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SMA SDNA75 Mod resistance measured


mactavish
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These SMA SDNA75 devices were setup software wise by DJLSB, a very knowledgeable reviewer. They come with wire presets, that I have since changed. However he did include device resistance settings. I can't confirm the case thermal numbers as I have not run those tests. The only one I can test is the the main device resistance in "Atomizer Analizer", using the solid cooper 510 plug that was sold through a member on this forum, look in the DNA200 thread. You first set the resistance to ZERO, upload the settings back to the device, then run the test. The original value that has been preset on the device was: 0.0016 My test showed 0.002 on 3 of them, and 0.003 on the 4th. This under Escribe version 1.2 There are other ways to short the 510, if you don't have this custom copper plug. Feel free to add your results to this thread.

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I also changed the wire settings and mod resistance on my SDNA75. I made the 510 shorting tool from a used cartomizer with it's 510 filled with solder. The value I got was close to the original setting, I got 0.002?.
BTW, I have 5 other DNA200 mods, they are all 0.004? or slightly higher.

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Swainesmatee said:

I got .006 on my vt75 nano using the copper calibration tool

Agrees exactly with my results. I wonder how Daniel did his tests. I would write him, but he never returned my last two messages in the past on other issues, so I don't bother anymore.
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Jentz9517 said:

so 0.006 for the nano guys?  also post up your case analyzer values if you have them it's gonna be a bit before I can test mine but will put it up when i do.. 
specify battery also

I left those as they came. DJSLB set those up, hopefully they are accurate. Those tests are the hardest to requiring some special heat sinks. If you have them, would love to see your results.
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dwcraig1 said:

Much better and consistent with what others are reporting. 

Yeah, gives me a bit more confidence in DJLSB's 0.0016 preset. Now that I'm managing 4 different SMY SDNA75's, I'm going to use 0.002 on all of them, even though one read at 0.003. This way if I want to change any other mod settings, I'm only dealing with a single Escibe file, not four. I'll have to trust his case settings as doing those tests requires some good heat sinks, ones I never bothered buying.
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Lilpetabread said:

How tight do you guys screw your 510 plug down? Until it literally can't screw down any more? I'm always afraid to crank down too tightly.

I tightened until it bottomed out and just nice and snug until completely stable with no fluctuation the triade remained stable at 0.004 for the last two turns I guess a fair bit tighter than an atomizer
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Jentz9517 said:

I tightened until it bottomed out and just nice and snug until completely stable with no fluctuation the triade remained stable at 0.004 for the last two turns I guess a fair bit tighter than an atomizer

Okay thanks, that's what I've been doing too. On my VT75, when I screw the plug all the way down tight, it makes a huge gap between the c-frame and the rest of the device's body near the 510. I love the looks of the VT75 (red) but the gaps around it drive my OCD nuts! (on both of my VT75s). Thanks for sharing your results!
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I'm surprised this wasn't mentioned before so here goes. I just checked my SDNA 75 again for mod resistance, not only was I wanting to see than it was still 0.002? but wanted to see how many digits the the right of the decimal point it reads and it's 3. So how did  DJSLB come up with ).0016?? Just something I was thinking about, perhaps he measured it with other means.

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dwcraig1 said:

I'm surprised this wasn't mentioned before so here goes. I just checked my SDNA 75 again for mod resistance, not only was I wanting to see than it was still 0.002? but wanted to see how many digits the the right of the decimal point it reads and it's 3. So how did  DJSLB come up with ).0016?? Just something I was thinking about, perhaps he measured it with other means.

correct if i'm wrong but aren't you supposed to take 80% of what you see in AA and apply that number to the mod res field?

80% of 0.002 = 0.0016

i left mine at .0016 i don't have the tool or the ambition to make one with solder. you think a bolt with the correct threading would work?
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dwcraig1 said:

I'm surprised this wasn't mentioned before so here goes. I just checked my SDNA 75 again for mod resistance, not only was I wanting to see than it was still 0.002? but wanted to see how many digits the the right of the decimal point it reads and it's 3. So how did  DJSLB come up with ).0016?? Just something I was thinking about, perhaps he measured it with other means.

In his latest video, he has moved, and made a new office. It's a long winded video, no devices reviewed, but he does reverse the camera and show some of the tools he uses. I don't recall anything specific like a scope, but I was not paying 100% attention. Take a look at it if you have time, perhaps you can pick up on it. He does briefly point out his heat sync devices. I noticed these on his desk as at one point as I was considering buying them. They are used to get all the case thermal numbers. Not that costly, and there is a thread on here where one of the mods discusses them, just too limited for me as a single use tool.
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ChunkyButt200 said:

correct if i'm wrong but aren't you supposed to take 80% or what you see in AA and apply that number to the mod res field?

80% of 20 = 16 

Not if you use the 99% copper plug. You use the actual ohms you see on the screen. Look earlier in this thread as I put the link to the original discussion.
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mactavish said:

Not if you use the 99% copper plug. You use the actual ohms you see on the screen. Look earlier in this thread as I put the link to the original discussion.

this is part of a quote from a post from James on mod resistance calibration......

"(2) Always make sure the Mod Resistance you have is conservative -- keep the value you enter at or lower than the real Mod Resistance. If the value you enter is higher than the real ModResistance of the device, it can negatively affect the stability of the temperature protection system. It's best to measure it if you can, honestly. And then use, say, 80% of that value to give yourself some margin.

Having a fairly accurate Mod Resistance will deliver a more accurate power and temperature.
The compensation is really only notable in extremely low Ohm coils where the 510's resistance is significant though."

here's the link to what i quoted....

https://forum.evolvapor.com/topic/65594-topic/
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ChunkyButt200 said:

this is part of a quote from a post from James on mod resistance calibration......

"(2) Always make sure the Mod Resistance you have is conservative -- keep the value you enter at or lower than the real Mod Resistance. If the value you enter is higher than the real ModResistance of the device, it can negatively affect the stability of the temperature protection system. It's best to measure it if you can, honestly. And then use, say, 80% of that value to give yourself some margin.

Having a fairly accurate Mod Resistance will deliver a more accurate power and temperature.
The compensation is really only notable in extremely low Ohm coils where the 510's resistance is significant though."

here's the link to what i quoted....

https://forum.evolvapor.com/topic/65594-topic/

From what I have read, this is only true if you're using an RDA with copper wire, due to the the fact that the RDA itself has a resistance. By subtracting 20% of the final Mod Resistance value, you're subtracting the RDA's potential added resistance. On the other hand, using the copper plug - you use the full Mod Resistance value due to the fact that there is no other resistance taken into account, as the plug isn't threaded into something like an RDA that would raise the final Mod Resistance value. I hope that makes sense!
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