Issue with powering four 5V DC motors

[randomuser4638]

I am using two motor drivers from sparkfun (SN754410 which is a replacement for a L293D) to control four 5V dc motors using a battery pack of four AA batteries. When I started test running some simple code to move the robot using the Arduino IDE, I notice that sometimes the motors would get stuck and not move when placed on the floor. This isn't an issue when I lay the robot on its "back" since all the motors run fine in that configuration.

I believe that the h bridge motor drivers lowers either the voltage or current (maybe both) so I'm trying to find an alternative right now to fix this issue of stuck motors whether it be a different source of power such as LiPo.

Any advice on how to fix this issue since I'm using this robot for path planning and I don't want the robot to drift from its assigned course.

Additional Information:
I am separately powering the arduino using another four AA battery pack so its not supplying the power to both motors and arduino.

There could also be an issue with weight(?) since I have everything on top of the robot.

[Klaus_K]

Not all batteries are created equal. Measure the voltage across the output of your batteries with a multi-meter when your motors are off and compare it when you switch them on.

[gilshultz]

What you are saying about the robot makes perfect sense, that is caused by insufficient drive to the motors. Start by looking for a MOSFET output H bridge. The SN754410 has an approximate 2V drop which is dependent on the current. Short term increase the motor voltage. Be sure all the grounds are connected. If you are concerned about the hookup post a schematic, not a frizzy drawing.

[DaveWreski]

Please use the new replacement dual MosFet version. Almost no voltage drop.
TB6612FNG Dual Motor Driver Module PWM.
Less than $3.00 new. Works Great too !

[gilshultz]

Great choice! Surprising what a lower voltage drop will do:-)