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Discussion Starter #1
I have been unable to drive the last 6 weeks due to surgery, so my wife has been switching between both our 2013 Volts throughout the day. She drives the one with the most charge evening out the miles between them. The AC is set exactly the same on each. I thought I would share an observation.

What I have noticed after 6 weeks is that the Battery Range Estimator when the battery is completely charged on each are significantly different. One the 2013 Volts almost always shows a range of 38 miles and the other almost always a range 43 miles.

This led me to think that one of the Volts was perhaps experiencing a degradation. However, I know that this is just an estimate. So I looked at actual miles traveled on a single charge. Both 2013 Volts travel about 39 miles on a charge with my wife driving.

Therefore with the same driver using both cars the actual miles driven is about the same. The Battery Range Estimator is significantly different. Just thought I would share how widely different these can be even with the same driver. Also, sharing so that I might shed some light and preempt the next person that might be thinking of starting another thread complaining about the Battery Range Estimator.

Remember, it is not the estimated range but the actual range that counts. P.S. I am still banned from driving, hopefully soon though.
 

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You’re omitted a crucial detail for the comparison, the kWh Used number for both cars at full battery discharge. If both Volts achieved ~39 miles AER, did they also both attain approximately the same kWh Used number (i.e., both were getting the same miles/kWh)? If so, the two cars may be using slightly different data in the range estimate algorithm. If not, perhaps other factors are coming into play (e.g., brand new tires on one car may require more power to go the same distance).
 

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I suspect one or both of two things. The guess-o-meter calibrates its "zero" when the battery is run down to the point the generator starts. The longer one goes from the last such event, the more its accuracy wanders. Also, use of "hold" confuses the guess-o-meter at least temporarily. So, IMO, the difference you're seeing is due to a different history of these events.

Best wishes for a quick recovery!
 

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I may be wrong here but maybe one of your 2013 Volts has the larger battery. I believe there was a switch somewhere where the battery went form 10 kwh usable to 10.5 usable capacity
 

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Seems to me the OP glossed over a number of details. My first impression was the wife was driving one fully charged 2013 Volt to full discharge and getting ~39 miles AER on one day, and the other 2013 fully charged Volt to full discharge on the next day and getting the same ~39 miles AER... as if both Volts were identically equipped, had the same battery, and the missing element was the kWh Used. If that number was about the same, then the speculation on the full charge range estimate difference could begin (ah, another "Tale of Two Volts ").

A closer reading shows the wife chose to drive "the one with the most charge" to even out the miles between the two cars. Thus we don’t even know if both cars were normally recharged overnight. The OP’s observation was that "both 2013 Volts travel about 39 miles on a charge," but was that a full-charge 39 miles in a single day (or single trip), or 39 miles over a number of days without overnight recharging? Perhaps a single day for one Volt, and multiple days without recharging for the other? Was one Volt used for a long work commute (freeway speeds, lower electric mileage, influencing the full charge estimate to be lower), and the other one was used later in the day (when it would be "the one with the most charge") for those short errands involving mostly slower around town speeds and higher electric mileage, especially if they were made just prior to recharging (i.e., influencing the full charge estimate to be higher)?
 

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Discussion Starter #7
Some additional information...

- Both Volts are fully charged overnight and even during the day. So she takes the one with a full charge.
- Driving conditions are essentially the same as the trips are for practices, doctor appts., errands and such. So the roads traveled on are the same.
- One car may not get fully depleted before she parks it and takes the other that has a full charge.
- Both Volts are identically equipped except for the safety features of backup camera and collision alert.
- Batteries are the same size.
- kWh used are usually between 10.2 and 10.5.
- The one that has 38 miles showing for the Battery Range Estimator has 50k miles on the odometer and the other has 31k miles.
 

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I may be wrong here but maybe one of your 2013 Volts has the larger battery. I believe there was a switch somewhere where the battery went form 10 kwh usable to 10.5 usable capacity
All 2013s shipped with the 10.5

Transition years were 2012 (10->10.5) and 2014 (10.5->17.1)
 
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