Answered: 7.2V Robot Battery NiMH 3000mAh Battery Issues

We have a total of 4 batteries. We ordered 2 over the past few months, and the other 2 we ordered back in the summer. 2 of the batteries cause our cortex to short out. We knew this was happening a few months back, but I did not remember to bring it to your attention.

We have fully charged each battery, then stick it on the robot. It turns on, but if we bump the battery, or the robot hits something a little to hard, the battery shorts out everything on the cortex causing our limited connection to fail. We think the connection on the batteries are shot. The other two batteries work fine.

Will we have to buy new battery’s (this is what I am assuming), or will you replace them?

These are the batteries:

We are also using the [Smart Charger w/Optional Power Cord to charge the batteries.

Thank you!](“”)


I would like to RMA your Cortex and battery just so I can duplicate the problem on my side.
Would this be possible?
When is your next competition?


What do you mean RMA?

What I have done to sort of fix it is make the 3 prongs in the battery wider. That holds the battery in better. I think the problem was the battery was not very tight when it was in the battery port.

Our next competition is on the 1st of Dec. at Wildstang Regional. Then 2 weeks later we have another competition. We have a large break after that.


RMA means you have to send it back for analysis.
Yes, modifying the connectors on the battery/Cortex usually alleviates this kind of problem.