Choosing the right motor controller is one of the trickiest parts of building an RC tractor or robot or whatever you are trying to make. The reason is that a motor draws a lot of current which means the voltage the motor can handle might be small. This means you need to choose an appropriate battery to suit the motor but you also have to account for the voltage drop in the motor driver/controller chip. This is something I struggled with from the start and is the reason that my RC Massey 8680 model works on 7.4 volts and my RC Fendt 936 works on 3.7 volts.
The Massey has an L293D motor driver chip which I found to have considerable voltage drop at the outputs so when I used the 3.7 volt battery the motor barely turned and definately would not pull anyload behind the tractor. The massey uses a modified servo driver board which will work at the 3.7 volt however the board is not really designed for continuous rotation so you don’t have full control and the tractor can drift back and forth a little.
I would prefer to use single cell lipo batteries at 3.7 volts because they are small and I can run the arduino directly from the battery. I was actually just looking for an SMD alternative to the L293D chip when I found the TB6612 driver chip but as you see in the video this chip might solve my battery problems. The voltage drop on this chip is much smaller than any of the other chips I have used.
Here is the video and you will see that it powers the John Deere 9560R model from the 3.7 volt battery without much trouble. This is why I am going to try to run the John Deere 9560R model so keep tuned because I intend to record the John Deere build as a lot of people ask for a video of a build.
I hope you liked the video and if you have any questions post them here or preferably in the RC Tractors Forum as we’re still trying to build our community.