Are you trying to read voltage, amperage or watts? And why?
All three. And ideally Watt-hours too (1 digit behind decimal).
To measure the power consumption of devices (charging phones and powerbanks) while the engine is not runnung, and to monitor the voltage.
I already have USB chargers with voltmeter that can be put into a parallel circuit using an outlet hub, but I have to calculate for the resistance-induced voltage drop.
No read the amperage and voltage. E=I * R , R= E/I, I=E/R. Now to calculate power, in Watts. P = V * I = R * I2 = V2 / R. Which is simply P= V * I. In DC Voltage circuits. Now in AC Voltage its slightly more complex. But you don't need that in your car.
I know, but it is more convenient if the device calculates that for me in real time.
Also, I could monitor how much current the connected devices consume, to avoid drawing too much current (10A or 15A, depending on vehicle).
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