Robot Brownout issues

Our robot tends to lose a lot of voltage after we start driving forward. We took off the pneumatic’s and the PCM could this be this issue? We have checked every connection, soldered the wire ends, and used lots of electrical tape. We checked every part of the robot and have stared at the diagnostics page on the driver station for quite a while trying to figure out why this keeps happening. Does anyone have an idea of why this is happening?

We can make a lot of guesses, which mostly involve asking you a lot of questions. If you can post some video of the robot to youtube or here, we might be able to get a better idea of the symptoms, then we can more likely guess what’s causing the problem.

Usually it’s just a discharged battery…but there are a lot of possibilities.

Yeah so we basically did the same thing you did to your robot but our robot is running Neos. I don’t know what kind of motors you are using but, in the case of the Neos it’s generally just a bad battery. I would use a battery Beak to test the battery health. Other than that I have no Idea. What kind of motors and controllers are you running?

I have seen this happen with a poor connection between a battery and the PDP. I would remove the electrical tape and make sure every connection is solid.

We are running VictorSPX’s with Cim motors

It would be a battery problem. I would use a fully charged battery and try again. How old is the battery and has it been used heavily?

Edit: I directed this at the wrong person It was meant to go to JAzZiBOi sorry.

Do a pull test on each and every wire, one at a time. All bolted connections should be tight enough that the lugs cannot be rotated with your fingers.

It might be related to this issue that your team had a few days back

Voltage drops can be caused by a few thousand different things. We can start asking randomly until we find the culprit, but it will be a lot faster if you can post your driver station logs here for us to see. That should help narrow the list a lot.

Also, post pics of your electrical board. There may be something that someone could spot with a fresh set of eyes.

What kind of drivetrain are you using? The Kit of Parts drive system? Or a custom one? What ratio is in your gearboxes and what diameter wheels? How many motors are in your drivetrain?

I would stress that you should make sure that your battery is fully charged and that it is a good battery to use. My team has done a lot with battery testing. You can find our info on it here is our battery report, the worlds presentation video and The worlds presintation slides If you have any questions feel free to ask me anything

Since you already had some other issue related to bad wiring, it would be beneficial to go to the FIRST website to find an established team and ask them to look over your robot. It is likely that they find the cause of your brownout issue as well as other issues that have not yet seen the symptoms of.

There are 4 motors in our drive train, 2 on the left and 2 on the right. We also have 2 motor controllers, 1 for the left and 1 for the right. We are using last years kit of parts from AndyMark.

This is not a competition legal set-up, although it is still functional and likely not the cause of your brownouts. CIM motors must each have their own motor controller and be connected to their own slot on the PDP in order to be compliant with the 2019 rules.

Everytime the voltage drops, we are trying to turn. It just seems like we only have voltage drops when we turn.

Yes we know. We have 6 motor controllers so we are using 2 for this demo/test robot and 4 for our competition robot

You’re going to have to look out for tripped breakers on your PDP if you opt to continue with this configuration. Even with a relatively conservative ratio selection, pulling two motor’s worth of current from a single PDP slot has the potential to trip 40A breakers.

Well at this point two cims are trying to share 40 amps, so that could be part of the problem.