General discussion • Re: Powering RPi 3B in a remote area

We really need to be careful about the units here. Errors in the units will hinder understanding of the underlying physics and how the calculation works.

You know your amps, 2.5, and you know your volts, 5.1 which gives us 12.75w,

Correct so far. The w for Watts should be capital W.

so watt hours is 12.75 if I am figuring this correctly.

You are not. You can't convert watts to watt hours until you specify the period of time.

We have commonly established fact that 3 days is equal to 72 hours more or less.

Why make a big deal of this?

We can quibble about the time it takes to make the leap year but I honestly don't care...

Utterly irrelevant. More concerning would be the +/- 1 hour caused by the change to or from summer time. But even that only happens twice a year.

Anyway, so yes your math adds up, 918w/hrs consumed.

The maths is correct, but the unit is a watt hour (power multiplied by time, Wh), not a watt/hour.

Now are you tapping directly off of say a 12 or 24 volt battery, or will you be using an inverter as inverters eat up a bit of power, let's be cautious and say for 3 days your combined power total need is 1100 w/hrs.

Apart from the same mistake again in the name of the unit, we're back on track.

Statistics: Posted by davidcoton — Fri May 03, 2024 8:20 am

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