3.25 in turbo base?

we have a 3.25 in 4 motor turbo base on our robot, and we are constantly having stalling problems, we are using bearings and chaining the front motors to the back motors. We have all 4 motors on our power expander, and on full battery, it blinks green and then goes btwn red and green, I belive we also have slew rate control.

Could this be fixed with code or changing it to high speed? Or do we need a new power expander?


we also have distributed the motors to have 2 on base and 2 on cortex

With that ratio and wheel size, you’re going to have burnout issues on your drive unless your robot is extremely light and your drive is nearly frictionless. Even then, when turning or driving with objects you will have issues with burning out. You shouldn’t burn out if you do high speed gearing on 4-inch wheels, and definitely not if you do high speed on 3.25-inch wheels.

I haven’t mastered all the tricks, but I’d say you will have trouble not burning out on that ratio no matter what you do.

Dont put all four on the power expander, then go on a diet.

You should probably try to move everything on the drive to the cortex and probably put 2 of your lift and claw on the power expander. Since you will be driving with heavy loads and need power I’d suggest that. We have 4 inch turbo with 4 motors and we have no problem.

thanks, we’ll try the suggestions

How much does it weigh? Normally, weight is a good indication of what ratio to use.

Our bot is about 17 pounds and we have a 4 motor turbo drive woth 3.25in wheels and have no stalling problems. We have all of our drive motors plugged into a power expander. We used all brand new bearing flats, motors, and metal on our base as well. There is no way to make an old bearing flat anything like a brand new one. The new metal also helps ensure its straight to reduce fricton. Lastly new motors are just better than old motors considering they’re brushed motors. We have slew rate code and use jpearmens smart motor library. We can go from match, do two skills runs, and go to another match without trouble using these techniques.

We have a six wheel tank drive with the back two wheels on each side powered and chained together

What would be the benefits of having 6 wheels and chaining the back 2 wheels together?

@spartanshl The six wheels allow the weight of the bot to be spread out more. Having the back two chained makes sure that the drive doesn’t loose power if the robot tips, that way it can still drive.

I’m running 3.25 on high speed with a external ratio of 5/3 on four Motors. The 5/3 actually makes it faster than 3.25 Turbo and I haven’t had any stalling issues. We have no Sluw control. My robot weighs 19.5lbs I have no idea why it doesn’t stall. However I run all of my drive motors from the cortex.

Been running 4 motor 4" turbo for 5 weeks now haven’t burnt out once unless i am being aggressive with it,
runes for around an hour until it stars to slow down and i have to change the battery. Check for friction, chaining wheels together can create a lot of friction…

Kids run 4 turbo motors on an x-drive with 3.25" wheels, haven’t stalled.

If you want your drive to have more torque, then just add rubber bands!

+1 to this

we did, and we just changed to 3.25 in high speeds now just to be safe