What is the best way to preservere my e-tron battery

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Question: What is the best way to preserve my e-tron battery

Answer

Batteries degrades over time and there are many factors that increase degredation.

• High Speed Charging
• High Temprature
• High State of charge over long time.

Audi has a buffer on top so if you charge to 100% the real SOC is between 96 - 99% depending on version. Audi choose to reduce the top buffer on e-tron 55 on models produced after week 48 in 2019.

So even e-tron has a relativly large buffer, charging to 100% is not good for the battery. Audi recomends not to charge more than 80% on daily basis. This is shown in the MMI and in the user manual.

The user manual on charging level

The diagram below show hows battery degrade based on charging habits.

Based on this the optimal is probably to keep it between 30 and 70%, but how much better it is compared to just charge to 100% is impossible to know.

The buffer is limitations on the max and minimum voltage each cell can have. Having a 4% buffer on top means the voltage on each cell is limited to max 96% of the max voltage.

References

Durability Aspects of Fast Charging, Mechanical Constraint, and Inhomogeneity in Lithium-Ion Batteries
How to Prolong Lithium-based Batterie
Nissan Leaf battery degradation data: 24 vs 30 kWh batteries

Extending Battery Lifetime by Avoiding High SOC