I recently got an Excal 2 from a friend that was having issues with the battery connection. Upon receiving the unit he had taken the connection apart and was just bare wires. I cut back the brown wire that was broken and resoldered both connections to the copper posts. Now I am unsure of the polarity for the connections. I can see the wire colors through the clear battery compartment as red and black and I assume that black would go with the blue wire from the module but am unsure. Any help is greatly appreciated. Thanks