I am building a rover, that ideally I would like to power from a single 12V Marine Battery. The battery provides power to all the components:

  1. Pi3 through a Power Converter

  2. 12V LED computer monitor, draws about 2A.

  3. 4 hobby motors - each draws about 60 watts.

Everything works fine - until I engage the motors through automotive relays - it causes the monitor to restart. The PI seems unaffected.

My thought is that the current draw from the 4 motors engaging draws too much current and causes the monitor to have to restart.

I thought that putting a capacitor across the battery might work - as that is what I would do to prevent disruption to a high end sound system due to momentary power draw. But that did not seem to have any effect.

I can't imagine this is good for the PI either.

  • First step: measure the voltage across the battery with all motors engaged. It might drop below the threshold the display requires to work whereas the Pi is unaffected since its 5V comes from the voltage regulator that has plenty of headroom even if the battery's voltage drops a few volts (input voltage 8 to 40 V). Feel free to add your findings directly to your question using the "edit" button. – Ghanima Dec 27 '17 at 23:36
  • Thanks for your attention!! When the rover is just in standby the voltage reads 12.5, when the motors are engaged it drops to 11.9, and stays there until the motors are stopped. – rgrutko Dec 27 '17 at 23:46
  • Ok, so voltage drop is not an issue. You'll need to investigate decoupling of the power supply which is not related to the Pi and might be served better on electronics.stackexchange.com – Ghanima Dec 27 '17 at 23:54

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