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I've owned my Volt for about 4 months now and when I first bought it would charge to 55 electric miles on 220v before I would get a "Charge Complete" notification from On-Star. Now, I get the notification that it's fully charges but, the console shows it at 52 mile. Is this cause for concern that perhaps the batter isnt holding the same capacity and is on the down slope already?
 

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I've owned my Volt for about 4 months now and when I first bought it would charge to 55 electric miles on 220v before I would get a "Charge Complete" notification from On-Star. Now, I get the notification that it's fully charges but, the console shows it at 52 mile. Is this cause for concern that perhaps the batter isnt holding the same capacity and is on the down slope already?
It will vary based on how you drive, higher speeds, climate control, etc will all drive that number down. It is like a range estimate in any car, estimates future driving based on past and current driving. Aka, guessometer
 

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Thanks! Looks like I need to relax on the hard acceleration and breaking a bit. :)

But, its just so damn fun!
 

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There is one other thing that affects the battery capacity. It's a full cycle of charge and discharge. If you keep utilizing only part of the capacity the battery tends to decrease the available charge. A few full cycles of discharge and charge will bring it back up to the full capacity.
 

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As others said it's a range estimate display, not a charge capacity display. History of your past drives reflect in the estimate.
 

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I've owned my Volt for about 4 months now and when I first bought it would charge to 55 electric miles on 220v before I would get a "Charge Complete" notification from On-Star. Now, I get the notification that it's fully charges but, the console shows it at 52 mile. Is this cause for concern that perhaps the batter isnt holding the same capacity and is on the down slope already?
It's an estimate and can really be ignored.
 

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You can probably relax. If it's a decrease it would be a first. We normally see a bunch of posts about battery concerns when the weather turns cold, but running the AC or any number of other things can make a difference.
 

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I've owned my Volt for about 4 months now and when I first bought it would charge to 55 electric miles on 220v before I would get a "Charge Complete" notification from OnStar. Now, I get the notification that it's fully charges but, the console shows it at 52 mile. Is this cause for concern that perhaps the batter isnt holding the same capacity and is on the down slope already?
this number is not your "charge capacity" but rather an estimate of your fulture electric range based on your past driving habits and the level of charge in the battery. This number will move all over the place. In the winter, when I blast my heater, I see the projected full charge range drop into the mid 20s, in the spring it gets into the upper 40s (this all in a generation 1 volt) and the cycle repeats year to year. no worries...
 

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There is one other thing that affects the battery capacity. It's a full cycle of charge and discharge. If you keep utilizing only part of the capacity the battery tends to decrease the available charge. A few full cycles of discharge and charge will bring it back up to the full capacity.
this is completely incorrect- these batteries do not have usage memory, which nickel cadmium batteries have, and which you are suggesting is the case here.
 

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this is completely incorrect- these batteries do not have usage memory, which nickel cadmium batteries have, and which you are suggesting is the case here.
It would also contradict the advice to keep the car plugged in, especially in extreme heat or cold, so the system can cool or heat the battery as needed. It's not too often that I use a full charge.

Best,
Rick
 

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this is completely incorrect- these batteries do not have usage memory, which nickel cadmium batteries have, and which you are suggesting is the case here.
The issue isn't that the batteries themselves have a usage memory, it's that the algorithms which estimate battery charge and range loose track of what a "full charge" level is over time unless you actually fully charge the battery. Therefore if you go for a long time without fully charging the battery the estimation algorithm starts to give poorer and poorer estimates, even though the battery itself is right as rain.
 

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The issue isn't that the batteries themselves have a usage memory, it's that the algorithms which estimate battery charge and range loose track of what a "full charge" level is over time unless you actually fully charge the battery. Therefore if you go for a long time without fully charging the battery the estimation algorithm starts to give poorer and poorer estimates, even though the battery itself is right as rain.
Mostly, I think it keeps track of how many miles per kwh you've been driving lately. How many kwh come out of the battery may change a LITTLE BIT with conditions (+/- 3-5% seems pretty normal), but the miles per kwh is a handy abstraction for climate control use, speed, technique, and typically-driven terrain, from one number we KNOW it has available, even if it's a calculated figure.
 

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The issue isn't that the batteries themselves have a usage memory, it's that the algorithms which estimate battery charge and range loose track of what a "full charge" level is over time unless you actually fully charge the battery. Therefore if you go for a long time without fully charging the battery the estimation algorithm starts to give poorer and poorer estimates, even though the battery itself is right as rain.
Tend to agree with this as I was having an issue with my 14 till I started to totally deplete the battery. After about 10 total depletes it started to show around 39 to 41 again. Later RJD
 

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The issue isn't that the batteries themselves have a usage memory, it's that the algorithms which estimate battery charge and range loose track of what a "full charge" level is over time unless you actually fully charge the battery. Therefore if you go for a long time without fully charging the battery the estimation algorithm starts to give poorer and poorer estimates, even though the battery itself is right as rain.
to get further into this, the chips that monitor individual cell performance monitor cell voltage and impedance very closely and they continually "learn" each cell, and yes, their understanding of each cell is improved by both the trickle charge used near the top of the state of charge window and by the deepest draw down of the battery allowed at the bottom of the state of charge window. If the top cell voltage allowed is 4.15 volts for example (just an example, I don't know what it is in the volt) the monitor chip learns as it goes how much energy comes in or goes out between 4.14 volts and 4.15 volts, if it has been a long time since the car went through that state of charge, then the chip's memory is old, not necessarially bad, but not upto date either....
 

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Discussion Starter #16
Thanks for all the replies. Very helpful and insightful. I was under the impression that it was a capacity meter and not an estimate. I took it easy on a few drives and the charge was back up to 57/58 for a few days.

I deplete and recharge the battery twice per day. Once to work (where I charge) and then back from work (where I charge over night).
 
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