bmclaurin

Thanks for the tip and heads up. But can you purchase the screen separately from the board (when supplies are available)? I didn't see any listings for that anywhere but probably am missing something obvious.

Board still fully functional, just permanently in stealth mode. Lol. Anyone know where I can find a replacement?

Sorry to hear that, DDolan. My experience has been much more positive than yours. What TC wire material are you using? I've found working with nickel to be a bit tedious, but titanium OTOH has worked quite well for me. Also, have you tried a few different atty's? Or perhaps the atomizer analyzer? Regardless, I hear you on being frustrated. TC in general is great on the one hand, but sometimes I just prefer the simplicity of my VW or mechanical devices.

How do you guys see anything on the screen while you're vaping? What am I missing? As to your question, wouldn't it be showing voltage and/or current being applied to the atty? (i.e., not what is being drawn from the battery)

I have had zero luck with SSV's .csv file for the 0.4mm wire. I use either their 0.5mm .csv file (even if I'm building with 0.4mm wire) or the Titanium1 .csv file from Steam Engine. The SSV .csv curve for the 0.4mm wire is way too steep. I would love to hear an explanation on why the same material supposedly requires two different curves. Makes no sense to me.

Sorry if you've already said this, but have all the builds you've tried thus far been on the same atty? Have you run the atomizer analyzer? Your builds seem to be very low resistance, so it's especially important that your atty/build is very stable.

Check a couple obvious things first. 1) Under your profile settings in eScribe, is the Temperature button set to 'On?' 2) On the 'Mod' tab, under 'Manufacturer Settings,' what is your ohm lock range %? 3) Double check that you have the appropriate coil material (and associated TCR/TFR loaded) for each profile. 4) Do you have a mod resistance set? If so, what is it? Also, .009??? Is that a typo?

I don't know why I'm bothering replying, but the DNA 200 considers a battery "empty" when it can no longer sustain a 5W discharge, and it will lower the power to draw every bit of capacity down to that limit. Doesn't matter how low you set the LVC if you're hitting that limit. And, btw, the voltages in eScribe's .csv files are resting voltage, not under load.

Not sure how to interpret your response. I was attempting to respond to your question. Sorry I wasted my time.

Nothing wrong, per se, with lowering the LVC. IIRC, the DNA 200 supports LVC's down to 2.8v. The default value of 3.09v is a compromise between runtime and cycle life. Lower values will give slightly more runtime at the cost of cycle life. Whether that trade-off is worth it is up to you. I will point out, however, that once you reach the ~3.0-3.1v range (and, yes, I'm talking about voltage under load), lithium-based cells have already depleted most of their capacity, especially at the relatively high discharge rates that are typical in vaping. You can see this in Samsung's own discharge profile curves that you posted. Looking at the dark green (10A discharge) curve, at 3.1v the cell has given about 2.3Ah. If you follow that curve to the 2.8v point (which I believe is the lowest the DNA 200 supports), the cell has given about 2.5Ah. So by lowering your LVC from 3.1v to 2.8v you've gained about 200mAh of capacity (roughly a 9% increase). That's not an insignificant increase in capacity. For my vaping style, that would probably net me an additional ~50 puffs or so on a 3S configuration. But it would stress the cells a good bit to do this, which would have at least two drawbacks: (i) reduced cycle life and (ii) quicker reduction in capacity over the life of the cell. So, in the long run, I'm not sure it's all that advantageous to go much lower than the default 3.09v LVC. Again, whether the trade-off is worth it is entirely up to you.

Nice tip, Margucci. I'll have to give that a try.

Yep, works fine. I did a fused Clapton with a strand of 32 gauge Nichrome 80 wrapped around two straight, parallel strands of SSV Ti wire 0.5mm. Then did 5.5 wraps around a 3mm post. Settled in at 0.11 ohms cold. Note that this is a single coil. It would be too low in dual coil setup.

It's a VHO Haze Dripper Tank RDA. https://bevapehappy.com/shop/haze-dripper-tank-by-vho/ Very strange looking indeed, but it has great flavor. The plastic thing is a chamber reducer that helps concentrate the vapor (and flavor). It has a large juice well (small tank, I guess) underneath. There is a cylinder sleeve (not in pic) that fits down around the bottom portion to hold the juice. The wick feeds down through two holes in the deck to reach the juice well. It has an offset drip tip that also adds a unique twist on the flavor. Anyway, on the build, it was wrapped as a contact coil, but I loosened it up a bit by wiggling it with my screwdriver to work out the hot spots. And, yes the rightmost loop got angled out a bit when I tilted it. Yeah, a 24-gauge parallel titanium core is gonna go way low in a dual coil. The parallel 0.5mm Ti wire core in my pictured build above is basically 24-gauge. And settled in at 0.11 ohms with 5.5 wraps around a 3mm post, obviously in a single coil. Too low for a dual coil, which is why I mounted it on that particular RDA, since it was basically designed for single coil.

I wrapped it as a contact coil, but once mounted, I used my screwdriver to wiggle it around a little work out the hot spots. Obviously, you have to be careful doing this with a titanium core. Just use a low wattage setting in power mode for this. The ramp-up time is not bad at all with the 32-gauge wrap (especially using preheat), but I'm going to build another one with a 36-gauge Nichrome 80 wrap (instead of 32) to cut it down even more. I think the 36-gauge wrap will cause it to heat almost instantaneously. Unfortunately, I have to wait for the 36-gauge to arrive in the mail. EDIT: It helps to have a 4-post atty, because the coil is pretty wide at 5.5 wraps. Even with a 4-post atty, I had to tilt it a little bit to clear the top cap. Obviously, I'm no coil artist, but it gets the job done.

I just built a fused Clapton with a single strand of 32 gauge Nichrome 80 wrapped around 2 straight parallel strands of 0.5mm SSV Ti wire. Then did 5.5 wraps around a 3mm post, and it measures 0.11 ohms cold. Mounted it as a single coil in a Haze Dripper Tank RDA with reduced chamber plug. I used SSV's 0.5mm TFR curve, and it seems to work perfectly. The flavor of this build is off the charts good.

Guys, I have no experience with SS coils, so take what I say with a grain of salt. But at TCR's that low, isn't your temperature accuracy going to be severely degraded? I think that limit is there, by design, for a practical purpose, not a technological one...

You need a TFR curve that is specific to the material of your coil in the form of a .csv file that you upload to your DNA 200 via eScribe. You can generate a .csv file on steam-enging.org's Wire Wizard tool: http://www.steam-engine.org/wirewiz.asp Using the wire wizard, just select your material from the dropbown list and then click on the 'DNA 200' tab to download the TFR curve as a .csv file. Then go to the profile of your choosing in eScribe's 'General' tab and select 'Custom' coil material from the dropdown list. Then load your newly saved .csv file into that profile using the 'Load CSV...' button. Then click on the 'Upload Settings to Device' button.

It would be handy if we could have the ability to upload multiple "battery profiles" to the device (each with their own specified Wh capacity and .csv file) and select them on the fly from the device. As it currently stands, if you want to have the ability to swap out batteries of differing capacities and maintain the integrity of the battery meter, it seems it would be necessary to manually change the capacity in eScribe each time you change batteries and upload the new settings to the device.

I completely agree that, in principal, the chip could measure how many watt-hours had been drawn from the battery and simply subtract that from the total estimated capacity (as input in eScribe) to determine and display remaining capacity. But, to do this, the chip has to know where it's starting from. Let's say I remove my battery from my device and give it a partial charge on an external charger (which could be a common occurrence with 18650's, for example). When I place the battery back into the device, how does the chip know where to start subtracting from? My original post for this thread was making an educated guess that this is where the .csv file comes into play. I'm guessing that the chip must use the .csv file to make a preliminary estimate of state of charge (by measuring the battery's OCV) and, from that point forward, it uses actual watt-hours drawn to estimate remaining capacity. So, I guess I'm saying (speculating/guessing) that the chip uses a combination of these two methods (i.e., open-circuit voltage and watt-hours drawn). I guess I'm also saying that the second method alone (i.e., watt-hours drawn) is insufficient because it couldn't account for the effects of external charging, etc. Sorry to be so tedious with this. None of this is necessary to be able to safely and satisfactorily use the DNA 200.

I'm saying that in your first scenario (where remaining capacity % is determined by voltage), the discharge profile curve (.csv file) compensates for the large changes in displayed capacity that would otherwise occur at full charge and near empty. Let's say your .csv file was just a straight diagonal line consisting of two points: (0%,3.1v) and (100%,4.2v). In that case, yes, you would not get a smooth change in displayed capacity % at full charge and near empty. But the .csv file contains multiple points (resulting in a curve) that account for the non-linear drop in open-circuit voltage as the battery's charge depletes. Thanks for sticking with me through this. I like understanding how things work.

Thanks, Margucci, but that's what the discharge profile curve does. It compensates for the non-linear decline of the battery's OCV (open circuit voltage) as its charge is depleted. What you're describing would be true if the .csv file contained just a straight diagonal line as opposed to a curve. EDIT: My apologies if I'm coming across as argumentative, as that is not my intent. I'm truly just trying to understand how this works (for curiosity's sake).

Thanks for the responses, guys. I understand how the battery analyzer works, and I've used it to determine my pack's actual capacity. And I understand that a battery's total capacity is correlated with rate of discharge. The reason I made the original post of this thread was simply to try to understand how the chip uses this information to estimate remaining capacity (i.e., state of charge) of that battery at any given point in time. In particular, I don't understand how the on-board battery meter uses the battery's estimated total capacity (as input in eScribe), especially since the on-board meter only displays state of charge as a percentage of total capacity (as opposed to the number of watt-hours remaining). The on-board battery meter could determine state of charge (as a percentage of total capacity) simply from a measure of the battery's resting voltage and a lookup in the discharge profile .csv file. If you handed me your battery and your discharge profile .csv file, and you never told me the total capacity of the battery, I could still give you a decent estimate of what portion (as a percentage) of its total capacity is remaining simply by measuring its open circuit voltage with a DMM and looking up that voltage in your .csv file. I don't need to know the pack's total capacity (in watt-hours) to make that estimate. And I don't need to know how much you had been vaping it prior to handing it to me. So, I guess my question really boils down to: Why does the on-board battery meter seem to be influenced by the value that I input into eScribe for the pack's total capacity? How does it use that information?

I've thought about a similar design myself but so far haven't attempted to model anything out. I'll be tracking your progress with interest. How are you planning to deal with the grip/cover? I suppose you could make one if you could find a sheet of rubberized plastic that could be cut/bent to size/shape. Not sure on the size of the long bolts, but I have quite a few different sizes lying around, so I'll try to find one that matches and let you know.

...and the 3.66v LVC that they recommend is silly. But, guys, on the mod resistance... If you have, say, a mech mod with a copper pin, you can use that to get a pretty good reading on your mod resistance. No doubt, a threaded copper plug would be better, but it will still get you pretty close. Just pull the pin out of your mech mod and insert it into the 510 connector. press it down with something non-conductive so it makes good contact with the positive and negative surfaces of your 510 connector. Move it around a little until you get a steady reading. That's all there is to it. Mine came in at 0.007 ohms as you can see in the pics below.

One thing about the SSV Ti wire that makes no sense to me is the fact that SSV has published two different TFR curves--one for the 0.4mm version and another for the 0.5mm version. Unless the two different versions have a different chemical composition (i.e., different alloys), I am at a loss as to why they would have different temperature profiles. The curve they published for the 0.5 mm version is much closer to "traditional" Grade 1 titanium wire, and I have much better (or at least, more consistent) results using that curve (the 0.5mm curve), regardless of which thickness (0.4mm or 0.5mm) that I'm actually using in my build. The published curve for the 0.4mm wire is much "steeper" than the published curve for the 0.5mm wire. If those wires are in fact the same alloy (which, unless someone corrects me, I believe they are), then the DNA 200 is going to impute a lower temperature for a given resistance using the 0.4mm curve versus what it would impute using the 0.5mm curve. On single wire builds (e.g., standard dual coils), the effects of this discrepancy aren't hugely noticeable (to me, at least). But on builds with higher mass, it becomes much more noticeable. I did a 2-strand twisted (1.2 mm pitch) dual coil build earlier today, 5.5 wraps around 3mm post, which settled in at 0.10 ohm cold. Using the 0.4mm TFR curve, with a temp setting of 420F, the vape was much too hot. Certainly hotter than 420F. It was plainly evident while vaping it that it was overheating. Meanwhile, the device monitor showed that it wasn't even hitting the 420F temp limit, which was BS. So I switched over to the 0.5mm curve (even though I was using 0.4mm wire), and all was well. If you fiddle around with the Wire Wizard over on SteamEngine, you can see that the TFR curves don't change simply by changing the diameter of the wire, as long as the wire material is the same. So I don't see why the SSV Ti wire would have two different curves for the two different wire diameters (again, unless they are different alloys, which I doubt). Makes no sense to me. So, unless someone can point out for me what I'm missing, I'm steering clear of the 0.4mm curve for now.