Arduino and motor driver sharing a common battery supply

Hi,

I want to power my motor driver and arduino board using the same 12V lead acid battery. The current draw for the motors will be 6.8A and 18.6A for normal and heavy usage separately.

For a single power supply like this, do you know what components or circuits should I use to protect the arduino from the interference of the motor? Do I need to put a resistor in series with arduino to limit current or something else to prevent arduino from resetting when the motors draw a lot of currents.

I am pretty new to electronics and arduino. Please help. Many thanks.

You could use a diode and a capacitor. Or a DC-DC converter to make 7.5V for the Arduino. Or all three: a diode with a capacitor and a DC-DC converter.

With such currents and everything connected, you should know how the ground currents will go. The ground current from the motors should return into the motor driver and from there return to the battery. The current may not use a detour using the Arduino ground to go to the battery.

DCtoDC converter is a good recommendation. Also driving the motors with a relay or optoisolator/MOSFET combination is advisable, take your motor grounds to the battery terminal with a separate ground run for the Arduino. Use some sort of spark arrestor, MOVs diodes capacitors for the DC motors.

I want to power my motor driver

What motor driver ?

raschemmel:

I want to power my motor driver

What motor driver ?

It is Sabertooth Dual 25A Motor Driver.

Caltoa: You could use a diode and a capacitor. Or a DC-DC converter to make 7.5V for the Arduino. Or all three: a diode with a capacitor and a DC-DC converter.

With such currents and everything connected, you should know how the ground currents will go. The ground current from the motors should return into the motor driver and from there return to the battery. The current may not use a detour using the Arduino ground to go to the battery.

DC-DC converter is a good idea. My question is what happens to the output voltage when the input voltage is lower than the expected, say a DC-DC converter designed to accept 15v input and 12v output, if the input is lower 15v what voltage will it output?

I ask this question because we may also want the circuits can keep running when the batteries are being charged. I was thinking using a DC-to-DC converter to provide stable output when the charging clips are put on the batteries.

For a single power supply like this, do you know what components or circuits should I use to protect the arduino from the interference of the motor? Do I need to put a resistor in series with arduino to limit current or something else to prevent arduino from resetting when the motors draw a lot of currents.

The "interference" as you call it to the arduino from the motor is noise spikes. This can be greatly reduced by using a large electrolytic capacitor on the arduino +5V.