DNA75 Preheat doesnt work...

[inteks]

hi,

on my hotcig dx75 the preheatfunktion doesnt work 


to double check  i made a profile with temp at 230° and 10w and 75w preheat for 5sec. and it stays cold.  what is wrong?

thx
inteks

[giz_60]

Are you saying that it is not getting hot at all? Are you getting any messages on the screen? Can you post a screenshot of Device Monitor showing you firing the device?

[inteks]

no.no....i set this only for testing.


atm i use 50w 230° ignoring that the preheat is not working ... it's ok.

but i like to know why preheat not work.

ps: i will post a devicemonitor screen when i'm @ home

[giz_60]

What kind of wire/coils are you using?

[retird]

@inteks.... in your example...  " i made a profile with temp at 230° and 10w and 75w preheat for 5sec. and it stays cold.  what is wrong?"

What do you get when you keep the same settings except increase the wattage from 10 watts to say 30 or 40 watts?  

[giz_60]

Ok, I just set my DNA75 up like you had with the preheat & at 230°c,10w power, 75w preheat, my device was dropping out of TC & into power mode because at 10w power, the board is not seeing enough temperature rise...when I raised the power setting to 50w, it worked fine.

     

Edit:...looks like retird beat me to it while I was typing...

[inteks]

ok.
here are 3 screens with 10w 30w and 75w...

at 30w it looks like a "little" preheat. but its far away from configured 5sec. ! 

and it doenst reach the configured 230°C before it falls down...


     

[dwcraig1]

Try taking your temp way higher, it's by no means accurate when used this way

[inteks]

it is celsius 230°C more than enough 

[dwcraig1]

Did you try it, the numbers mean nothing as far as what the temp really is.
275 -280 C should do it.

[dwcraig1]

Just in case you need more ideas they can be found here:
https://forum.evolvapor.com/topic/65540-topic/

[retird]

From the 3 screenshots the preheat is working.  You can see that the wattage settings 10 watts doesn't get you to the set temp of 230, the 30 watts almost gets you to the set temp of 230 and thew wattage setting of 75 easily gets you to the set temp.  Preheat, as you know is the green lines on the graph....

As @giz_60 said earlier.... "because at 10w power, the board is not seeing enough temperature rise".....

[inteks]

yes on 2. screen it looks like preheat is working. but why does it stop after a second if it doesnt reach the configured temp?

the wattage falls down at 200°C instead of 230°C ?!?!

[giz_60]

Battery sag?...what is your cell soft cutoff set for in the 'Mod' tab?

[giz_60]

Looks like the battery sag is kicking off the preheat & when the voltage rises, its firing at the set wattage...

[retird]

All I can say from my experience is that "tweaking" the temp, watts, preheat, punch, and duration for the best vape is all configurable.  Configure it to the levels you require. Battery sag also plays a more pronounced effect into the soup with a single battery device.  Hang in there and you will get it like you want it....  

[Wayneo]

I don't think it's battery sag in this case. Your mod is working as designed. When you have your punch set at 11, the preheat works until you're within 10F of your set temperature and then stops. Yours is set at 5. So the 'preheat' cuts out way before that. Increase your punch to 11 and you'll see. 

Then, watch what is actually required to fire that coil and adjust lower if you wish, or let the board do it for ya.

[inteks]

  Wayneo said:

...the preheat works until you're within 10F of your set temperature and then stops...

Expand  

Maybe thats the problem. 10F and 10C are not the same. If perheat stops at 10Celsius before temp its to low. I tryed with punch 11 but it still stops perheat to early.

[Wayneo]

@inteks "...10F and 10C are not the same" gotcha. Actually there's no temp monitor at all, and it doesn't matter F or C. What we're really talking is coil resistance change (to prove TC, and not drop out), then resistance value based on the wire profile/curve/TCR value (that matches what we would call a set temperature).

The mod is trying to get to your 'set' temp, without going over. As it's ramping up (on it's way to 75) and watching that coil resistance value change, the mod knows what power it needs to hit and maintain the desired/required coil resistance (basically your temp), so it'll drop power to try not go over, then blip that power back up to hit super close temp, then another drop .... down the power required to maintain the set temp. 

Some will notice the 'Karloz spike' usually on the first vape of a cold coil somewhere in the area of 2 to 5C.

Can you do us 2 more screen shots, of the profile settings like you did before, along with a device monitor shot. (I personally would use 2 different profiles setup, independantly to make testing quicker, then an easier change between the two)

Take a preliminary vape to warm the coil.
screen shot 1. Preheat set 75, Punch 0 or 1.

Take a preliminary vape to warm the coil.
screen shot 2. Preheat set 75, Punch at 11.

PS. IIRC you mentioned the coil was somewhere around ~.2 ohms. Can you describe it for us. Is it 1 or 2 coils? Is it a thin wire, or claptionized coil etc.? Spaced?

[Wayneo]

Just did this to match the text above. That red line is power, notice the ramp, then the blip as I described. See how the green (temp) line matches with the blue straight resistance line. 
Bottom shows in seconds.

 

[dwcraig1]

Karloz spike.......LOL
Gone but not forgotten

[Wayneo]

Forever burned into my memory. And it was due to Karloz that I 'sainted' VB for his calmness throughout the entire ordeal. 

[inteks]

thx for explanation. with the right settings it works "nerarly" as expected 
but i still think that power drops to early. could get a bit closer to configured temp!

in the srceens i use a dual nife48 coil 0.32mm 6 wraps 3mm 0.13Ohm

but the preheat is more importent with claptons....

     

[giz_60]

Try raising your 'Power' setting higher (in your profile)...looks like 42 watts in not quite bringing it up to temp...I set mine at 75 watts & let the board do its job...

[Wayneo]

I agree with @giz_60. I set mine at 75 watts & let the board do its job...       After you see what's actually required, you can, if you wish, go back and lower the watts down to steady state TC vaping. Using my pic, it's just under 30 watts, so I'd put that somewhere around 40 for my pic.

You should not lock ohms for your coil either, so the 'refinement' magic can work.