I'm new to Pololu & I have a Zumo 32U4 design question

Has anyone considered & or tried changing the battery box (yes I realize that it also doubles as the chassis) for something that will house batteries with a higher power density rating (ie: li-ion) then using four 4 AA batteries? Also can the Zumo 32U4 handle any higher voltage then 6V, say 7.4V for instance?



Yes, in its default configuration the Zumo32U4 can handle battery voltages as high as 10V, though you can raise the maximum allowable voltage to the motor drivers’ limit of 11 V by disconnecting or modifying the battery voltage divider. We mention this under the “Power” section of the Zumo32U4 user’s guide, which you can find under the “Resources” tab of its product page.


Thanks Jonathan. How do you get the Arduino IDE to talk to the Zumo 32u4? I’ve found lots of instruction on how to get the A-Star 32u4 to communicate but nothing to get the Zumo 32u4 to connect & communicate. I even followed the instructions on how to connect the A-Star, of which that went fine. However I don’t have an A-Star, I have a Zumo 32u4 & it still wont connect. Can anyone help get this working?


Ok, please disregard the previous message. It was my mess up, however I have it working now. Sorry this newbie has a lot to learn yet.

Though I could use an answer to a different question that could lead to a cool project.

My Zumo 32u4, I got a set of the 100:1 HP dual shaft motors for it. Could the motor drivers handle a second set of motors? My idea; use the extended tracks & have 2 pairs of matching motors driving my one bot. I want to make my daughters bot a strong contender, however I obviously don’t want to kill my daughters new bot.

Thanks Dao

I am glad you figured out the answer to your other question; thanks for letting us know.

As for your most recent question, adding a second set of motors will not likely work with the Zumo32U4’s existing electronics. The board uses two DRV8838 motor drivers, which cannot handle the full stall current of two high-power micro metal gearmotors running at 6V. That setup could work when the Zumo is moving around without any load, but if the current drawn by the motors at any time exceeds what the DRV8838 drivers can handle, they will either break or shut down and change the performance of the Zumo. Additionally, there is a small amount of variance among motors (even if they are the same motor model) so there could be uneven tugging on the Zumo tread even when powered with the same motor voltage. This could make the Zumo’s movement worse.

In your initial post, you asked about increasing the voltage supplied to the motors. You might already know this, but doing so will increase the speed that the motors rotate as well as increase their ability to deliver torque. So, using a higher voltage power source than the default 4 AA batteries will give your daughter a competitive edge.

By the way, I edited my earlier response about raising the maximum allowable voltage on the Zumo. The maximum voltage is limited by the motor driver, not the regulator, and the voltage is 11V, not 11.8V. We also updated the Zumo32U4’s user’s guide to reflect this.


Thanks Jonathan. Is there any tests that I can try that I can determine if & how close my motors are matched? Also are there any adjustments that I can make to the motors to get them closer in sync with another motor?

Additionally, for the high current draw I was thinking of using two (one for each side) of the MC33926 motor driver from you guys to handle the high current draw of the two motors. But obviously only if I can get the motors to work together properly.


You could quantify some of this variance by measuring the speed the motors rotate at when they are supplied with the same voltage. Then, you could write software that commands each motor at a slightly different duty cycle in a way that corrects for any offset in speed you might find.

I do not see any problems using the MC33926 driver to control motors like that. Since it can deliver 3A continuous, and 5A peak, it should be able to handle stalling two high-power micro metal gearmotors per channel, even when they are supplied with 7.4V. So, in that setup, you could use two drivers (one for each side of your robot) to control two motors each. However, if you wanted to compensate for any differences in speed by adjusting the duty cycles like I mentioned above, you would need an individual driver for each motor to address its specific variance.


Ya having 2 more, no wait. I’d already have 4 motor controllers in my design anyways. The two built in & the two MC33926’s. I could just just leave the two stock motors connected the way that they’re designed to be & then buy the two MC33926’s to drive the additional two motors. Wholly mighty mouse BatMan, I think this might just work! What do you think?

& actually then, do you guys have a less powerful motor driver board that would be cheaper? 3A & 5A peak is really far more then I’m going to need to run just a single HP motor.


I just remembered that you said you wanted to use “the extended tracks”. Do you mean using a pair of these 30T tracks instead of the 22T tracks that come with the Zumo? I’m not sure if your modified Zumo will be used in a mini-sumo competition, but if that is the case, please keep in mind that the rules for that kind of competition require the mini-sumo to fit inside a 10cm by 10cm square.

We do have other motor drivers that can handle less current. (You can find our entire selection of brushed DC motor drivers inside our brushed DC motor driverscategory.) In particular, it looks like the MAX14870 Single Brushed DC Motor Driver Carrier works with a 2S LiPo, and can handle the current draw of our micro metal gearmotors when stalled at that battery voltage. There is a chance the over-current protection could kick in (especially with a fully charged 2S LiPo, which can be up to 8.4V) if stalled, but you will have to decide for yourself if that is worth risking or not.