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### Topic: 28byj-48 stepper motor power consumption? (Read 2255 times)previous topic - next topic

#### ObiTewodros

##### Apr 12, 2016, 08:47 pm
I am using 6 1.5v AA batteries to power the stepper motor. The 6 batteries are only used to power the stepper motor. This is how I wired everything up:

I use the custom stepper library from the following link:

http://makecourse.weebly.com/week8segment2.html

The 6 batteries were empty after about an hour of the motor rotating at 10rpm. Is this normal? Seems very fast to me.

Is there a way to calculate how long the battery will last?

#### jremington

#1
##### Apr 13, 2016, 05:11 pm
Quote
Is this normal?
Yes.

To calculate how long (in hours) the batteries will last, divide their capacity (in mAh) by the current draw (mA).

#### MarkT

#2
##### Apr 14, 2016, 10:59 pmLast Edit: Apr 14, 2016, 11:00 pm by MarkT
The motor is normally rated at 5V and 70 ohms, so each winding will take 70mA with one
winding active, 140mA with two (some step patterns like full-wave do this).

At 9V supply those values will be 130mA and 260mA instead, and you will overdrive the motor.

The first thing to do is use just 3 or 4 batteries, not 6, for the motor, that will extend life by a
factor of two-ish.

Secondly find out which step pattern is being used and change to wave drive if not already,
which is the least power-hungry.

Stepper motors are never a good choice for battery power, they take lots of power even
when stationary.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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