Poor power output on DRV8835 for arduino

Support Motor controllers/drivers and motors
1

Hi There,

I purchased the DRV8835 motor driver for arduino (Pololu item #: 2511).

I got this specific one becuase its the same as the Zumo robots runs and i was very happy with the performance of the Zumo. But this module seems to have seriously lower power output, which is made worse when i power both arduino and motors from the same battery.

First i tried to check if there was any known issues on the forums and found there was issues with these little tamiya motors, which is what i was initially testing on (some old RC car i was trying to hack)

then i tried one of the official HP 75:1 metal gear motors that came from one of my Zumo’s after i did a upgrade to 100:1. And the result was the same:

Very slow and very weak… with full gears assembled on the HP 75:1 micro metal gear motor i was able to stop the motors with little effort with my fingers… removing the VOUT-AVIN jumper to split the power made it marginally better but no where near enough power for something that can carry the weight of its self + a battery…

I am running the default example sketch on a UNO r3, with a 7.2Volt NI-MH battery pack at 700mAh — This was tests done where arduino and motors was powered

i also tested 9v to arduino + 4.8v/1300mAh to motor setup and same thing.

Can you pls let me know if i am doing anything wrong here with this setup. Also can you advise on best motors & power combo (for a simple robot type setup) for this driver.

TA

2

Hello.

I am sorry you are having trouble controlling your motors with your DRV8835 shield. Were you using the 7.2V battery as your motor and Arduino power supply? Can you post pictures that show how you have everything connected?

Also, after posting those pictures, can you remove your motors from the DRV8835 motor driver, and supply battery power directly to them to see if they run faster and have more torque? It would be good to use the 7.2V and 4.8V battery packs you are testing with.

When you say you are using the “default example sketch”, do you mean you are using the example demo code in our DRV8835 library? Are you running the sketch unmodified?

Was the blue shorting block on when you tested your setup with a 9V for Arduino power and a 4.8V battery for motor power?

What motor and power source work best for you will depend on the specifics of your robot’s application. If you tell me more about what it is you are trying to do after we troubleshoot your shield, I might be able to make some recommendations.

-Jon