VW Test Question for the iTaste 134 mini

[blueGrassTubb]

Hey all!

I have an iTaste 134 mini and want to verify that the wattage ring is accurate.

For instance, I know the ring is on x watts. But how do I verify that it's outputting x watts? Do I simply use a multimeter to test the voltage and then convert to watts?

 

[p.opus]

Unless you have an o-scope it's pretty tough.

The Innokin 134 uses pulse width modulation (PWM) on the output so an inline DC volt meter will not display the proper voltage. You will need an O-scope that will be able to measure the duty cycle and the perform the calculation of the output voltage based on the duty cycle of the the PWM. Then you will need to take that voltage, measure the resistance of the coil and calculate wattage and compare it to whatever the device is set for.

Pbusardo has already done tests on it in his reviews, and he is impressed with the accuracy of the unit. Variable wattage by it's nature has some inaccuracy built in because it entirely depends on the measured coil resistance and even a small difference in +/- .1 ohm can make a big difference in whether or not it fires at the set wattage.

Variable Voltage is easier to verify. It does not rely on atomizer resistance to measure accuracy. The device either delivers the set voltage or it doesn't.

While accuracy is important, it's just a number. What is more important is can it maintain that setting. So if it is putting out 10 watts, can it continue to put out 10 watts during the entire draw or does voltage begin to sag? Does the unit put out 10 watts right before the battery dies as well as when a fresh battery is installed?

Those are the more important things to consider.

I wouldn't care if they called them "juice vapor production factor" or some lame unit of measure like that. As long as when I set the thing to put out 5 JVPF's, it puts out 5 JVPF's with a freshly charged battery installed, continues to produce 5 JVPF's during all 10 to 15 seconds of my draw, and then puts out 5 JVPF's right before the battery dies. That's what I look for in a regulated mod.

 

[blueGrassTubb]

Unless you have an o-scope it's pretty tough.

The Innokin 134 uses pulse width modulation (PWM) on the output so an inline DC volt meter will not display the proper voltage. You will need an O-scope that will be able to measure the duty cycle and the perform the calculation of the output voltage based on the duty cycle of the the PWM. Then you will need to take that voltage, measure the resistance of the coil and calculate wattage and compare it to whatever the device is set for.

Pbusardo has already done tests on it in his reviews, and he is impressed with the accuracy of the unit. Variable wattage by it's nature has some inaccuracy built in because it entirely depends on the measured coil resistance and even a small difference in +/- .1 ohm can make a big difference in whether or not it fires at the set wattage.

Variable Voltage is easier to verify. It does not rely on atomizer resistance to measure accuracy. The device either delivers the set voltage or it doesn't.

While accuracy is important, it's just a number. What is more important is can it maintain that setting. So if it is putting out 10 watts, can it continue to put out 10 watts during the entire draw or does voltage begin to sag? Does the unit put out 10 watts right before the battery dies as well as when a fresh battery is installed?

Those are the more important things to consider.

I wouldn't care if they called them "juice vapor production factor" or some lame unit of measure like that. As long as when I set the thing to put out 5 JVPF's, it puts out 5 JVPF's with a freshly charged battery installed, continues to produce 5 JVPF's during all 10 to 15 seconds of my draw, and then puts out 5 JVPF's right before the battery dies. That's what I look for in a regulated mod.

This makes an amazing amount of sense. Consistency in its functioning is more important than the number it tells me.

Unless you're a nerd who wants to believe the ring, but just can't bring himself to do it. It's more intellectual curiosity than anything. Ultimately I'm going to vape according to what I like, not some predetermined number on the dial. I'm just wondering how close it really is.

You mentioned that one couldn't tell the correct voltage with an inline volt meter, but what about a multimeter?

 

[p.opus]

You mentioned that one couldn't tell the correct voltage with an inline volt meter, but what about a multimeter?

No.

Here's what's physically happening. Lets say you have a 2 ohm resistor on the unit and you set the ring to 8 watts. Per ohms law the unit should put out 4 volts.

But it really isn't firing 4 volts DC. It uses boost circuitry to convert the output of the battery to 6 volts, then it's firing 6 volts of Pulsed DC 48 times a second. This is caused Pulse Width modulation. The duty cycle is how often it fires. The amount of the time it's on during a single duty cycle is the pulse width. The voltage out is a function of how "wide" the pulse is. A pulse that is only on for 1/3 of the duty cycle would calculate to roughly 1/3 of the peak voltage (2 volts) A pulse that is on 2/3 of the time would be 4 volts, and so on. So with a duty cycle of 1/48 (.021) of a second, the device fires 6 volts for about .014 seconds and off for about .007 seconds and repeats this as long as you hold the fire button.

Your multi meter can only read the actual peak voltage, so it will always display 6 volts out. An analog meter may show 6 volts, but the needle would quiver due to the pulsed DC signal. A digital meter may show 6 volts, or just show nothing because it's not sensing a constant "flat" DC signal out.

In any case your not reading the average result of the PWM, only the peak voltage generated.

You may hear of things like 33.3hz chipsets (common in most Sigelei's and Vamos). This just means instead of a duty cycle of 1/48 of a second, those units fire a duty cycle of 1/33 of a second).

The higher the hz, the smoother it appears.

The ProVari, for instance uses 800Hz PWM. It's duty cycle is 1/800 of a second. This is so fast that it allows ProVape to add filtering circuitry on the output so that the output voltage is a "true" flat DC signal not a pulsed signal. That's why an inline volt meter or multimeter will read correctly on a ProVari but not on other mods that don't have filtering on the output.

The MVP and VV3 don't use PWM at all. Instead, they connect two LiPO packs connected in series so that the output of the device is doubled. Then they simply step down the voltage depending on what is set by the user.