GM "miles" in the Volt/Spark/Bolt are based on the car's recent experience and outside temperature, rather than just the amount of charge in the battery.
Before assuming the hardware is broken, I'd start with the operating environment. Are all the settings the same as the were. In particular, Comfort climate control mode and auto-defog can chew through a bunch of extra energy.
With 50k, you are presumably familiar with the drop in range in colder weather, and are driving the car the same way over the same roads as before?
A couple of Volts have had jammed rear brakes that led to lower mileage - use an infrared thermometer to check the temperature of each disc after a drive.
If you have a solid dataset of extended range gas mileage for the car, it might be worth taking an extended drive that you've done before in similar condition and seeing if the gas mileage lines up - one way to tell between a battery problem and a more general car problem.
Another would be to use an energy measurement outlet to charge the car and see how much power it takes to fill.
Before assuming the hardware is broken, I'd start with the operating environment. Are all the settings the same as the were. In particular, Comfort climate control mode and auto-defog can chew through a bunch of extra energy.
With 50k, you are presumably familiar with the drop in range in colder weather, and are driving the car the same way over the same roads as before?
A couple of Volts have had jammed rear brakes that led to lower mileage - use an infrared thermometer to check the temperature of each disc after a drive.
If you have a solid dataset of extended range gas mileage for the car, it might be worth taking an extended drive that you've done before in similar condition and seeing if the gas mileage lines up - one way to tell between a battery problem and a more general car problem.
Another would be to use an energy measurement outlet to charge the car and see how much power it takes to fill.
