Vex Motor Limit

I know the brain has 21 ports but how many motors.

Im assuming you mean V5. 8 motors without pneumatics and 6 motors with pneumatics.


For vexU it is unlimited.

If you are not using it in competition, use can use all of the ports for motors, although the V5 radio uses one of the ports, so 20 motors. If you are competing in VRC, then CVC011 is correct, 8 V5 motors without pneumatics or 6 V5 motors with pneumatics.

I have not tried this for myself but if the Y-Split wires still work for the V5 ports then you could have as many motors as you can think of, but only 20 outputs, you could have 40 motors in pairs technically, but at that point you just start worrying about how long the battery will last. During the year at some point I’m going to make a chart reflecting motor quantity verses power consumption which will help out those in VEXU, but for VRC I don’t believe you will have much problems with battery consumption.

The Y-split wires will NOT work for the V5 ports. They may work for the 8 legacy ports on the side of the V5 Brain, however they are at 5 volts not the 7.2 volts that they currently run on. The V5 ports are completely different from the old ports.

Thanks for that clarification, I haven’t looked at the V5 brain yet so I was only making assumptions. I guess that whole plan about charts was pointless haha.

Technically, you could have 20 V5 motors and 8 393 motors, but that is not VRC-legal.

Or if you y-cabled each of the 8 legacy ports, you could run 20 V5 motors and 16 393 (or heaven forbid, 269) motors. Not sure why one would want to do that, but you could I suppose.

couldn’t you double y-split motors (put a y-split on a y-split) if you were a crazy person? or would the voltage be to low at that point to even turn the motors with no load.

I suppose that you could, but, yes, I think you run the danger of having a LARGE number of motors that just do not work do to voltage loss.

No, that is expressly forbidden in the Game Manual.

do u know why

You could theoretically do way more than this outside of competition. For example, you could split a single smart port into 8 3-wire ports. Now you have 8 393s running off a single smart port. I don’t know how many of these motors you could really handle running at once, but you could have way over a hundred 393s along with piles of sensors.

But there are strict competitions limits outside of VexU with the V5 brain: no 393s at all, and either 8 motors and no pneumatics or 6 motors and pneumatics.

There are only 5V for each 3-wire port though, so you can’t really run much from them. Im not 100% sure that you can even control 393s through a V5 brain. The 3 wire ports are meant for old sensors which dont need much power

Sounds like a challenge. Who can drain a fully charged battery the fastest?

So is using the 393s along with V5. The whole thing is a “what if”!

You can control the 393s through the 3-wire ports, but you are correct they will only be run at 5 volts. Not much good for competition (where you can’t use the 393s with V5 anyway), but helpful in PLTW and other classroom situations where the students are learning control structures and the actual performance of the motor is meaningless.

Great thanks for the clarification