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Eleaf iStick ... compact 20w box mod
- Thread starter moecat
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Hi everyone,
I registered so that I could add my 2p.
I am a new vaper,10 a day smoker for 12 years. Now smoking 1 or 2 a week. I purchased an mvp back in August, i use it with mini pro tank 3's and love it. I also have an mini aspire nautilus, but I felt/feel that i don't quite get the best out of it on the mvp. I prefer all off my vapes pretty much through the pro tanks.
When i saw the iStick, i like many got very excited. I still am, kind of lol
It's so small. Its great. It feels great too, the screen is awesome, buttons click nicely.
I have had it for 2 days, so far, but in all honestly, i prefer vaping from the mvp, the flavour and general vape seems nicer to me. Then this evening a stumbled across this post and read through it all.
I thought i was going to get a mini mvp with more power. Which in ways it seems i have, but now i feel confused after reading about all these power issues. I'm not that tech savy with the ohms and calculations stuff yet, but i haven't needed to be with my mvp. I tend to stay around 7.5 to 8 watts with the mini pro tanks and usually 10 watts with the mini nautilus. Where as with the iStick i was getting the odd burnt taste at 7 or 8 watts on the mini protanks. So i was vaping down at 5 something.
I will give it some more time, but i don't feel like i can trust it like I can my mvp
I registered so that I could add my 2p.
I am a new vaper,10 a day smoker for 12 years. Now smoking 1 or 2 a week. I purchased an mvp back in August, i use it with mini pro tank 3's and love it. I also have an mini aspire nautilus, but I felt/feel that i don't quite get the best out of it on the mvp. I prefer all off my vapes pretty much through the pro tanks.
When i saw the iStick, i like many got very excited. I still am, kind of lol
It's so small. Its great. It feels great too, the screen is awesome, buttons click nicely.
I have had it for 2 days, so far, but in all honestly, i prefer vaping from the mvp, the flavour and general vape seems nicer to me. Then this evening a stumbled across this post and read through it all.
I thought i was going to get a mini mvp with more power. Which in ways it seems i have, but now i feel confused after reading about all these power issues. I'm not that tech savy with the ohms and calculations stuff yet, but i haven't needed to be with my mvp. I tend to stay around 7.5 to 8 watts with the mini pro tanks and usually 10 watts with the mini nautilus. Where as with the iStick i was getting the odd burnt taste at 7 or 8 watts on the mini protanks. So i was vaping down at 5 something.
I will give it some more time, but i don't feel like i can trust it like I can my mvp
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Midniteoyl
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Its great.. Just mind the higher than setting voltage, and the 510 threads ( think the chrome plating comes off and 'gunks' the threads) and you'll be fine.
Midniteoyl
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It doesnt look as bad with the Hollowed Out tank..
Tripster
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These iSticks are amazing indeed...battery longevity...form factor...build quality (minus the soft 510 connection threading)...power...um...price...screen...user friendly...minimal icons/markings/logos...battery life...never gets warm-hot while in use (charging it gets slightly warm but that is from the energy of the 18650 battery)...um...portable...discreet...functional...minimalistic design...simplicity...comfortable (pinkie on bottom...bird finger and ring finger on the back...booger finger resting on top...thumb utilizing buttons...)...usb charge port on bottom...um...vv/vw...um...spider killer (brown recluse)...fully functional paper weight...makes me popcorn!
Hermit
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What? You thought I was done with the graphs?!
Right click and 'View Image' (or similar) to see full size...
The 'requires adjustment' bit means that mean the battery gets down to 2/3, you need to make a single adjustment upwards (by some complicated to work out amount) if you want maintain the same power output. From there until empty it will stay at the same output.
OK, I think I'm done now!
Right click and 'View Image' (or similar) to see full size...
The 'requires adjustment' bit means that mean the battery gets down to 2/3, you need to make a single adjustment upwards (by some complicated to work out amount) if you want maintain the same power output. From there until empty it will stay at the same output.
OK, I think I'm done now!
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What? You thought I was done with the graphs?!
The 'requires adjustment' bit means that mean the battery gets down to 2/3, you need to make a single adjustment upwards (by some complicated to work out amount) if you want maintain the same power output. From there until empty it will stay at the same output.
OK, I think I'm done now!
Does this imply that the Vmax value (the amplitude of the PWM square wave) changes from the nominal 5.8 volts that I have measured on my oscilloscope to a lower value when the battery drops to some level of discharge?
If so, the Istick likely compensates its display for the change, but it would make it difficult to perform an accurate Mean to RMS power conversion without knowing when the shift occurred!
I made up a set of charts and graphs allowing easy conversion from the displayed voltage and coil resistance when in VW mode, to RMS watts. That chart is based on an assumed Vmax value of 5.8 volts. It sounds like life may not be that simple
The formula is: Vdisplayed * Vmax / Rcoil = Prms
I can show the intermediate formulas I used to get that simplified formula, but I am confident that formula is correct.
So, If the Istick (in VW mode) displays 8 watts, 3.8 volts and 1.9 ohms, the RMS power would be:
3.8 * 5.8 / 1.9 = 11.6 watts RMS
However if the 5.8 volt Vmax changes as the battery discharges, it becomes difficult to know when to change the Vmax 5.8 volt term in the calculation.
Best regards,
Don
Here are my tables and graphs. The red portion of the tables show the theoretical wattage, but due to the 20 watt limit of the Istick, that value can't be reached with that value of coil resistance.
The first chart is the interesting one - It shows the actual RMS watts output by the Istick for a given displayed mean voltage and coil resistance. It allows converting the displayed Istick voltage and resistance to the RMS wattage. Again, a Vmax (peak voltage of the PWM square wave) is assumed to always be 5.8 volts.
The second table just matches what the Istick already does for you. The mean watts shown on the second chart should match what is displayed on the Istick.
The last graph shows the difference between the mean watts and the RMS watts for a given displayed voltage and coil resistance.
Best regards,
Don
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Heh...and if folks eyes have not sufficiently glazed over, here's some interesting formulas relating to the Istick's display of mean (average) voltage and power, rather than the more conventional RMS:
Determine mean voltage from battery voltage and the PWM duty cycle: Vmean = Vmax * DutyCycle% / 100
Determine mean power from mean voltage and coil resistance: Pmean = sqr(Vmean) / Rcoil
Determine mean current from mean voltage and coil resistance: Imean = Vmean / Rcoil
Determine RMS voltage from mean voltage and battery voltage: Vrms = sqrrt(Vmean * Vmax)
Determine RMS wattage from mean voltage, battery voltage and coil resistance: Prms = Vmean * Vmax / Rcoil
Determine RMS current from mean voltage, battery voltage and coil resistance: Irms = sqrrt(Vmean * Vmax) / Rcoil
Determine RMS wattage from mean wattage, coil resistance and battery voltage: Prms = squrt(Pmean) * sqrrt(Rcoil) * Vmax / Rcoil
Link to my Excel spreadsheet with the tables and graphs:
http://projectmf.homelinux.com/ecig/Eleaf_Power_Calcs.xlsx
Best,
Don
Determine mean voltage from battery voltage and the PWM duty cycle: Vmean = Vmax * DutyCycle% / 100
Determine mean power from mean voltage and coil resistance: Pmean = sqr(Vmean) / Rcoil
Determine mean current from mean voltage and coil resistance: Imean = Vmean / Rcoil
Determine RMS voltage from mean voltage and battery voltage: Vrms = sqrrt(Vmean * Vmax)
Determine RMS wattage from mean voltage, battery voltage and coil resistance: Prms = Vmean * Vmax / Rcoil
Determine RMS current from mean voltage, battery voltage and coil resistance: Irms = sqrrt(Vmean * Vmax) / Rcoil
Determine RMS wattage from mean wattage, coil resistance and battery voltage: Prms = squrt(Pmean) * sqrrt(Rcoil) * Vmax / Rcoil
Link to my Excel spreadsheet with the tables and graphs:
http://projectmf.homelinux.com/ecig/Eleaf_Power_Calcs.xlsx
Best,
Don
kelli
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moecat
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"Glazed" is right, especially with how small the font is in your charts, LOL! Krispy Kreme is asking me how much I charge to restock their supply.
I agree...just tune to what you like and forget the RMS stuff. I just find it helpful to understand what is going on under the hood when weird things happen.
Plus being an engineer just makes that curiosity worse!
I started out using the Istick with Aspire Ego-style carts with BDC coils. They tasted awful and burnt using the same voltage I used with an Ego battery. I had to set the voltage to the absolute minimum to get rid of the burnt taste. Now I know why.
Since switching to the Nautilus Mini tank with the BVC coils, all issues with taste are resolved. I can run the BVC coils at almost any wattage the Istick will deliver at 1.8 ohms, although I settled on an Istick 8 watt setting (12 watts RMS).
Also, the Nautilus Mini has a spring-loaded center pin, which compensates for the lack of one on the Istick.
With the Nautilus Mini, I can definitely perceive the "rattlesnake" pulsing of the Istick. It doesn't bother me at all, but that 56Hz is definitely perceptible.
Curiosity satisfied...back to vaping!
Best,
Don
Plus being an engineer just makes that curiosity worse!
I started out using the Istick with Aspire Ego-style carts with BDC coils. They tasted awful and burnt using the same voltage I used with an Ego battery. I had to set the voltage to the absolute minimum to get rid of the burnt taste. Now I know why.
Since switching to the Nautilus Mini tank with the BVC coils, all issues with taste are resolved. I can run the BVC coils at almost any wattage the Istick will deliver at 1.8 ohms, although I settled on an Istick 8 watt setting (12 watts RMS
).Also, the Nautilus Mini has a spring-loaded center pin, which compensates for the lack of one on the Istick.
With the Nautilus Mini, I can definitely perceive the "rattlesnake" pulsing of the Istick. It doesn't bother me at all, but that 56Hz is definitely perceptible.
Curiosity satisfied...back to vaping!
Best,
Don
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Hermit
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Hey Don,
Yes, once the battery is below a certain level it uses a lower amplitude PWM (about 4.8V) for any settting that allows it - which does make it a whole lot more complicated! I've been saying 2/3 charge, but that is approximate - it appears to be at, or soon after, the meter drops to showing 2/3 (6/9 pixels if you take a magnifier to it).
The only sensible way to handle it is to consider the two modes separately:
1. above 2/3 charge or set to output more than 4.8V (mean).
2. below 2/3 charge and set to output 4.8V (mean) or less.
These graphs show it: http://vapingunderground.com/threads/eleaf-istick-compact-20w-box-mod.17063/page-11#post-153652
Scope traces here: http://vapingunderground.com/threads/eleaf-istick-compact-20w-box-mod.17063/page-10#post-149462
I have a spreadsheet that is an absolute mess of formulae, just to produce the graphs - I have no goal to produce neat formulae to present, and I'm not sure it's even possible! I have those for it applying current and voltage limits to its mean calculations (lots of 'if's), then for Vavg to Vrms at whichever Vpeak, then extra versions for the wattage displayed/actual comparisons. It has, erm, evolved! I have the conversion from Wavg to Wrms as:
Wrms = sqrt(Wavg * R) * Vpeak / R
sqrt(8 * 1.9) * 5.8 / 1.9 = 11.9
Which is the same as yours. (Rounding errors on the display explain the difference to your example Wrms result). There's an extra condition to decide which Vpeak to use, for the '2/3 charge or below' case, based on sqrt(Wavg * R) > 4.8 (i.e. Vavg > 4.8V). Of course, that conditional makes the thing discontinuous, hence what I call the 'gap'.
Hermit
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Midniteoyl
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I was directed here for my questions on the istick. I hope this is the right place as I am new to this forum. I just bought two isticks and the first one I used worked fine the first evening I used it the next morning it would not work on any atty I tried. I gave me the message no atomizer. I tried several that I know are good. I was using nautilus both regular and mini versions. The second istick is working fine and I love it. There are some figures and numbers that come up while it is being used that I don't know what they are. The information that comes with the istick is minimal and does not help. Can you give me some information on the problem and a solution. Thanks gwaiyine
Heh...must be my inner nerd coming out, but that all made perfect sense to me!
That drop in Vmax I have not seen mentioned anywhere else but here. I found your previous charts and that "band gap" is explained very well, given the behavior you describe. It's just hard to represent in an "easy" way. I agree, no single formula can show it. Guess I could do another chart that shows the wattage correction at full charge, another where the voltage boost drops the Vmax when the voltage is set below the limit you mentioned. Nice catch!
I guess an important point to make here is that the Istick is not showing the "wrong" numbers on its display. The displayed numbers and operation are correct for Vmean. It's just that RMS is a better way to calibrate a device that is driving a resistive load with an AC waveform, like an incandescent light bulb or resistive heating coil. It better approximates what a DC voltage would do in terms of heat or light output.
In VW mode, the Istick will regulate the volts to maintain the set watts just fine, just like a device calibrated in RMS, which has become the vaping standard. Once you find the sweet spot for your setup, leave it and the Istick will maintain a nice constant power level. You would only potentially notice a difference if you changed coil resistance in your setup and expected the Istick to maintain the same vaping feel without some minor tweaking in the watts setting.
The correction chart is only really useful when you want to compare what the Istick displays to a wattage recommendation for a certain coil/tank combination where the author is referencing an RMS setting....which is what I wanted to do when I created the charts.
And I love the Bat-chart - especially having worked for Motorola for 30 years!
Don't panic....be happy!
Best,
Don
That drop in Vmax I have not seen mentioned anywhere else but here. I found your previous charts and that "band gap" is explained very well, given the behavior you describe. It's just hard to represent in an "easy" way. I agree, no single formula can show it. Guess I could do another chart that shows the wattage correction at full charge, another where the voltage boost drops the Vmax when the voltage is set below the limit you mentioned. Nice catch!
I guess an important point to make here is that the Istick is not showing the "wrong" numbers on its display. The displayed numbers and operation are correct for Vmean. It's just that RMS is a better way to calibrate a device that is driving a resistive load with an AC waveform, like an incandescent light bulb or resistive heating coil. It better approximates what a DC voltage would do in terms of heat or light output.
In VW mode, the Istick will regulate the volts to maintain the set watts just fine, just like a device calibrated in RMS, which has become the vaping standard. Once you find the sweet spot for your setup, leave it and the Istick will maintain a nice constant power level. You would only potentially notice a difference if you changed coil resistance in your setup and expected the Istick to maintain the same vaping feel without some minor tweaking in the watts setting.
The correction chart is only really useful when you want to compare what the Istick displays to a wattage recommendation for a certain coil/tank combination where the author is referencing an RMS setting....which is what I wanted to do when I created the charts.
And I love the Bat-chart - especially having worked for Motorola for 30 years!
Don't panic....be happy!
Best,
Don
Hey Don,
Yes, once the battery is below a certain level it uses a lower amplitude PWM (about 4.8V) for any settting that allows it - which does make it a whole lot more complicated! I've been saying 2/3 charge, but that is approximate - it appears to be at, or soon after, the meter drops to showing 2/3 (6/9 pixels if you take a magnifier to it).
The only sensible way to handle it is to consider the two modes separately:
1. above 2/3 charge or set to output more than 4.8V (mean).
2. below 2/3 charge and set to output 4.8V (mean) or less.
These graphs show it: http://vapingunderground.com/threads/eleaf-istick-compact-20w-box-mod.17063/page-11#post-153652
Scope traces here: http://vapingunderground.com/threads/eleaf-istick-compact-20w-box-mod.17063/page-10#post-149462
I have a spreadsheet that is an absolute mess of formulae, just to produce the graphs - I have no goal to produce neat formulae to present, and I'm not sure it's even possible! I have those for it applying current and voltage limits to its mean calculations (lots of 'if's), then for Vavg to Vrms at whichever Vpeak, then extra versions for the wattage displayed/actual comparisons. It has, erm, evolved! I have the conversion from Wavg to Wrms as:
Wrms = sqrt(Wavg * R) * Vpeak / R
sqrt(8 * 1.9) * 5.8 / 1.9 = 11.9
Which is the same as yours. (Rounding errors on the display explain the difference to your example Wrms result). There's an extra condition to decide which Vpeak to use, for the '2/3 charge or below' case, based on sqrt(Wavg * R) > 4.8 (i.e. Vavg > 4.8V). Of course, that conditional makes the thing discontinuous, hence what I call the 'gap'.
The unit that is showing "No atomizer" very likely has a defective connection to the connector internally, as it is showing the message with a variety of different atomizers. From personal experience, I know the Nautilus Mini has a spring-loaded center contact that is probably making good contact with the center pin on the Istick. Sorry to say, there is likely a manufacturing defect with that unit. You could try prying the center contact up slightly with a pick, but that might damage it as the conctact appears to be held in place with silicone sealant, from the internal photos I have seen.
Don
don, your engineering prowess does not go unappreciated. i can appreciate it and still not understand it tho!
Glad my prowess is recognized in at least some areas! Thanks for the appreciation!
Best,
Don
Hermit
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For the voltage display and VV mode, sure, 'wrong' is debatable. I would lean towards saying it's wrong though, just because it's a VV/VW device rather than just a VV device, so it should know better!
The displayed power numbers are wrong, whichever way you look at it. Any distinction of Mean vs RMS Power is just a way for us to label Powers that are derived from (or produce) Mean vs RMS Voltages, in the context of this discussion. In reality, when using:
W = V² / R
we actually need to use RMS volts to get the Mean Power of the AC signal; using Mean volts doesn't produce a meaningful Power value.
VW mode isn't really much different to its VV mode - in VW mode it simply reads the coil resistance before firing, and then calculates the voltage to use. From there on it's the same as VV mode set to that voltage.
In either mode it will keep a steady output, from full to empty charge, only if you stay within the green band of my last graph
I've grown used to the quirk of it dropping in output when it gets down to 2/3 charge, and just click the 'up' button a few times to compensate. It's not a big deal really, as long as the blue region on that graph is where you want it. I tend to use VV mode since it makes any mental calculations easier!For the voltage display and VV mode, sure, 'wrong' is debatable. I would lean towards saying it's wrong though, just because it's a VV/VW device rather than just a VV device, so it should know better!
The displayed power numbers are wrong, whichever way you look at it. Any distinction of Mean vs RMS Power is just a way for us to label Powers that are derived from (or produce) Mean vs RMS Voltages, in the context of this discussion. In reality, when using:
W = V² / R
we actually need to use RMS volts to get the Mean Power of the AC signal; using Mean volts doesn't produce a meaningful Power value.
VW mode isn't really much different to its VV mode - in VW mode it simply reads the coil resistance before firing, and then calculates the voltage to use. From there on it's the same as VV mode set to that voltage.
In either mode it will keep a steady output, from full to empty charge, only if you stay within the green band of my last graph
Yes, I think I need to retract my statement that it is not wrong.
I ran the following graph for just the 2.0 coil setting, with an extra trace showing the change due to the Vmax shift when the battery indicator shows < = 2/3. It shows that the Istick will display a nice-looking continuous wattage and voltage even when the Vmax steps down at 2/3 battery. However, since the actual user experience is governed by the RMS power rather than the mean power, the user will perceive a sudden drop in power when the battery hits 2/3 and lower.
In my case, I use a BVC coil that reads 1.9 ohms, which is pretty close to this graph. I run it at an Istick displayed wattage of 8.0, which is actually about 12 watts RMS. However, when the battery drops to 2/3 or less, the RMS watts drops to 9.6, although the Istick won't show any change on the display at all - watts or volts.
A 2.5 RMS watt drop would likely be quite noticeable. That is just plain wrong on the part of the designers. Is it a deal breaker for the Istick? Not for me, as long as I'm aware of it. However the user will likely feel the difference even though the display will show absolutely no sign of the sudden shift at 2/3 battery..
It also makes the VW mode less useful, as it is supposed to maintain the watts over any variation in coil resistance by adjusting voltage to maintain the watts. It won't.
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Yes! I agree, I'm keeping it low, power wise, and pushing 2 ohms on a clearomiser and getting between 3 and 4 days out of a charge.IIIIIIIIIIIIIIIIIII Like it!
Oh cripes, neither can I. I'm screwed this Black Friday. I can feel it in my bones.I don't need to be temped - and I already have one, which anyway is just a backup to my backups
Has anyone seen a good sale usa on the Eleaf Lemo? I keep checking but most sites are out of stock when I find one
What's a good price for those? I'm looking around now
There coming in around $42...I would like to find it under of course but I don't want to wait for china vendor...need it by Christmas as a gift. Found maybe 2 sites that say they have it but when i add to cart it then turns out of stock
Yeah, I was going to suggest FT. Last I looked they had them but that;s not an option for you. I might be looking for an istick if you know anythingThere coming in around $42...I would like to find it under of course but I don't want to wait for china vendor...need it by Christmas as a gift. Found maybe 2 sites that say they have it but when i add to cart it then turns out of stock
I think http://www.vapordna.com had istick all colors $34.99
http://www.vapercompany.com/Eleaf-Lemo-RBA-p/e16lemo.htm $33.95 Sorry, out of stock
Thanks muth....I tried them and emailed with no response....there out of stock was a really nice price too
Question...did you buy a Aspire Atlantis? I am wondering about the spare coils...I don't see those being sold yet
I am trying to get a jump on this shopping and omg everything new coming out already out of stock..
was a really nice price tooQuestion...did you buy a Aspire Atlantis? I am wondering about the spare coils...I don't see those being sold yet
I am trying to get a jump on this shopping and omg everything new coming out already out of stock..
Press drop down......out of stock
it's crazy
Oh, I'm sorry. I didn't think to try the drop down. No Atlantis for me. I don't really see the point in it. Not for me, anyway. I usually don't buy the next new thing until it's oldPress drop down......out of stock
I like to see how it works out: complaints, improvements, tweeks, price drop,etc. Kinda like a car - never buy the first year model.Also, people tend to lose their minds around these Black Friday sales. Only a select few are really deals. If you can wait till after the holidays, you really get the deals. lol gotta say good night. Thanks for everything.
Thanks Artemis, I grabbed one
http://rockbottomvapes.refr.cc/J76T7CJ Just got this for buying something. 10% off till Dec. 30
Just completed the O Ring trick on my iStick and it works great. #60 O Rings from Lowes. It looked like I was going to destroy the thing trying to get that center pin raised and then to get the ring in place. Had to do it twice.
First time I was real pleased that the O Ring was in place and just pushed down on the center pin. Wrong! It basically slipped through the O Ring so had to start all over. Once you get that O Ring over the pin, use a small screw driver or point to first push the O Ring down inside the channel, then push the pin down. New life for the iStick