Eleaf Istick
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Gotcha.
Just wanted to Make Sure I was Interrupting what I was seeing Correctly.
So what the iStick does is Output a Fixed Voltage of ~5.5v at All Times. And numerical Values of Voltages below the 5.5v on the Screen (however the Math is Done) is Function of 5.5v On to Voltage Off with respect to some Time Period.
Where are AW batteries made?
China...... Just saying......
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Where are AW batteries made?
China...... Just saying......
Indeed. AW simply tests ALL batteries they sell to ensure they are performing to spec. How many others that rebrand batteries do that? Maybe Efest?
PWM with a 5.5 volt cap implies the stick is boosting to at least 5.5. then using PWM to drop down. Since a 3 v setting tastes to me like 4+ volts on every other mod I have, I'm assuming it is using Vave for the displayed voltage.
Come on Phil!!!! (again).
I don't have my stick with me (my work vape is a 350 mAh mini eGo with an evod), I'll try and remember to post a pic of the stick/genitank tonight. I do really like the design of the Genitank airflow control!
Come on Phil!!!! (again).
I don't have my stick with me (my work vape is a 350 mAh mini eGo with an evod), I'll try and remember to post a pic of the stick/genitank tonight. I do really like the design of the Genitank airflow control!
Most of the people in this thread that I've noticed are vaping the iStick at low wattages. I'm vaping it towards the upper end of its limit. I wonder what everyone that says theirs is working fine after a few weeks use are vaping at? Maybe I'm just pushing mine too hard...but even if I vape a constant 20 watts, I'm STILL using it within its advertised limits and the battery should last longer than mine has. I loved this little mod for a while, but for the past 3 days is has been frustrating the hell out of me.
The battery should not start to degrade until at least 300 full charge cycles. A few weeks is ridiculous. Maybe the price really is too good to be true
Just a primer on how PWM works...
With very few exceptions, PWM (pulse-width-modulation) boosts the battery voltage to a set level, usually the device's highest voltage, sometimes a bit higher. Then it pulses that voltage several times per second to obtain the overall voltage that's been set. In the case of the iStick, it apparently boosts voltage to 5.8V (according to an earlier post in the thread). Then it pulses 5.8V 48 times per second (48 Hz). Those 48 pulses per second can be very short or much longer until the output voltage looks constant on test equipment. The percentage of time (per second) that the voltage is on (vs. off) is called it's duty cycle.
The below image shows a device with a peak of 5V firing at 20%, 50% & 75% duty cycles.
Here's where it gets kind of tricky... If we multiply the peak voltage (Vpk) by the duty cycle (C%) we get the average voltage (Vavg, shown above). We know that firing a Vavg of 3.5V into our 1.8Ω coil creates much higher Wattage at the coil than a constant 3.5V.
For example, using the iStick's specs:
Ohm's Law (V²/R=W) tells us that a constant 3.5V into a 1.8Ω coil will give us 6.8W.
We also know a different formula is used to determine Watts from a PWM Vavg signal:
(Vpk²/R) * C% = W or in our case, (5.8²/1.8Ω) * (3.5/5.8) = 11.3W
6.8W vs. 11.3W is a big difference.
We use RMS (root-mean-square) Voltage to obtain the Watts that constant Voltage provides.
The iStick appears to be plugging an Average Voltage (Vavg) value into Ohm's Law, rather than an RMS or constant voltage, providing much higher Watts at the coil. If true, it's all about faulty software NOT hardware and could be fixed rather simply and cheaply with upgraded firmware in future runs.
With very few exceptions, PWM (pulse-width-modulation) boosts the battery voltage to a set level, usually the device's highest voltage, sometimes a bit higher. Then it pulses that voltage several times per second to obtain the overall voltage that's been set. In the case of the iStick, it apparently boosts voltage to 5.8V (according to an earlier post in the thread). Then it pulses 5.8V 48 times per second (48 Hz). Those 48 pulses per second can be very short or much longer until the output voltage looks constant on test equipment. The percentage of time (per second) that the voltage is on (vs. off) is called it's duty cycle.
The below image shows a device with a peak of 5V firing at 20%, 50% & 75% duty cycles.
Here's where it gets kind of tricky... If we multiply the peak voltage (Vpk) by the duty cycle (C%) we get the average voltage (Vavg, shown above). We know that firing a Vavg of 3.5V into our 1.8Ω coil creates much higher Wattage at the coil than a constant 3.5V.
For example, using the iStick's specs:
Ohm's Law (V²/R=W) tells us that a constant 3.5V into a 1.8Ω coil will give us 6.8W.
We also know a different formula is used to determine Watts from a PWM Vavg signal:
(Vpk²/R) * C% = W or in our case, (5.8²/1.8Ω) * (3.5/5.8) = 11.3W
6.8W vs. 11.3W is a big difference.
We use RMS (root-mean-square) Voltage to obtain the Watts that constant Voltage provides.
The iStick appears to be plugging an Average Voltage (Vavg) value into Ohm's Law, rather than an RMS or constant voltage, providing much higher Watts at the coil. If true, it's all about faulty software NOT hardware and could be fixed rather simply and cheaply with upgraded firmware in future runs.
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With all the many reviews of the Istick on Ytube, its interesting that not one single reviewer has said that it hits too hard or that the displayed output seemed inaccurate compared to other devices.
Problem with most reviews is that they test them for 5 minutes before pumping out a review
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I thought you said a few pages ago that although the output seems weak compared to when new, the battery life has not changed.
I dunno folks... mine is on its 10th charge cylce and I can't tell any difference in battery performance and I've been putting it on a SMOK volt tester. That's from full charge to near dead. Whatever Eleaf's definition of a "volt" is, at least it's consistent.
I have to say though, this has replaced my MVP and VV3. It's all I use now and I think people like me are the target market (never sub-ohm). I carry a little pouch with an extra coil, a second tank and some juice. Even a short USB cord but I've never needed it. It's actually quite liberating knowiing you can go a full day without worrying about power for a full and long day. The MVP is certainly nice in this regard but now it just feels like I have a brick in my pocket.
I hope other PV makers feel challenged by this little device and we see more things like it very soon.
I have to say though, this has replaced my MVP and VV3. It's all I use now and I think people like me are the target market (never sub-ohm). I carry a little pouch with an extra coil, a second tank and some juice. Even a short USB cord but I've never needed it. It's actually quite liberating knowiing you can go a full day without worrying about power for a full and long day. The MVP is certainly nice in this regard but now it just feels like I have a brick in my pocket.
I hope other PV makers feel challenged by this little device and we see more things like it very soon.
I actually understood this. What is wrong with me? 8-o
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I normally vape at 12w on a 1.5ohm coil which shows 4.2v. I think that's closer to a middle of the road setting than low wattage. I vape with the same settings on other mods with the same results.
Where are AW batteries made?
China...... Just saying......
Technically, they're just assembled in China. The cells they use are Panasonic cells made in Japan. Most reliable cells are made in Japan (Panasonic, Sanyo, Sony).
Most of the *fire batteries are recycled disassembled laptop batteries.
When Constant Voltage is being Supplied, Isn't Vpk = Vavg? And Isn't C% = 1?
How long a battery charge will last is not mysterious. It's a calculation based on Ohm's Law using current flow relative to the battery's rated capacity (in the iStick's case, 2200mAh). Certain user variables can make that calculation more complicated (length of your draw and how hard you draw), but it's not rocket science.
If you're vaping the iStick constantly near the top of its rated output (20 watts), vape time will be significantly less than for low-wattage users. One half? One third? That depends on how much current you're pulling from the battery with each draw. But, no, a 2200mAh battery vaped at 20W can't provide anything close to all-day performance.
On the other hand, you may have a defective battery. You've written that your iStick isn't hitting as hard as it did and that charging takes less time than before, so perhaps your particular battery is a lemon. All I'm suggesting is that you can calculate how much time you should get from a single charge and compare that to what you actually get.
If a Device is doing PWM, it would stand to reason that the as the Displayed Voltage approaches the Peak Voltage, that the Perceived Hit approaches that of Constant Voltage.
Not the best pic but I think the genitank looks great on this silver one!
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I don't have any numbers, nor do I understand most of what anyone is saying in this thread in regards to the numbers.
All I know is that at 3.8 volts on my istick, my vape performs similar to the 4.2 volt range if it were on my MVP or my ego twist. When I turn the voltage up above my 3.8 sweet spot, I get warmer vape with diminished flavor, and burn tastes if I take it high enough. I just tried it at 3.5 volts and it still tasted burned on the first hit. Dropping it back down to the minimum 3 volts makes it taste the way it should.
I hope some people who report diminished power are correct here. I'm not a sub-ohmer and never will be. I got the iStick as a smaller replacement to the MVP. Other than the voltage being off, I think I love this thing. It's exactly what I was looking for 3 months ago when I got my MVP. The front trigger button is a nice touch as well.
All I know is that at 3.8 volts on my istick, my vape performs similar to the 4.2 volt range if it were on my MVP or my ego twist. When I turn the voltage up above my 3.8 sweet spot, I get warmer vape with diminished flavor, and burn tastes if I take it high enough. I just tried it at 3.5 volts and it still tasted burned on the first hit. Dropping it back down to the minimum 3 volts makes it taste the way it should.
I hope some people who report diminished power are correct here. I'm not a sub-ohmer and never will be. I got the iStick as a smaller replacement to the MVP. Other than the voltage being off, I think I love this thing. It's exactly what I was looking for 3 months ago when I got my MVP. The front trigger button is a nice touch as well.
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