Oh!
Warning!
View attachment 414393
Well, let's see how to say this....
I failed with the same argument, using my voltmeters (analogue and digital). They cannot measure waves well....
They measure mean voltages (and currents) instead of Root Mean Squared (RMS) ones......
As the power goes proportional to the squared power of voltage (and current too), you need a RMS measure, which can only be obtained by oscilloscopes or devoted voltmeters (those Fluke with a tiny resistor inside, which compare the heat from the source and from a probe current internally fed).
Anyway, if you know the maximum (as peak) voltage of a squared-form output (like PWM outputs on the
istick-20W), it happens that V
RMS=V
peak/V
mean, and V
mean is probably that one that you get with your in-line voltmeter, or a normal voltmeter......
So, knowing that the peak voltage of the 20W is about 5,65 - 5,8 V (at full battery charge), it happens that your actual V
RMS when you set it at 3,0 V is about 4,10 - 4,15 V, which, just accidentally, is about the same that a full charged Li-ion battery (4,20 V)....
But it can go below battery output...they just put averages instead RMS on the chip, so they spoiled the chip capabilities with the software (and without upgrading available!).
As a matter of fact, the 20W does a hell of a job outputting a really steady voltage...it is just average instead the expected RMS.....
The 30W and the 50W output a sinewave-like but mostly like a DC flat, just curly or wavy (about a 5 % of wavy tops,and with a really high frequency) and in this case averages and RMS are, basically, the same, so they output real power, as they show it on their screens...
The 20W does show about 180 -190% of excess, at 3,0 V!
End of the.....
View attachment 414397
Sorry Folks!
