voltage and accuracy

[legosteam]

We are using the pybricks blocks. One of our students was working on a long FLL run solving several missions. The beginning was working every time and she was making small changes on the back end. After at least a dozen successful tweaks the beginning started acting differently without any change to the beginning code. We checked the robot thoroughly for physical problems and found none. Testing the battery voltage showed it was around 7500 mV. We primarily use the basic turn for degrees and straight for distance blocks. Is there any reason a lower voltage would affect how these perform? We had the idea of setting the voltage maximum for each motor to 7400 and having the hub light up red when the battery is below this threshold. Will this make a difference to performance? Thanks in advance for any info and suggestions!

[laurensvalk]

What kind of changes were you seeing? Did it go back to the original behavior after charging?

A lower battery could have an impact if your robot is operating very close to top speed or with high loads (where it needs all the power it can get). If that is the case, lowering the speeds could be an option too.

[legosteam]

It was not going its full distance in the middle of the run. This was the end of yesterday's practice, we will test it on a full battery tomorrow. We do have a high load because of a large attachment and i will check our speed with the student. Do you think lowering our voltage max to do all our coding would get us more consistent results over a longer period of time?

[laurensvalk]

If it isn't going full distance, I would probably recommend digging a bit deeper into the design and code fundamentals rather than tweaking things like voltage settings 😊 Save yourself a lot of trouble down the line.

Try to boil it down to the smallest program that reproduces the issue, and then look at exactly where it is stopping, and why. (This is a great learning opportunity for the kids too. Don't forget to document the process so they can talk about it during the design review or presentations.)

[legosteam]

Thanks, we will look into this further using your suggestions in our practice tomorrow.