Hello Tom

Just as I thought, the battery pack you are using does not have the current demand capability to drive motor loads (or other high current loads) continuously. Try a larger cell battery pack. Hint: The cell size A, B, C, D etc will give a rough idea of the current demand capability the pack can deliver. Generally speaking, the larger the cell, the more current demand it can deliver.

All may not be lost for your AA battery pack though, it may take a charge and used for low power electronics like a transistor radio, receiver or transmitter for instance.

Cheers
Eric Scott