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Cranking amps
- Thread starter lgpjr49
- Start date
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You can take a clamp meter and clamp the end around the positive cable going to the starter then crank the motor. It may be kind of hard to tell just how many amps it is taking because it happens so fast and the meter may not show the max amps it recorded while it was cranking. If you have a clamp meter that has a Min/Max function it will be easier to tell the max amps that it recorded to start your motor. The thing is these meters are kind of pricey.
Very tough question to answer. The amperage is going to be ALL over the place when you start. Things that will affect it:
Battery voltage - Higher voltage will cause the motor to draw less amps to do the same job.
Ambient temperature - Cold starts will draw more, as motor parts will be reluctant to move quickly,
Starter temperature - As starter temperature increases, resistance within the starter will increase,
Wire gauge - smaller wires will reduce the voltage to the starter, causing it to draw more amps to perform the same job,
Even with all of the above issues remaining consistent, the draw within one start cycle will vary significantly too. The inrush current to start the motor turning will likely be your highest draw, but every time one of the pistons reaches the compression stroke, the starter will work harder too.
I doubt that any electronic multi-meter would be able to keep up with the fluctuations.
best way to determine would be to see if a spec exists on the starter motor itself. That should give you an idea.
Now, after all of that, from what I can see on various searches, it appears to be somewhere between 100 and 150A running current with a very short duration spike during the inrush of about 400A.
Good luck!
Battery voltage - Higher voltage will cause the motor to draw less amps to do the same job.
Ambient temperature - Cold starts will draw more, as motor parts will be reluctant to move quickly,
Starter temperature - As starter temperature increases, resistance within the starter will increase,
Wire gauge - smaller wires will reduce the voltage to the starter, causing it to draw more amps to perform the same job,
Even with all of the above issues remaining consistent, the draw within one start cycle will vary significantly too. The inrush current to start the motor turning will likely be your highest draw, but every time one of the pistons reaches the compression stroke, the starter will work harder too.
I doubt that any electronic multi-meter would be able to keep up with the fluctuations.
best way to determine would be to see if a spec exists on the starter motor itself. That should give you an idea.
Now, after all of that, from what I can see on various searches, it appears to be somewhere between 100 and 150A running current with a very short duration spike during the inrush of about 400A.
Good luck!
