Hello Felix, that was just an example trying to clarify the possible range of voltage level that my moteino is getting. My system does not have a drop from 5V to 1.7V over a night or two. I am sorry I didn't make myself clear about the choice of solar panel, scaps etc. I will explain that later (if you want).
What I am really trying to figure out is whether a moteino should turn back on automatically when the Vin raises and crosses (let's say) 4.0V? It is not about the solar panel only this phenomenon occurs in my LAB also. Let me explains my simple LAB set up (see circuit diagram below):
1. Two 3.0V 50F Scaps (in series) are powering moteino.
2. The +ve leg of the Scap1 is connected to Vin of the moteino.
3. The -ve leg of the Scap2 is connected to GND.
4. A 0-6V, 2.5A Agilent dc power supply is charging the scaps.
5. A 1 Ohm, 10 W power resistor is connected in between power supply and scaps.
Observations:
1. Moteino simply works fine when the voltage (Vin or Vc) is above ~3.3V.
2. I disconnect the power supply when the Vc reaches about 4.0V.
3. Then I discharged the scaps to about 2.9V using low-value high power resistor such as the one in the circuit.
4. After that, the scaps discharges rapidly itself.
5. When the Vc = 2.0V, the power supply is connected again.
6. Then the scaps start to charge again.
7. The moteino does not turn on even when the Vc reaches 2.7V, then to 3.0V, then to 3.6V and so on..
Questions:
1. Is this supposed to happen?
2. Why is this happening?
3. What should I do to turn it back on automatically?
Any suggestion, solution will be greatly appreciated.
Thank you