Charging Limits

[aollivierre]

I can’t get my S to charge 100 percent. It stops at 98 percent. And if I tried to charge to 90 percent it stops at 85-88 percent. Is this normal for a 2014? I have 92k miles on the car.

And this charging at home or anywhere.

Service center says it’s nirmal and my batter is ok. I don’t feel it’s ok but then again I am still a rookie.

 

[murphyS90D]

The charge percentage, or miles, is an estimate. There is no way to measure the current charge level in the battery. They keep track of flow into the battery and flow out of the battery. Over time the calculation becomes less accurate. It is believed that draining the battery down to 5% (or lower but you risk running out) and then charging to 100% will increase the accuracy of the calculation. Some say this has to be done several times in a row. It is not easy to do because ideally the discharge should be done in one drive.

Does it really matter what the numbers are if the car goes where you want it to go?

 

[Pentium2004]

The charge percentage, or miles, is an estimate. There is no way to measure the current charge level in the battery. They keep track of flow into the battery and flow out of the battery. Over time the calculation becomes less accurate. It is believed that draining the battery down to 5% (or lower but you risk running out) and then charging to 100% will increase the accuracy of the calculation. Some say this has to be done several times in a row. It is not easy to do because ideally the discharge should be done in one drive.

Does it really matter what the numbers are if the car goes where you want it to go?

Would it not matter if the fuel gauge in your gas car didn't read correctly?

 

[BrettS]

From what I have seen on here, it is normal for a 100% charge to stop at a little less than 100%. I’ve charged my 2015 S60 to 100% a few times for long trips and it has stopped as low as 97%. Only once did it actually read 100%

However, I think it is definitely unusual for a 90% charge to stop at something other than 90%. I have never seen that happen in the year that I’ve had my car. But that said, the way the car handles the battery after the charge completes while it’s plugged in is different than most people expect. If you have it set to charge to 90% then once the car reaches 90% it stops charging. It won’t maintain the battery at exactly 90%, but it will allow it to drop as the car uses power to maintain its systems. Once the battery drops 4% from where it is set (86% in this case) then it will turn in the charger again and bring it back to to 90, then the cycle repeats for as long as it’s still plugged in. This is better for the battery than constantly trickle charging it to maintain a certain level.

So if what you’re saying is that if the car is set to charge to 90% and has been plugged in overnight or even for a day or two and you get in the car and see that it’s at 88% then that is totally normal. It likely charged to 90%, then allowed it to drop a little between the time it hit 90% and when you got in to drive. Depending on how long it has been plugged in it might have even gone between 86% and 90% several times and you just happened to catch it at 88%

On the other hand, if you have it set to 90% and you are watching it charge and it only gets to 88% and then stops then I don’t believe that is normal.

 

[aollivierre]

The charge percentage, or miles, is an estimate. There is no way to measure the current charge level in the battery. They keep track of flow into the battery and flow out of the battery. Over time the calculation becomes less accurate. It is believed that draining the battery down to 5% (or lower but you risk running out) and then charging to 100% will increase the accuracy of the calculation. Some say this has to be done several times in a row. It is not easy to do because ideally the discharge should be done in one drive.

Does it really matter what the numbers are if the car goes where you want it to go?

Guess not really. Just want to make sure my battery integrity is where it should be and that Tesla is not attempting to get out of handling the issue at hand. If there is an issue.

 

[aollivierre]

Would it not matter if the fuel gauge in your gas car didn't read correctly?

Yes. Don’t want to ever get into a position when you run out of gas or fuel because you depended on the number or gas at hand.

 

[aollivierre]

From what I have seen on here, it is normal for a 100% charge to stop at a little less than 100%. I’ve charged my 2015 S60 to 100% a few times for long trips and it has stopped as low as 97%. Only once did it actually read 100%

However, I think it is definitely unusual for a 90% charge to stop at something other than 90%. I have never seen that happen in the year that I’ve had my car. But that said, the way the car handles the battery after the charge completes while it’s plugged in is different than most people expect. If you have it set to charge to 90% then once the car reaches 90% it stops charging. It won’t maintain the battery at exactly 90%, but it will allow it to drop as the car uses power to maintain its systems. Once the battery drops 4% from where it is set (86% in this case) then it will turn in the charger again and bring it back to to 90, then the cycle repeats for as long as it’s still plugged in. This is better for the battery than constantly trickle charging it to maintain a certain level.

So if what you’re saying is that if the car is set to charge to 90% and has been plugged in overnight or even for a day or two and you get in the car and see that it’s at 88% then that is totally normal. It likely charged to 90%, then allowed it to drop a little between the time it hit 90% and when you got in to drive. Depending on how long it has been plugged in it might have even gone between 86% and 90% several times and you just happened to catch it at 88%

On the other hand, if you have it set to 90% and you are watching it charge and it only gets to 88% and then stops then I don’t believe that is normal.

Thank you for the input. Good stuff.