How would I not blow up my Nano?

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.

Forget about how many amps the power supply can provide, how many volts are you supplying to the Nano ?

Originally it was 11.1 but I stepped it down to 7.4. It's a modified 3rd party board called the RF nano.

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.

  1. 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.

  2. 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.

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This is what I did. Everything is in parallel.

Does this mean that current isn't the problem?

I hesitate here because I don't know what you refer to when you say:

Does this mean that current isn't the problem?"

What problem are you referring to .

And a quick sketch will save a thousand words of description.

By "problem" I mean the issue that killed the Nano. If I can get rid of the issue I won't blow up the next one.

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

Would a table work? I will provide one. This is a combat robot by the way.

Start | End
Battery GND | Arduino GND
Battery GND | ESC GND
Battery GND | L298N GND
Battery VCC | Rocker Switch Pole 1
Rocker Switch Pole 2 | Arduino VIN
Rocker Switch Pole 2 | ESC VCC
Rocker Switch Pole 2 | L298N VCC
Arduino D3 | ESC Data
Arduino D4 | L298N IN1
Arduino D5 | L298N IN2
Arduino D6 | L298N IN3
Arduino D7 | L298N IN4
Arduino GND | ESC GND
Arduino +5V | ESC +5V (Unnecessary. Should be removed. I'll do that later.)
L298N M1+ | TT Motor 1+
L298N M1- | TT Motor 1-
L298N M2+ | TT Motor 2+
L298N M2- | TT Motor 2-

Onboard nRF24L01 connections

Start | End
nRF24L01 CE | Arduino D9
nRF24L01 CSN | Arduino D10
nRF24L01 VCC | Arduino +3V
nRF24L01 GND | Arduino GND

Rest of nRF connections are normal SPI.

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.

Everything is just shoved in the electronics box of the robot.

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.

I halfway wonder if the voltage regulator on the Nano just didn't like being at ~12V for five minutes straight.

I'll also try clipping any pins that I don't use to prevent shorts.

It is, especially because you did not properly format them for the forum (use of code tags might have helped or a markdown table).

Most people here will agree with you on Fritzing; they however will not agree with your statement on schematics.

Oh wow I forgot that existed.

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.

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