Operational Requirements

Main Power

Refer to the model-specific datasheet to confirm RoboClaw’s minimum and maximum input voltage. Standard models typically operate from 6 VDC up to 34 VDC; High-Voltage (HV) variants operate from 10.5 VDC to 60 VDC. Connect power to the terminals labeled “+” (positive) and “-” (negative). Keep battery wiring as short as possible to reduce inductance and minimize voltage spikes.

Reversing main power polarity will cause permanent damage to the controller.

Emergency Stop

The motor controller should be wired with an external contactor, relay or high-amperage mechanical switch on the main power input. This allows the system to remove power quickly in the event of a malfunction or runaway condition. The device used must be rated for the full battery voltage and current.

Safe Disconnect

Only the positive lead should be disconnected. Do not disconnect the negative lead if any other ground-referenced connections, such as USB or signal grounds, are still attached. Disconnecting only the positive lead ensures a safe power-down without creating unwanted return paths through other equipment.

Do not disconnect the battery negative wire if other ground sources are connected, such as a USB cable. Damage will occur.

Motor Wiring Guidelines

Motor terminals are labeled M1A / M1B for channel 1, and M2A / M2B for channel 2. In differential-drive systems, reverse the wiring on one motor so both rotate in the “forward” direction when using mixed-drive commands.

Use proper ring terminals for power and motor connections. Crimp securely and torque tight enough to maintain solid contact under load. Keep motor and battery leads as short as possible; long wiring increases inductance and can lead to harmful voltage spikes when current changes abruptly.

Fuses

Protecting the power path with a fuse is important for system safety. A properly chosen fuse helps protect downstream electronics, wiring, and the power source (such as a battery) from excessive current. However, a fuse may not prevent damage to the motor controller itself in all fault conditions. It is primarily a safety device.

Selecting a fuse for motor systems is not trivial. The fuse must carry the normal running current while tolerating short-duration surges such as startup or stall current, without opening prematurely. Time-delay (slow-blow) or motor-rated fuses are generally recommended for this purpose.

Fuse Selection Guidelines

  • Time-Delay vs Fast-Acting: Motors draw high startup and stall currents. Use a time delay (slow-blow) or motor-rated fuse to survive brief surges. Standard fast-acting fuses may open during normal startup.
  • Sizing: A fuse should be rated above the motor’s normal running current (often 120% or more) to avoid nuisance trips, while still protecting against faults.
  • Trip Characteristics (I²t): Fuses respond non-linearly; large surges clear quickly, smaller overloads take longer. Select a fuse whose I²t curve matches expected motor surges.
  • Temperature Effects: Fuse ratings change with heat. Check datasheets for derating information when operating in warm environments.

Power Supplies

RoboClaw is a regenerative motor controller. When a motor brakes, slows or coasts, it generates energy. When using a power supply, the regenerative energy has nowhere to go. If it is not managed, the voltage can rise and damage the motor controller, the power supply or both. Regenerative energy can be handled in several ways. The two most common are adding a battery in parallel with the power supply, or clamping the excess energy and converting it to heat using a high-watt resistor. The VClamp is a ready-made clamping solution.

Regenerative energy can result in damage to the motor controller if left unmanaged.

Current Reporting

External instruments such as digital multimeters and programmable power supplies typically measure and display RMS or time-averaged current over much longer integration periods (seconds). As a result, their displayed values may differ from the controller’s reported current.

The motor controller measures phase current by taking samples during the PWM “on” interval. Each reading is averaged over roughly 50 milliseconds and represents the instantaneous current during that sample period. Minimal filtering is applied to maintain a fast response in the control loop.

Users may apply additional software filtering or averaging to sequential motor current readings, or rely on external instrumentation designed for long integration periods.

Motor Current vs Battery Current

Motor current will not be equal to battery current. When operating below 100% duty, the motor only receives a fraction of the battery voltage during each PWM cycle. To produce the same torque at a lower effective voltage, the motor draws higher current than the battery. The bulk capacitance on the motor controller and the motor windings store and recirculate energy during each PWM cycle. As a result, the battery supplies only the average current, while the motor sees short, higher current pulses. For example (examples assume a 24V main battery):

  • 25% duty: motor ~6V, about 4× battery current
  • 50% duty: motor ~12V, about 2× battery current
  • 75% duty: motor ~18V, about 1.3× battery current

ESD Sensitivity

RoboClaw utilizes a high-performance processor that can be susceptible to electrostatic discharge. The I/O and control signals are protected, but static can still be introduced into unprotected areas, such as the motor terminals, when wiring or handling the controller. Avoid handling the PCB unnecessarily and ensure any static charge is discharged before working with RoboClaw.

Static sensitive device. Handle with care.

Environmental Conditions

RoboClaw motor controllers are not rated for direct exposure to moisture, condensation, corrosive agents, or extreme ambient temperatures. It is the end user’s responsibility to evaluate the expected operating conditions and provide appropriate protection such as enclosures, ventilation, or environmental controls when required. Proper mitigation will help ensure reliable long-term operation.

Motor Specification

When pairing a motor controller with motors, it is important to know the motor’s stall current and continuous current ratings. These values determine how much current the motor will draw under different operating conditions. The stall current defines the maximum current the motor will demand at startup or when it cannot turn, while the continuous current specifies the safe, long-term operating level. Matching these values to the controller ensures that the motor can run reliably without overloading or damaging the controller. Using a controller that is undersized may lead to overheating, shutdowns, or permanent failure.

Stall Current

Stall current is the maximum current a motor will draw when it is not turning. This happens at startup, or if the motor is held in place and unable to rotate. Every time a motor starts, it briefly pulls its stall current until it gets moving. A motor controller must be able to handle this surge of current, even if it only lasts a short time.

Continuous Current

Continuous current is the maximum amount of current a motor can safely draw while running without overheating. This value reflects the motor’s normal load-carrying ability during sustained operation. The motor controller continuous current rating should be equal to or greater than this rating. If the motor controller is undersized the system may experience overheating, reduced performance, or shutdown.

Wire Lengths

Keep all motor and battery wire lengths as short as possible to minimize inductance. Excessive wire inductance can generate voltage spikes beyond RoboClaw’s rating, leading to component failure.

Run Away

During project development, take precautions to prevent uncontrolled motor operation. Keep robot wheels elevated and clear of all surfaces until development and testing are complete. For embedded motor applications, ensure a readily accessible method of power disconnection from the RoboClaw is available as a fail-safe measure.

Powering External Devices

When powering external devices from RoboClaw ensure the maximum BEC output rating is not exceeded. Exceeding it can cause RoboClaw to suffer a logic brownout, which will cause erratic behavior. Some encoders can put excessive noise on the +5VDC rail of the RoboClaw. This excessive noise will cause unpredictable behavior.

Encoders

RoboClaw features dual channel quadrature/absolute decoding capabilities. Signal noise on encoder lines can cause erratic behavior or position errors. Install appropriate filtering circuits to ensure reliable encoder operation. When connecting encoders, verify that the encoder’s directional output matches the motor’s rotation direction. Incorrect encoder connections can result in uncontrolled motor operation. See the Encoders chapter of this manual for detailed setup instructions and recommended filtering configurations.

Data Sheets

Please refer to the data sheet for the specific model of RoboClaw being used. The data sheet contains information specific to each model of RoboClaw. This manual is a general overview of RoboClaw usage and does not contain detailed information such as pinouts for each model of RoboClaw.

Example Libraries

Official Basicmicro libraries are available to streamline development and provide reliable communication using the Packet Serial protocol. These libraries handle CRC generation, byte formatting, and packet structure, allowing development with simple, high-level functions instead of low-level serial code.

Libraries are provided for the following platforms:

  • Arduino (C++): includes functions like SpeedM1() and ReadEncM1() for direct motor control and encoder access
  • Python (Raspberry Pi, Linux, macOS, etc.)
  • ROS2

The Arduino library installs through the Arduino Library Manager (search for “Basicmicro”). Libraries can also be downloaded from the BasicMicro downloads page, and source code is available on GitHub. Additional tutorials, wiring guides, and usage examples can be found at resources.basicmicro.com.