HS motors max robot weight

Does anyone know the max weight of a robot that 4 HS motors on 4" wheels can handle efficiently without burning out all the time? I’m wondering because our current ITZ robot weighs 22 pounds and I’m skeptical that HS motors will be able to push it over the pipes with a mobile goal.

You’re running a risk with that. You can calculate a good estimate using torque, I don’t know how to do it though, but gl!

You could do:
Ideal Gear Ratio = ((393 Stall Torque)(# of Motors)) / ((Wheel Radius)(Max Weight of Robot))

If you build up a LOT of momentum, maybe. But it will likely stall.

So if the ideal gear ratio = 1, then I don’t have to gear it right?

Our v1 robot has the same weight (4" omnis) and would get over but not easily with a MG on full battery. You also have to keep in mind that you have to get back over and wont have any momentum. Also make sure you can extract yourself if you happen to get only 1 wheel over the bar. We will try HS motors again with v2 but trim some weight (especially in front/up top) and go to 6 motors. Good luck…

Depending on how you make the mogo lift you may not need to get the back wheel over at all

We replaced our base motors today and tried them. Surprisingly, they do work and can get the robot over the 1.13" pipe with a mobile goal. However, after a while (like about a minute of hard maneuvers and stress testing) they either slow down or stop working. I’m hoping that after we replace our entire bot with aluminum the problem will stop. Currently it is like 80% steel, so I’m hoping it will shave off a few pounds and put less stress on the motors.

I don’t know what you’re using on your robot, but if you’re using 5 x 25 hole plating for anything, there is usually a better way. Taking any plates off will get rid of a lot of weight. So will aluminum like you said. Also in most cases you don’t need a 5 wide c-channel for anything. So remove those unless they are absolutely neccessary.

I was referring to coming back out (though I see why you thought I meant back wheel), where you wont have much or any momentum.

Makes sense now.

I’ve heard that ~19 pounds is the max that a 4 motor HS drive can reliable carry, but I haven’t done any real testing to verify this.

It also depends on your wheel diameter. Teams usually go with 3.25" wheels.

Well this year, 4" wheels are better because they get over the bar easier

I would just calculate your optimum ratio for each and just figure out which has the fastest ground speed.

3.25" Aren’t bad at all for getting over the bar as long as nothing is lower than the c-channels on the drive

Yeah, they should clear it. You might even be able get 2.75ers to work.