E-Auto immer brav auf 80% Laden? Warum ich diesen QUATSCH nie wieder mache!

Summary

The video argues that routinely limiting an electric car to 80% charge is not automatically the best way to preserve its battery. The right charging habits and battery size depend on how much and how often the car is driven, its battery chemistry, and how long it spends parked.

How batteries age

The presenters distinguish two forms of battery degradation:

• Cyclic aging results from charging and discharging. Repeated cycling creates mechanical stress in cell materials, while high charge levels mean higher cell voltage. Guest Tom Bötticher recommends avoiding routine full discharges and charges and generally using a moderate charge range.
• Calendar aging happens over time, even when a battery is not being used. Chemical layers form at the anode, reducing capacity and increasing resistance. High temperatures and high charge levels accelerate this process.

In the video’s comparison, a phone battery cycles much more often than an electric-car battery. As a result, cyclic aging is more prominent for the phone, while calendar aging accounts for a substantial share of EV battery degradation. In some modeled EV cases, the presenters say, time-related aging contributes roughly two-thirds of capacity loss.

Driving profiles and battery size

Using a battery-aging simulator, the team modeled 13 driving profiles and assumed an 18-year vehicle life. Their goal was to see whether the battery’s useful life roughly matches the car’s—not to maximize battery longevity regardless of how long the car itself lasts.

Examples from the models include:

• Daycare driver: A small car with a small battery, charged frequently and typically to 80%, uses its battery relatively intensively. The model estimates about 0.8 battery-lifetimes over 18 years, close to the target.
• “Battery saver”: A driver who charges only to 60% and avoids fast charging gets a modeled battery life of about 37 years. Since the assumed car life is 18 years, much of that battery capacity may go unused.
• Seldom-driven second car: Low mileage combined with leaving the battery highly charged is particularly unfavorable for calendar aging, especially in hot conditions.
• Taxi: A high-mileage taxi with an LFP battery reaches the end of its modeled battery life after about 17 years, close to the assumed vehicle life. With an NMC battery on the same route, the model estimates 2.6 battery-lifetimes, illustrating how chemistry can change the result.
• Large-battery examples: A 100 kWh commuter who regularly uses the battery makes effective use of it in the model. A similarly equipped driver who rarely drives uses less than half of a battery-lifetime over the assumed period.

The takeaway is not to always choose the smallest battery. Instead, battery capacity should suit ordinary driving needs: a large pack can make sense for frequent long-distance travel, while someone who rarely drives may not need extra capacity for a few trips each year.

Battery chemistry and technological progress

The video compares LFP batteries with NMC and NCA batteries. LFP has lower energy density but is described as cheaper, robust, and long-lasting. NMC and NCA offer more capacity per kilogram and longer range, but may have shorter cycle life in demanding use.

A model comparison of a 2013 Tesla Model S and a 2020 Model 3, using the same NCA chemistry and a 15-year driving profile, showed both retaining more than the commonly cited 75–80% state-of-health threshold. The Model 3 performed somewhat worse in the model, attributed mainly to its smaller battery needing more cycles for the same driving. A modeled LFP comparison retained close to 90% state of health after 15 years.

These results are estimates, not precise predictions. The simulator draws on Tesla Logger driving data and published measurements of cell aging, but the presenters emphasize that it is an approximation.

Practical conclusions

• Choose battery capacity for typical use, not only for rare, exceptional journeys.
• Battery preservation matters most for high-mileage drivers whose packs may wear out before the car. LFP may be particularly relevant for such use.
• For parked cars, avoiding prolonged high charge levels and heat can help limit calendar aging. Parking at a lower state of charge is one practical way to do this.
• For very low-mileage drivers, extreme battery-saving habits may make little difference to whether the battery outlasts the car. A more useful question may be whether a smaller battery would meet their needs.
• Waiting for a “miracle battery” is most relevant to very heavy users who could benefit from improved cycle life or lower cost. For many ordinary drivers, the video argues, current batteries are already adequate.

Main speakers and sources

• Andreas Schmitz: Host and presenter from Akkudoktor.
• Tom Bötticher: Guest explaining cyclic and calendar aging.
• Analysis sources: Akkudoktor’s battery-aging simulator, Tesla Logger driving data, and published scientific measurements of cell aging.