Using the AutoPi With an External Power Supply

This guide is applicable to the following device / devices:

TMU CM4

CAN-FD Pro

CAN-FD Pro +IP67 casing

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AutoPi devices are preconfigured for in-vehicle use. For lab or bench setups, you can safely power the device with an external power supply through the OBD connector.

Recommended for testing and troubleshooting

Using an external power supply is an excellent option when validating configurations, reproducing issues, and troubleshooting behavior outside a vehicle.

Setup Checklist

1. Always power the AutoPi through the OBD connector. Do not use the Raspberry Pi power inputs. This can cause AutoPi features to behave incorrectly and may damage the device.

2. Use a stable power source. AutoPi may power down automatically when voltage drops below 12.2 V to protect the vehicle battery. For lab use, provide at least 12.5 V and use a power supply rated for at least 2.5 A.

3. Be aware of sleep timer behavior. If no communication is detected on the vehicle CAN bus, a sleep timer may be triggered.

Useful Commands

You can run AutoPi Core commands either locally on the device or over SSH, read more here: How to SSH to Your Device.

• Local terminal format: power.status.
• SSH format: autopi power.status.

The autopi prefix works for all AutoPi Core commands. See the commands documentation for a full reference.

Sleep Timer Commands

Sleep timers are power-management timers that can put the AutoPi into sleep mode when no expected activity (such as CAN bus communication) is detected for a period of time.

• To inspect sleep timers, run power.sleep_timer.
• To clear all timers, run power.sleep_timer clear=*.

Read more in Power Sleep Timer Commands and the Sleep Timers Guide.

Recommended Cable

For an easier connection to an external power supply, we recommend the OBD power cable available in our shop: OBD-II Power Cable.