I am new to the Moteino world and I was hoping someone could help me with the range of voltage that can be used to power the Moteino. This
https://farm4.staticflickr.com/3818/10585364014_df2e1604bc_o.png
Says VIN can be 3.3V to 9V. But the specifications page
https://lowpowerlab.com/guide/moteino/specifications/
Says 3.6V-16V (up to 12V recommended).
I need to power it either off of 3.3V or off of the battery voltage (12.6V) and depending on which specification is correct I should be ok. Thank you.
lemmy, this will depend on what your software gets the moteino to do.
If you put 12.6v into the regulator on the moteino, with 3.3V out, thats 12.6-3.3=9.3V across the regulator.
It the radio is running...and the moteino runs at usual speed... probably draws about 25mA. So the regulator gets to dissipate 25mA * 9.3V = 232mw.
The regulator is probably about 70 degrees C per watt junction to ambient,, so that implies it will get to about 0.23 * 70 = 16 degrees C above ambient. Which is not really a problem.
So unless you are running the moteino really fast or really hard in a hot ambient, no issues.
You can also run the thing off 3.3 and connect it to the pin labelled 3v3. Lower power and less self heating in applications where you might want to measure temperature (say)
The regulator is rated up to 16V Vin, the issue is more how well it is cooled. It needs a tiny bit or airflow over the board to dissipate a quarter of a watt.
Different variants of the MCP170X regulator were used over time. In the first revisions it was up to 9V. Now it can go up to 16V according to Microchip.
I would not put more than a constant 12V on the VIN though. The lower, the better and more efficient it will be, but at 12V or more you're probably not concerned with battery life or efficiency.
Anyway I recommend not more than 12V, use some diodes if you have to step it down a bit from a higher voltage.