Eleaf Istick - Easy Mean to RMS Conversion Formulas

[workman70]

So, by that math...and not questioning it, just wanting to understand it, on the istick showing 8 watts, the conversion is 11 watts RMS. That's a 3W delta...does that seem to match up to those that have scoped it?

 

[Auxx]

So, by that math...and not questioning it, just wanting to understand it, on the istick showing 8 watts, the conversion is 11 watts RMS. That's a 3W delta...does that seem to match up to those that have scoped it?

I checked the values from my calculator with Busardo's review - they match perfectly. So the math is correct.

 

[raitizz]

Ok, and how do we convert this to the new Istick 30W with max 8 V?

To rephrase, on the new iStick 30W - putting on a nautilus Mini with a 1.8 Ohm coil (lets say it IS actually 1.8), put it on 11W - is it firing at 11W or not? Still can't get my head around this.

A friend of mine just ordered this new iStick and I know, I'm gonna be the one, who has to explain that RMS thing to him...

Thanks,
R

 

[VapingTurtle]

donf99 and Auxx, I just wanted to tell you what a breath of fresh air it is to see posters here who understand switched voltage regulation. That's pretty rare around here. I see so much misinformation on here and it drives me crazy! Thank you!


EDIT: Watts_rms does not apply to our switched DC voltage regulators. We do calculate Watts (not W_rms) from V_rms.

 

[VapingTurtle]

Ok, and how do we convert this to the new Istick 30W with max 8 V?
...

Without calculating it yourself, just use Auxx's Mean to RMS Calculator and change Vmax to 8v (if that is indeed the correct Vmax for the Istick 30).

(Or donf99 stated all of the pertinent formulas above.)



EDIT: Naaaa... I was wrong here... see below.

 

[raitizz]

Without calculating it yourself, just use Auxx's Mean to RMS Calculator and change Vmax to 8v (if that is indeed the correct Vmax for the Istick 30).

(Or donf99 stated all of the pertinent formulas above.)

Thanks.
I tried that.
Vmax of the iStick 30W = 8 V
Resistance of coil = 1.7 Ohms
Desired Watts in Wrms = 12 W
The rest is calculated. Something's not right..



R

 

[VapingTurtle]

Ok, and how do we convert this to the new Istick 30W with max 8 V?

To rephrase, on the new iStick 30W - putting on a Nautilus Mini with a 1.8 Ohm coil (lets say it IS actually 1.8), put it on 11W - is it firing at 11W or not? ...

Yes, it is firing at 11watts. The new iStick30 appears to display V_rms and calculate Watts with V_rms. BIG improvement over the iStick20!! (I do not have a scope. I am basing this on an in-line voltmeter.)

I am not an engineer. I may be wrong. (Then again, an engineer may be wrong too.) But I've studied this a little bit. Just a bit. I was wrong to heap praise on donf99's OP without thinking about it a bit.

donf99 was wrong to refer to W_rms. It does not apply to DC or pulsed DC current. W_rms is only used in applications involving AC, usually with regard to audio amplifier max output. We are only interested in Watts as calculated by Joule's first law.


I would really like engineers with applicable experience (and proper equipment) to comment on this.

 

[raitizz]

Yes, it is firing at 11watts. The new iStick30 appears to display V_rms and calculate Watts with V_rms. BIG improvement over the iStick20!! (I do not have a scope. I am basing this on an in-line voltmeter.)

I am not an engineer. I may be wrong. (Then again, an engineer may be wrong too.) But I've studied this a little bit. Just a bit. I was wrong to heap praise on donf99's OP without thinking about it a bit.

donf99 was wrong to refer to W_rms. It does not apply to DC or pulsed DC current. W_rms is only used in applications involving AC, usually with regard to audio amplifier max output. We are only interested in Watts as calculated by Joule's first law.


I would really like engineers with applicable experience (and proper equipment) to comment on this.

OK, thanks. If the iStick 30W works and displays power like most devices, then it's all good.

R

 

[tiburonfirst]

Yes, it is firing at 11watts. The new iStick30 appears to display V_rms and calculate Watts with V_rms. BIG improvement over the iStick20!! (I do not have a scope. I am basing this on an in-line voltmeter.)

I am not an engineer. I may be wrong. (Then again, an engineer may be wrong too.) But I've studied this a little bit. Just a bit. I was wrong to heap praise on donf99's OP without thinking about it a bit.

donf99 was wrong to refer to W_rms. It does not apply to DC or pulsed DC current. W_rms is only used in applications involving AC, usually with regard to audio amplifier max output. We are only interested in Watts as calculated by Joule's first law.


I would really like engineers with applicable experience (and proper equipment) to comment on this.

maybe bumping this thread will get somebody's attention

 

[VapingTurtle]

maybe bumping this thread will get somebody's attention

Ehhh... No need for a bump. I was right. No surprise. I'm always right.