It'll be quickly apparent if it has the issue. I wouldn't worry too much about it, if you get it, you'll be taken care of quickly. I hear VF may be shipping advance replacements.
My thoughts and issues with the DNA40
- Thread starter rusirius
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It'll be quickly apparent if it has the issue. I wouldn't worry too much about it, if you get it, you'll be taken care of quickly. I hear VF may be shipping advance replacements.
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No issues with the board in my feeder.
It currently has a 24 gauge Titanium coil on it:
Yes, it runs in temperature mode, although due to the different coefficient, temperatures obviously aren't what the board thinks they are. I stated with the lowest setting, 200F. No vapor at all. In fact, I got no vapor until I got to above an indicated 300. An indicated 350 provides a good vape, comparable, I think to nickel at 450.
No issues with the board in my feeder.
It currently has a 24 gauge Titanium coil on it:
Yes, it runs in temperature mode, although due to the different coefficient, temperatures obviously aren't what the board thinks they are. I stated with the lowest setting, 200F. No vapor at all. In fact, I got no vapor until I got to above an indicated 300. An indicated 350 provides a good vape, comparable, I think to nickel at 450.
Subscribed.
No issues with the board in my feeder.
It currently has a 24 gauge Titanium coil on it:
Yes, it runs in temperature mode, although due to the different coefficient, temperatures obviously aren't what the board thinks they are. I stated with the lowest setting, 200F. No vapor at all. In fact, I got no vapor until I got to above an indicated 300. An indicated 350 provides a good vape, comparable, I think to nickel at 450.
I have some various gauges of titanium I could try. Has anybody come up with a ballpark temperature conversion formula or are we still feeling it out?
How many various? All I could ever find in pure Ti was 24 and 30. If you're talking about a certain Greek vendor's wire, that's an alloy and has noticeably different properties than pure Ti does.
Ah, yes. In my case it would be the mystery alloy.
I'll plop it on and see what happens, might not even go into temperature protection.I've been happy with nickel 28 and 30, really want to get some 32. I do have plenty of the Ti alloy to play with also, if it gets me anywhere.
Ok everyone, here's my latest update.... I've done some pretty extensive testing at this point and think I've narrowed it down pretty well.
As Dr G stated, it does appear that my board suffers the screen glitch issue, despite being one that had apparently been "corrected" (grey epoxy/silicon of some sort under the ribbon cable).
At first I thought it wasn't JUST the screen glitch because of the other issues I've been experiencing, but I've come to realize what I believe to be is causing all of the issues.
When the screen glitch happens, and the display locked up I've noticed that sometimes it "drops out of temperature protection mode". What I've come to the conclusion of now, is that most times it's not dropping out, but... When it glitches it appears to immediately do a "reset" on the atty. It doesn't prompt or ask, it just does it... And depending on WHERE during the firing it happens, it's anyone's guess as to what temp the coil is at that point...
I'm going to throw some wild numbers out here... These aren't based on any accuracy, I'm just using them purely for demonstration purposes...
Let's say I have a .15 build. And let's say the resistance increases .1 ohm for every 100 degrees in temp....
If the coil has JUST began to fire, and has only raised 50 degrees in temp when the screen glitches, it resets the atty to .20 ohm.... So now it will fire 50 degrees higher than my set temp... So my 460 degree setting becomes 510 degrees....
But what seems to happen MOST often is that it glitches much later into the fire... So let's say my build has reached 400 degrees.... Now the screen glitches and resets... Now it thinks the base resistances is .55... Meaning that the next time I fire it it's going to let it hit 850 degrees....
Again those aren't real numbers... just demonstrating what's happening...
I spoke to another person who was having this issue, and they believed this "reset" of the base resistance was only happening after the unit sat idle and was powered back up. In my case it appears to happen immediately when the glitch happens... I'm guessing that when the screen glitches out, it's shorting the power supply and sagging to a level where it essentially resets itself without actually doing a true reboot. If that makes sense... MCUs can do all sorts of things when there is noise on the power rail or when voltage dips below it's minimum levels, so who knows what else it might do when this happens... Which explains some of the weird things I've seen.
My solution in the mean time has been to keep the unit in stealth mode. By doing so it never glitches... hence it never resets the base resistance, and therefore continues to function perfectly normal.
Evolv has sent me an RMA, so at this point here's where I'm at. I've ordered a second board. When it arrives I'm going to swap out this one with that one. Then I'm going to exam the old one. I have some surface mount soldering equipment, so I may just pull the ribbon off, insulate the vias, and replace it myself to see if that fixes the issue. Otherwise I may just send it back and have it replaced. Does anyone know how long it typically takes them to replace a board?
As Dr G stated, it does appear that my board suffers the screen glitch issue, despite being one that had apparently been "corrected" (grey epoxy/silicon of some sort under the ribbon cable).
At first I thought it wasn't JUST the screen glitch because of the other issues I've been experiencing, but I've come to realize what I believe to be is causing all of the issues.
When the screen glitch happens, and the display locked up I've noticed that sometimes it "drops out of temperature protection mode". What I've come to the conclusion of now, is that most times it's not dropping out, but... When it glitches it appears to immediately do a "reset" on the atty. It doesn't prompt or ask, it just does it... And depending on WHERE during the firing it happens, it's anyone's guess as to what temp the coil is at that point...
I'm going to throw some wild numbers out here... These aren't based on any accuracy, I'm just using them purely for demonstration purposes...
Let's say I have a .15 build. And let's say the resistance increases .1 ohm for every 100 degrees in temp....
If the coil has JUST began to fire, and has only raised 50 degrees in temp when the screen glitches, it resets the atty to .20 ohm.... So now it will fire 50 degrees higher than my set temp... So my 460 degree setting becomes 510 degrees....
But what seems to happen MOST often is that it glitches much later into the fire... So let's say my build has reached 400 degrees.... Now the screen glitches and resets... Now it thinks the base resistances is .55... Meaning that the next time I fire it it's going to let it hit 850 degrees....
Again those aren't real numbers... just demonstrating what's happening...
I spoke to another person who was having this issue, and they believed this "reset" of the base resistance was only happening after the unit sat idle and was powered back up. In my case it appears to happen immediately when the glitch happens... I'm guessing that when the screen glitches out, it's shorting the power supply and sagging to a level where it essentially resets itself without actually doing a true reboot. If that makes sense... MCUs can do all sorts of things when there is noise on the power rail or when voltage dips below it's minimum levels, so who knows what else it might do when this happens... Which explains some of the weird things I've seen.
My solution in the mean time has been to keep the unit in stealth mode. By doing so it never glitches... hence it never resets the base resistance, and therefore continues to function perfectly normal.
Evolv has sent me an RMA, so at this point here's where I'm at. I've ordered a second board. When it arrives I'm going to swap out this one with that one. Then I'm going to exam the old one. I have some surface mount soldering equipment, so I may just pull the ribbon off, insulate the vias, and replace it myself to see if that fixes the issue. Otherwise I may just send it back and have it replaced. Does anyone know how long it typically takes them to replace a board?
So I've had the exact same problems as OP. The screen off tip seems to work perfectly so far! Thank you!
My resistance changes about 10% and unlike rusirius it seemed to me to change on reset when the atty is still slightly hot. Even 10% off (0.01 ohm) seems to throw the TC off so I just set power to 20 watts so it vapes "as usual". I haven't had a dry hit yet not even with dual coil and actually have a hard time telling when it's time to drip lol. I also didn't have the chip drop out of TC mode / show voltage except on my very first test with a brutally tortured test coil. I have the suspicion that the "switch to voltage mode" issues are related to connectivity issues where an additional resistance changes the temperature response curve drastically.
I've only used non contact / spaced coils so far. I have the suspicion that contact coils are no good or at least unreliable for TC, because the nickel doesn't create an isolating oxide layer. So you have shorts lowering the resistance, shifting during heat / cooldown and generally messing the temperature control. Maybe it works perfectly, I'm just suspicious / don't understand and want to avoid hotspot issues. The easiest way to make them is with a M3 stainless steel screw that also fits perfectly in my coil jig.
I've used dual coils on my magma and it turns out the connectivity on the magma with through post holes was fine with AWG30 wire. I tightened it a few times but it turned out my resistance shift is related to the reset with warm coil. I love your suggestion and also thought if it might be possible to put some kind of thin stainless steel ribbon inside of the post hole to create a more stable connectivity.
Hope my new DNA40 arrives today and will also rip out my faulty chip and inspect / insulate it again, but I'm almost convinced it must be a different problem that those vias. Except for the screen issue I'm very happy with the DNA40.
About work hardening the wire, haven't tried it yet but someone suggested this method from a rip tripper video. I think this straightens and tempers the wire at the same time.
I think I'm actually going to stick with fahrenheit. The boiling points of juices are somewhat "arcane" anyway and not really related to any other real life temperatures, so what the hell... might as well roll with it
I've managed to buy some titanium wire (grade 2, almost pure) from zivipf.com (europe) and going to test it out. I do think many issues are related to 510 / post connectivity issues and minor resistance changes creating huge differences in temperature sensing. So higher resistance builds will help with those "everyday" problems. Although I don't think I have connectivity problems.
I've made an attempt to create a temp table for titanium wire and what to set the temp to. Someone will have to check the math though, I'm not quite sure about it. Also a definite temperature coefficient of resistance for titanium would be good. IF my math and temp coefficient works out, a ballpark figure would be to set temp to about 65% of what you would set for nickel. Maybe there is a way to calibrate it with the boiling point of water.
Sounds interesting, do you have a source for this?
My resistance changes about 10% and unlike rusirius it seemed to me to change on reset when the atty is still slightly hot. Even 10% off (0.01 ohm) seems to throw the TC off so I just set power to 20 watts so it vapes "as usual". I haven't had a dry hit yet not even with dual coil and actually have a hard time telling when it's time to drip lol. I also didn't have the chip drop out of TC mode / show voltage except on my very first test with a brutally tortured test coil. I have the suspicion that the "switch to voltage mode" issues are related to connectivity issues where an additional resistance changes the temperature response curve drastically.
I've only used non contact / spaced coils so far. I have the suspicion that contact coils are no good or at least unreliable for TC, because the nickel doesn't create an isolating oxide layer. So you have shorts lowering the resistance, shifting during heat / cooldown and generally messing the temperature control. Maybe it works perfectly, I'm just suspicious / don't understand and want to avoid hotspot issues. The easiest way to make them is with a M3 stainless steel screw that also fits perfectly in my coil jig.
I've used dual coils on my magma and it turns out the connectivity on the magma with through post holes was fine with AWG30 wire. I tightened it a few times but it turned out my resistance shift is related to the reset with warm coil. I love your suggestion and also thought if it might be possible to put some kind of thin stainless steel ribbon inside of the post hole to create a more stable connectivity.
Hope my new DNA40 arrives today and will also rip out my faulty chip and inspect / insulate it again, but I'm almost convinced it must be a different problem that those vias. Except for the screen issue I'm very happy with the DNA40.
About work hardening the wire, haven't tried it yet but someone suggested this method from a rip tripper video. I think this straightens and tempers the wire at the same time.
I think I'm actually going to stick with fahrenheit. The boiling points of juices are somewhat "arcane" anyway and not really related to any other real life temperatures, so what the hell... might as well roll with it
I've managed to buy some titanium wire (grade 2, almost pure) from zivipf.com (europe) and going to test it out. I do think many issues are related to 510 / post connectivity issues and minor resistance changes creating huge differences in temperature sensing. So higher resistance builds will help with those "everyday" problems. Although I don't think I have connectivity problems.
I've made an attempt to create a temp table for titanium wire and what to set the temp to. Someone will have to check the math though, I'm not quite sure about it. Also a definite temperature coefficient of resistance for titanium would be good. IF my math and temp coefficient works out, a ballpark figure would be to set temp to about 65% of what you would set for nickel. Maybe there is a way to calibrate it with the boiling point of water.
Sounds interesting, do you have a source for this?
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It does actually... It has a gray epoxy/silicon under the ribbon cable... If it is the same issue then either it didn't insulate well enough, or perhaps got pushed down too far... Or perhaps they did it as an after thought to the boards that were already constructed and maybe it got a trace of solder attached to the via during assembly that the silicon/epoxy wouldn't fix...
I'll have to try using a drill to straighten it... Another poster suggested that as well... I just built a dual coil in my atomic using 30awg that I hardened by simply holding it in pliars on one end and forcing a "z-bend" through it about 20 times using a tissue in my hand. The results were MUCH MUCH better... The coils were much more managable and didn't take any longer to balance out than standard kanthal... I also didn't have a problem with them in the posts. It definitely makes a big difference.
So yeah I did the straightening method... Much better...
I too had the screen glitch... I put more electrical tape liquid under the ribbon and haven't had an issue for the last 5 days... The only time mine switched to voltage mode was with my orchid, my center posi post screw in the 510 connector was really loose... Tightened that up and haven't had the issue for 4 days... Hope this help bc I love my 40 device
Sent from my iPhone using Tapatalk
I too had the screen glitch... I put more electrical tape liquid under the ribbon and haven't had an issue for the last 5 days... The only time mine switched to voltage mode was with my orchid, my center posi post screw in the 510 connector was really loose... Tightened that up and haven't had the issue for 4 days... Hope this help bc I love my 40 device
Sent from my iPhone using Tapatalk
Nice!
The thing to keep in mind is that temperature coefficient is not necessarily a fixed number; it can vary with temperature. The quoted/published number is usually around room temperature. To make matters even more complicated, the variation isn't necessarily linear.
My personal experience with just one 24 gauge Ti coil is that it barely began to produce vapor set to 300F, and we know that Ni200 makes plenty of vapor at 460F, which means the straight-line extrapolation in your spread sheet probably doesn't represent the what's happening in the real world.
I've got access to an FLIR i7 camera that I was hoping to use to get some good empirical data, but that's turning out more difficult than I thought it might be.
Maybe we should have a thread specifically for Ti on the DNA40 rather than jacking this one too far..?
Yeah I thought so too but this here says "The temperature dependence of conductors is to a great degree linear and can be described by the approximation below."
But I assume too it's really some kind of polynomial. The temperature coefficient for titanium I got from here and it said "Temperature coefficient @0-100C ( K-1 )" so of course this is just an approximation.
My only idea is to use the boiling point of water (100°C) to measure the temperature coefficient for our specific titanium wire. Or find the char point of organic cotton like from the reddit picture lol, that might be great for calibration haha.
Dunno if you can measure more precisely with the IR camera, you might have to take th heat emission value of the wire into account. I'm not a physicist.
Ideally evolv should publish these numbers, they probably already have them or have the equipment to adequately measure them. A simple accurate table like this would be great.
As a first approximation, why not use the boiling point of, say a 50/50 PG/VG mixture? 'Cause that's the area we're most interested it. At what set/indicated temperature does a wet coil start producing vapor?
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