Answered: Power expander

Today , during our training , we had a fierce robot right with other teams , when they tried to flip us , we lower our arm down however I still fell. When I checked the robot later , 4 wire were pulled out of our micro processor and when we attatched it back , it did not move . When we change the power expander , it eventually move . And our power expander was controlling the arm. 1 motor however spoilt . We also have loose battery. The black and red tips were able to come out . When my team mate pulled out the battery , a spark came flying to his finger , cause it to swell . It could have taken his life . It was the new 9.6v battery . His hand is currently still swollen

We’re sorry to hear your robot was damaged during competition. Do you have any specific question we can answer regarding your power expander?


Firstly , i would like to apologize for my bad English. This was not a competition. As i have said in the first post , this happened during our training. I would also like to clarify that it was a “fierce” fight instead of fierce robot. I would say that it was fierce as both robot were equally match . The battery was a 7.2V battery . (

And the question i would like to ask is " Would the power expander be damage, if wires were pulled out with force ."

Hi larhal,

I’m sorry to hear that you are having problems with your Power Expander.
I don’t think the Power Expander will be damaged if you pull out the motors while the safety clip is engaged. If anything was to damage it will be the connectors on the motors.

I would recommend you to test your Power Expander by using different motor ports on the Cortex and different motors on the Power Expander.
Also make sure the Power Expander shows the correct battery voltage.
If you have a fully charged battery, the Power Expander should blink green when the battery is connected.

Hope this helps.


That explains why our power expander was blinking. Thanks for the help !

another problem… our power expander was blinking green, but turned to red, after getting pushed by another robot during practice. it was blinking red slowly, not as fast as when it was blinking green. our voltage for both battery was approximately 7.9 and 8.0 respectively.


A slow blinking red LED on your Power Expander means the circuit breaker was tripped.

The circuit breaker will recover itself if you allow the motors to rest for a few seconds, so don’t push any buttons on the Joystick.
If the circuit breaker is recovered and your battery is fully charged you will see a fast blinking green LED on the Power Expander.

Power Expander.pdf (579 KB)

Eli Osornio , thank you for helping me solve so many problems . I really appreciate it