I want to use the Arduino to control various electronics on my motorcycle. I would need to power the Arduino with the motorcycle battery. So the question is, when the motorcycle is running the alternator will be putting out something like 13v to the battery. So can I still just connect the battery directly to the vIn and ground to power it?
Automotive power has a lot of noise and high transients in them. The Arduino a power circuitry has no protection against this. I'd suggest getting the circuitboard out of a cheap car-sigaret to USB power supply and using that.– GerbenMar 30, 2017 at 14:14
an LM7808 would take a lot of pressure and heat off the internal LDO while regulating noisy 12v– dandavisMar 31, 2017 at 3:38
Accordly to Arduino Technical Specs:
-Input Voltage (recommended) 7-12V
-Input Voltage (limit) 6-20V
Another Arduino thread: https://forum.arduino.cc/index.php?topic=22676.0
I would say a better choice is to use another battery power supply just for Arduino. Is is easy to install, easier to handle and more verstile unless you really needs to use your motorcycle battery. And if you want or need to read your motorcycle battery just use a portable voltage meter plugged onto Arduino with no need to use your vehicle battery to power it.
1“Arduino need an DC input of 5 volts”: the Vin input is spec'd to take from 7 to 12 V. Mar 29, 2017 at 19:16
For sure, I misundestood. Vin not USB. Im going to fix my answer Mar 29, 2017 at 19:22
Just add a rectifier diode or two before the vin input. This gives you a 0.7V drop per diode for large currents, for small currents the LDO won't overheat anyway...