Macbook pro battery problem

Hi everyone.

I'm having a problem with my mid-2012 MBP. The battery is showing as being in a "Normal" condition, yet it is also showing as either a negative or 0 mAh and between 10500 and 12000 mV

The mag cable is showing amber/orange on one side, and green on the other. The side the lights show up on doesn't change, regardless of how you plug the cable in. So if you turn the cable over, then the lights stay on the same side when plugged back in.

This is what the System Information App shows;

Charge Information:

Charge Remaining (mAh): 117

Fully Charged: No

Charging: No

Full Charge Capacity (mAh): 5178

Health Information:

Cycle Count: 82

Condition: Normal

Battery Installed: Yes

Amperage (mA): 0

Voltage (mV): 11045

Can anyone shed any light on this for me?