On a Suzuki gs 550 motorcycle battery reads 12.6 Volts DC when the motor is off. But when I start the motor, digital voltmeter reads zero. I have never seen this before. Any ideas?

  • 3
    Reads where, measured how, at what exact condition? When it is driving a load voltage drops
    – PlasmaHH
    Nov 5, 2017 at 18:26
  • Are you sure you are reading the voltage across the battery terminals? It sounds like a measurement problem.
    – Kevin White
    Nov 5, 2017 at 19:22
  • what @PlasmaHH said is right.Without knowing the exact way you are measuring we can't say for sure. Also, zero volts means a dead short which sounds kinda impossible in your case.
    – Rahul Salin
    Nov 5, 2017 at 19:24

1 Answer 1



You probably measured the voltage across a switch as shown in (a).

  • When the switch is open you get full battery voltage reading.
  • When the switch is closed the meter is shorted out so you get a zero reading.

Try measuring as shown in (b).

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