Answers.Body: <p>Some possible reasons:</p>
  
  <ul>
  <li>A motor is defective</li>
  <li>One of the brick has lesser battery charge</li>
  <li>Firmware problem: make sure both bricks have latest firmware</li>
  </ul>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-12-02T00:39:59.857Z
Answers.Text: it was the battery.
Answers.UserDisplayName: Lori
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-11-24T15:13:52.250Z
Answers.LastActivityDate: 2017-11-24T15:13:52.250Z
Answers.UserDisplayName: Vikhyat Agarwal
Body: <p>I have two identical box designs with EV3 bricks.  When I upload the same programs to both, one moves about twice as fast as the other. </p>
  
  <p>Is there a reason that this might be happening?  Is there anything I can do to update it?</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-12-02T00:39:21.153Z
Comments.Text: So it turns out the issue was a bad rechargeable battery pack.  When I replaced with fresh batteries the robot performed comparably to the other.
Comments.UserDisplayName: Lori
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-11-20T19:45:00.197Z
Comments.Text: Have you checked the batteries? Maybe one has almost-dead batteries?
Comments.UserDisplayName: Alexander O'Mara
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-11-20T19:59:29.127Z
Comments.Text: I have fully charged both batteries and they are both reporting full batteries.  I will try to swap out the batteries but right now it's not easily accessible from the design I've got, so I was just curious if this was expected or not.
Comments.UserDisplayName: Lori
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-11-20T20:11:14.793Z
Comments.Text: Can you post your program, or at least the part with the Move blocks?
Comments.UserDisplayName: David Lechner
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-11-20T20:53:29.250Z
Comments.Text: It's noticeable on a standard steering block - say at 75 power and going for a few rotations - on one brick that move may take a second, on the other, 2 seconds. i'll run and time it later today and post specific times, wheel diameters and rotations.
Comments.UserDisplayName: Lori
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-11-21T13:18:13.143Z
Comments.Text: Are you sure the problem is with the ev3 bricks? Have you tried switching the motors? Maybe one is defective?
Comments.UserDisplayName: Phil B.
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-11-21T13:29:20.357Z
Comments.Text: I didn't swap the motors, but if one of the motors was defective, on a tank steering block I would expect that if both motors were at the same power it would turn because one motor would be outputting power at a different level.  Given that it goes straight, it would mean that both motors are sending the same output.
Comments.UserDisplayName: Lori
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-11-24T15:08:17.663Z
Comments.Text: Is it possible you have more tension or friction in one of the builds? I assume that you've got some gears, etc in there - are they all able to spin freely, or are some of them clamped a bit tighter? I agree this is probably unlikely based on your comment about "tank steering" as that would required the two sides to be equally stiff.
Comments.UserDisplayName: Zhaph - Ben Duguid
Tags: <ev3>
Title: Why do two EV3 bricks have different power outputs?
UserDisplayName: Lori
ThreadText: # Why do two EV3 bricks have different power outputs?
  
  (Asked by: username_0 on 2017-11-20)
  
  I have two identical box designs with EV3 bricks. When I upload the same programs to both, one moves about twice as fast as the other.
  
  Is there a reason that this might be happening? Is there anything I can do to update it?
  
  **Tags:** ev3
  > **Comments:**
  > **username_1**: Have you checked the batteries? Maybe one has almost-dead batteries?  
  > **username_0**: I have fully charged both batteries and they are both reporting full batteries.  I will try to swap out the batteries but right now it's not easily accessible from the design I've got, so I was just curious if this was expected or not.  
  > **username_2**: Can you post your program, or at least the part with the Move blocks?  
  > **username_0**: It's noticeable on a standard steering block - say at 75 power and going for a few rotations - on one brick that move may take a second, on the other, 2 seconds. i'll run and time it later today and post specific times, wheel diameters and rotations.  
  > **username_3**: Are you sure the problem is with the ev3 bricks? Have you tried switching the motors? Maybe one is defective?  
  > **username_0**: I didn't swap the motors, but if one of the motors was defective, on a tank steering block I would expect that if both motors were at the same power it would turn because one motor would be outputting power at a different level.  Given that it goes straight, it would mean that both motors are sending the same output.  
  > **username_4**: Is it possible you have more tension or friction in one of the builds? I assume that you've got some gears, etc in there - are they all able to spin freely, or are some of them clamped a bit tighter? I agree this is probably unlikely based on your comment about "tank steering" as that would required the two sides to be equally stiff.  
  > **username_0**: So it turns out the issue was a bad rechargeable battery pack.  When I replaced with fresh batteries the robot performed comparably to the other.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_5 on 2017-11-24. Score: 2 | Accepted answer
  
  Some possible reasons:
  
  * A motor is defective
  * One of the brick has lesser battery charge
  * Firmware problem: make sure both bricks have latest firmware
  
  > **Comments:**
  > **username_0**: it was the battery.  
  
  ---
  
  