There's no doubt the regulator can handle a voltage up to 35V.
The problem as I see it is: since my supply is somewhat unstable and at times it constantly shifts in voltage this can confuse the Arduino reference values, particularly when using the 5V (I know this is the reason why Werk_AG has chosen to use the more stable 1,1V internal reference voltage instead for the Solar radiation part).
I have just tested and with an intermittent input voltage of 15,7-13,7 the regulator intermittently outputs 8,8 to 9,2 v.
Although most sensors claim to have internal voltage regulation of their own, I think that like with most anything overall my system would benefit from a more constant, stable power supply.
Interesting reference material I have found:
Voltage regulator tutorial & USB gadget charger circuit
A straight forward, clear Youtube video explaining how linear regulators work and how to connect them.
How to Connect a Voltage Regulator in a Circuit
More on the matter but in text form.
Secret Arduino Voltmeter – Measure Battery Voltage
An interesting post on how Arduinos handle voltage.
I quote:
"A common assumption when using analogRead() is that the analog reference voltage is 5.0 volts, when in reality it may be quite different (...) The fact is the default analog reference is not 5.0 volts, but whatever the current level of Vcc is being supplied to the chip. If our power supply is not perfectly regulated or if we are running on battery power, this voltage can vary quite a bit"
Arduino misconceptions 6: a 9V battery is a good power source
Argues that using a 9v power source to power an Arduino may not be the best solution.
Ideally, perhaps we could skip linear regulators all together and use something like these DC/DC converters (they can be used in the current boards/design already since they fit the TO-220 footprint) to power the Arduino from a lower voltage and either power the fan independently 24/24h or use some sort of switch to act upon an independent 12v circuit?
The problem as I see it is: since my supply is somewhat unstable and at times it constantly shifts in voltage this can confuse the Arduino reference values, particularly when using the 5V (I know this is the reason why Werk_AG has chosen to use the more stable 1,1V internal reference voltage instead for the Solar radiation part).
I have just tested and with an intermittent input voltage of 15,7-13,7 the regulator intermittently outputs 8,8 to 9,2 v.
Although most sensors claim to have internal voltage regulation of their own, I think that like with most anything overall my system would benefit from a more constant, stable power supply.
Interesting reference material I have found:
Voltage regulator tutorial & USB gadget charger circuit
A straight forward, clear Youtube video explaining how linear regulators work and how to connect them.
How to Connect a Voltage Regulator in a Circuit
More on the matter but in text form.
Secret Arduino Voltmeter – Measure Battery Voltage
An interesting post on how Arduinos handle voltage.
I quote:
"A common assumption when using analogRead() is that the analog reference voltage is 5.0 volts, when in reality it may be quite different (...) The fact is the default analog reference is not 5.0 volts, but whatever the current level of Vcc is being supplied to the chip. If our power supply is not perfectly regulated or if we are running on battery power, this voltage can vary quite a bit"
Arduino misconceptions 6: a 9V battery is a good power source
Argues that using a 9v power source to power an Arduino may not be the best solution.
Ideally, perhaps we could skip linear regulators all together and use something like these DC/DC converters (they can be used in the current boards/design already since they fit the TO-220 footprint) to power the Arduino from a lower voltage and either power the fan independently 24/24h or use some sort of switch to act upon an independent 12v circuit?