology or explanation, despite the details and questions I asked in my email. No response to the questions at all. Just a "send it back". I also saw a post (not sure if it was here or somewhere else) where someone said they spoke to someone at Evolv and was told that they have been slammed trying to deal with the RMAs. I'm sorry, but it's not a few boards out there acting weird... It's a LOT of boards out there acting weird.
In consideration of that, think of this. With my first board, as flaky as it was and as badly as it glitched. If I ran a kanthal build (or turned TP off) and ran it at a low wattage setting (lets say 12 watts) the screen wouldn't glitch. Turn TP on and run the watts really low and it wouldn't glitch very often. Turn TP on and run 40W and it would glitch almost EVERY single time on the first fire. The point is, even for as bad as my board was, if I had run a kayfun at 12W who knows if I even would have noticed the glitch on the screen. Yet the other wonky behavior may have very well been there. If the board wasn't as bad, who knows, I might have been able to run 20W or 30W and never seen a screen glitch but still had other issues. Who knows.
It just makes me wonder about some of the strange things we see happening here. Yes, there are is doubt that some issues can be caused by poor connections or whatever, but I've seen far too many descriptions that go beyond that. Sometimes it's difficult to weed out, but some are pretty obvious. I mean even VF and Evolv set up a separate RMA form / agreement for dealing with JUST the glitched boards. Do you really think they'd do that if it were only a few out there? They would just handle them like any other RMA, not create a whole separate form just for that issue. I just honestly think it's a lot more widespread than is being let on and I think that's starting to show.
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