So I'm using LiPos to power my robot. There's a very slight problem.
I'm using the same power line to power a brushless motor and an Arduino. The problem arises when I turn on the motor.
The brushless motor draws huge amounts of power, around 20A. The problem is that the 20A power input from the batteries also goes into the Arduino because of the common power line.
Needless to say, a tiny regulator doesn't like amperages that are way over it's rating. The Nano proceeded to turn into a heating element, shorting out almost every part on the board.
How do I fix this issue? The problem with just using an absolute monster of a resistor is that the current input significantly drops when the weapon turns off, and then the Nano would have next to no input current due to the resistor.
The problem is that the 20A power input from the batteries also goes into the Arduino because of the common power line.
We need a quick sketch to be sure you don't have condition 1 below.
Drawing large current transients (slugs of current) will only effect your Arduino in two ways.
If the current is going through the Arduino board. I.e. power comes into one ground and out the other ground. Simply do not wire anything this way.
The current "slug" will temporarily reduce the voltage, maybe causing the Arduino to reset but will not damage it.
Recommended wiring of grounds:
The Motor should have a ground wire directly to the battery negative.
The Arduino should have a ground wire directly to the battery negative.
Same goes for the Positive power wires.
This is called a "Star" connection and it is the optimum method of connecting components, especially when some draw high currents.
OK so I'm hearing you had a setup wired, somewhere in your testing or operation the Nano died.
My guess is if you don't change something you will likely damage the next one.
Honestly, without a photo or sketch I don't have enough information to help you not damage your Nano's. Usually is simple to protect the Nano's but without knowing how you currently wire your project, its not possible for me to help. Sorry
EDIT - Maybe I'll make a Fritzing when I get home but I'm in Algebra 1 right now.
EDIT - To people unfamiliar with tables, this looks like a giant mess. I personally really like them. I find them much better than Fritzings, schematics, etc.
Tables don't do much for me because they don't show physical locations. I can look at a sketch and within a second see all I have to know. I personally can't do that with a table.
Finish your class, then it would be best if you sketched how it is connected on a piece of paper and took a photo and posted that.
Then sorry I can't help more. Perhaps you are getting an unintended connections (short). I suggest you inspect your wiring and look for areas a wire or device connection can touch something it isn't intended to.
Schematic diagrams make a lot of sense with circuits using a lot of basic parts. Here, I am using more parts without official symbols than ones that do, making any schematics pretty hard to look at.