Hi everyone - I’ve been working with robotics for the past few months to learn the basics of electronics, and how to use a microcontroller to control motors.
I am currently working on modifying the electronics in a Power Wheels ride-on car to make an autonomous vehicle; an ultrasonic distance sensor will send signals to an Arduino Uno, which will then regulate motor speed and direction. I’ve worked with small motor drivers in the past, but for this project, I will need to use something much bigger.
Currently, I am planning on using the two 12V DC motors that came with the Power Wheels car, and wiring them into a motor driver that I will use with the Arduino. The main goal I have is autonomous movement of just the vehicle, but I may attempt to modify the electronics so they can successfully move a passenger in the car forwards. As of right now, I’m planning on using Pololu’s Dual G2 High-Power Motor Driver 24v18 Shield for Arduino.
Is there any way I can determine how much weight this motor and driver combination can move, or at what speed? I would use a 12V SLA battery as a power supply for the shield and motors, and would expect this vehicle to drive mainly on flat, level ground. If I decide to include a passenger, I may have to upgrade the existing motors and power supply to 24 Volts - could I use a similar Pololu motor shield to achieve this? I’m unsure if this motor shield would meet the current requirements of my motors.
Thank you very much for taking the time to help me as I start exploring more complex motor drivers - it really means a lot to me!
Hello,
Without knowing the specs of the motors used in your Power Wheels car (particularly the stall current), it is hard to say if the G2 High-Power Motor Driver 24v18 is appropriate. I have seen people use 23A and 25A drivers, but they might have different motors if they have a different model.
You might try doing some internet searches to see if someone has done a similar project and see how much current the drivers they used can handle, then compare that to our High-Power Motor Drivers.
Please note, our G2 High-Power Motor Drivers do have a current limit feature which could be helpful in protecting those drivers against current spikes, so you should consider setting that limit to an appropriate value for the motors you are using.
If you do find some information about the stall current of those motors, I would be glad to take a look and see if I can offer some suggestions.
-Derrill
Hello - thanks for the advice!
I’ve found a link to the motors in this Power Wheels car, and posted it below. It appears that stall current is 61 Amps, but I haven’t found any other similar projects that use motor drivers at this level of current.
I’ve done some research, and found a similar project that advises using a motor driver of at least 25 amps alongside a 25 amp fuse connected to the battery. Would a fuse provide enough protection in the event of a current spike?
Adding a fuse is a good plan. If you use some acceleration limiting and set the current limit, you might be able to use our G2 High-Power Motor Driver 18v22 Shield which can handle a little more current than the 24v18 model.
Alternatively, you might consider the RoboClaw 2x60 which should be able to handle even the stall current of that motor.
If you change your system to run off 24V, you might need to re-evaluate your motor driver choices.
-Derrill
