[rraudi owner]

The E-Tron Owners Manual suggests charging the battery to 80% for normal use and only charge to 100% when the range is needed. I also understand that the e-Tron is programmed to not give access to the full battery—only 80%. Is that the same 80% and charging to 100% is already protected by the limited access?

 

[bradhinkle]

You can charge to "100%"

Yes you can charge to what shows as 100%. Because that 100% charge is still limited by the eTron's programming to an actual charge of only 85% of the battery capacity.

 

[ex-expats]

We have taken to charging ours to the 80% mark when at home, but leave it to charge to 100% when it is at our freebie office charger. While the car internally manages the battery pack to only utilize 83.5% or so of the actual 95kWh capacity Audi and other car manufacturers basically tell you to avoid total top ups if you don't really need them as it will reduce overall wear on the batteries. Since we don't really need the range most of the time, we leave it around 80% or so. Depending on how you drive the car and where you can charge should dictate your charging routine.

Likewise, leaving it plugged in for long periods of time (like a month) is probably not a great idea. We accidentally did that to a BMW PHEV and found the capacity had been reduced significantly on its small capacity.

I am hoping that Audi can programmatically improve efficiency of this model over time (as Tesla did with the original Roadster) since the range is the biggest downside on this car.

 

[ioannisk]

80% protects the top, 83.6 kWh protects the bottom

The e-tron has a 95 kWh battery. But only 83.6 kWh (88% of 95 kWh) is available to the driver. I believe (but I'm not sure, if anyone has evidence to the contrary please provide it) that the remaining 11.4 kWh protect the bottom of the battery, so it never goes fully empty. So the 80% recommendation is to protect the top (so that the battery does not get fully charged). Lithium-ion batteries do NOT like being fully charged, which is why your iPhone battery loses about 15% of its capacity every year: because you use it all the time and you charge it full at least once a day. I set my charging target to 80% except when going on longer trips (more than 70 miles away), or when encountering a free charger (yes, there are still some available); in those cases I charge to 100%.

 

[Sammk]

Very interesting points by both @bradhinkle & @ioannisk. But basically both are saying the opposite of each other. I’m still confused. should you charge you battery to 100% (which is let’s say approx 80%-88% in reality as Audi doesn’t let you use your full battery) or should one charge at 80% ( which in reality will be 80% of useable battery by Audi) ?

 

[polyphonic]

Audi reserves 12% of the pack total: 8% on the bottom, 4% from the top.

So when the screen shows “100%” that’s actually 96%, and when it shows “0%” that’s actually 8%.

There is an internal document floating around that confirms this.

 

[Sammk]

80% protects the top, 83.6 kWh protects the bottom

The e-tron has a 95 kWh battery. But only 83.6 kWh (88% of 95 kWh) is available to the driver. I believe (but I'm not sure, if anyone has evidence to the contrary please provide it) that the remaining 11.4 kWh protect the bottom of the battery, so it never goes fully empty. So the 80% recommendation is to protect the top (so that the battery does not get fully charged). Lithium-ion batteries do NOT like being fully charged, which is why your iPhone battery loses about 15% of its capacity every year: because you use it all the time and you charge it full at least once a day. I set my charging target to 80% except when going on longer trips (more than 70 miles away), or when encountering a free charger (yes, there are still some available); in those cases I charge to 100%.

interesting. What is your charging practice? Do you believe in more Shallow micro charges or less frequent charges where u let the battery fall to 20-25% and then recharge?