Hi all,
I am building a robot, it is powered with two 12 volt batteries in series. The "brains" of the robot are a Raspberry Pi and an Arduino. The drive system is two stepper motors (Nema 34 size) that should be drawing 3.5 amps each.
Now that the robot is able to roam around and things are getting closer to putting this thing into action, I am trying to pay close attention to power draw, battery drain etc.
So, I connected my multimeter's RED probe up to the postive terminal of one battery (remember I have two in series), and connect the black lead up to the cable that would normally plug into that terminal on the battery. Set the meter to read AMPs, powered it up with just the logic and sensors active. It showed that it was drawing 0.97 Amps which sounds about right, no surprise there.
Then I repeated the test but also powered up the stepper motors/drives (Gecko). Oddly enough, the system is showing that it is only using 1 additional Amp with both motors powered. Knowing that the Gecko drive does go into a "Low power" mode, I then ran the steppers up to speed which showed it drawing yet another Amps (for 3 total).
I was expecting to see a current draw of 7 or 8 Amps.
Am I missing something in what I am doing?
For further information, there are inrush current limitting thermistors between the power source and the stepper drives which are 4 Amps Thermisters.
Chris D.
I am building a robot, it is powered with two 12 volt batteries in series. The "brains" of the robot are a Raspberry Pi and an Arduino. The drive system is two stepper motors (Nema 34 size) that should be drawing 3.5 amps each.
Now that the robot is able to roam around and things are getting closer to putting this thing into action, I am trying to pay close attention to power draw, battery drain etc.
So, I connected my multimeter's RED probe up to the postive terminal of one battery (remember I have two in series), and connect the black lead up to the cable that would normally plug into that terminal on the battery. Set the meter to read AMPs, powered it up with just the logic and sensors active. It showed that it was drawing 0.97 Amps which sounds about right, no surprise there.
Then I repeated the test but also powered up the stepper motors/drives (Gecko). Oddly enough, the system is showing that it is only using 1 additional Amp with both motors powered. Knowing that the Gecko drive does go into a "Low power" mode, I then ran the steppers up to speed which showed it drawing yet another Amps (for 3 total).
I was expecting to see a current draw of 7 or 8 Amps.
Am I missing something in what I am doing?
For further information, there are inrush current limitting thermistors between the power source and the stepper drives which are 4 Amps Thermisters.
Chris D.