4 wheel chair motors connected to sabertooth 2x60 - stalls when turning skid steer style


I’m new to RC robot stuff and really hoping someone can help. I’m making a 4 wheel drive bot out of wood to push dirt. My setup is as follows:

  • 4 x 24V 250W wheel chair motors
  • 4 x 12V 35AH batteries connected in parallel and series
  • 1 x 12V 7.5AH to power the actuators and receiver
  • Flysky 6 channel remote
  • 2 linear actuators to control dirt pushing attachment, which is basically a snow plow.
  • Sabertooth 2x60
  • Sabertooth 2x12
  • Pollak Solenoid Switch
  • 2 x 40 amp fuses
  • Battery Switch, Briidea 12V-48V Battery Disconnect Master, https://www.amazon.com/gp/product/B08X1J3Z62/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

My wiring is essentially the same as the schematic shown in this tutorial for the snow plow robot: Tech Thursday #033: How to power a big electric motor – SuperDroid Robots

I’m using 10 AWG wires to go from the batteries to the motor controller. Then I have 14 AWG wires going from the motor controller to the wheel chair motors.

The sabertooth is operating in mixed mode to allow skid steering, so dip switches 1 and 5 are off. When I drive forward and backwards the system runs fine. When I turn right or left, the 2x60 stalls. The error light turns on and the status lights stays on. I haven’t connected the linear actuators to the receiver. I disconnected all switches and tried to run the system straight from the battery, but I received the same error. I’m not sure what is going on… thanks for any help!

@mybots Welcome to the RobotShop Community. If the motor controller stalls (as in, the current is higher than what it can provide), then indeed the motors are either not powerful enough for skid steering your robot, or they need a higher current than the Sabertooth can provide. Based on the data you provided, it seems like the wheelchair motors are 250W, and when operated at 12V, might consume up to ~20A peak. This is something which it seems like the Sabertooth should be able to provide, but note that even wheelchair motors are not meant for skid steering, so you might be maxing them out. Can you share a few photos of the setup?

Try it with just 2 batteries in a series 24v/35ah, are you able to measure the current?
How are your fuses installed? Should be between sabertooth and motor.

I’m guessing that you’ll need another 2x60, 2 batteries / 2 motors per sabertooth.