after running our robot for over half an hour we noticed that the motors in the front were running very hot, while the ones in the back were not even warm. it might be important to mention that most of the weight is in the front, and the motors are set off-center towards the back. perhaps this affects it?
It would be helpful to have a picture…
Some ideas: More frictional forces on the front wheels? Increased side loading on front wheels? Are you sure that back wheels are being driven at all?
In all honesty… I don’t think this is a **terrible **problem. 30 minutes is almost 15 times longer than you’ll run in a match. If you’re not tripping your circuit breakers, it’s unlikely that you’re pulling a dangerous amount of current.
And you’re correct that having more weight in the front affects the motor load. Your front motors are pulling more current and require more torque than those in the back.
Are you using the gearboxes supplied in the kit? If so, and you mean the front CIMs are hot, and the back ones are not, then most likely your Victors aren’t running/programmed properly.
I’m noticing a lot of teams (including ours) having a lot of difficulty properly connecting the PWM cables on the Victors. Check to see that when you are running the robot, that the Victors driving the back motors don’t have a flashing orange light. This means that they aren’t receiving a PWM signal from your robot controller. If they aren’t flashing orange, but are solid orange all the time, it means they are hooked up fine, but aren’t programmed to run properly.
If you are using the default code, you need to ADD code for two more PWM outputs to run all 4 motors, or use a PWM splitter cable to send the PWM signal to all 4 Victors.
I’m assuming you are running the kit drive with two CIM’s per side. Have you calibrated the Victors? To do so, remove the breaker for one of the motors and cal the other Victor of the pair on that transmission. Then repeat with the second one. The red and green “full throttle” LED’s on the Victors should come on together as you approach full throttle in each direction. As someone else said, if you have a blinking yellow on a Victor, that Victor is not getting a PWM signal and that motor will not receive power.
Thanks guys i checked the power output on two of the victors, turns out they didnt work, so my team replaced them and now we get much better battery efficiency and much more speed.
If anyone still has a problem you can try using fans or using passive cooling. Running the motors for 30mins is definetely a bit much, but at the competitions you will have plenty of time in between matches to let them cool naturally.
I would go with the fans,but like you said “Running the motors for 30mins is definetely a bit much” and it is. Heres what I would do, run your bot for 2 mins and 15 secs’ non-stop then touch the motor cases if there warm there fine, little over warm you have a problem.