Replace Brain Battery Message

I am getting a “Replace Brain Battery” message on a robot brain after I use the robot for a few minutes. I have used all different types of pieces to figure out the problem with no results. What can I do to fix this issue? Thanks.

Lorobotics,

I have seen this issue before on robots running on AA batteries, can you please a VEX Robot Battery Instead:

If you are already using a VEX Robot Battery please make sure that the battery is solid red when placed on the charger, not blinking red.
Allow it to charge for a few hours until it turns the charger LED turns green.

Then try to use it again.