100 or 90%: How much do you charge as a Tesla driver?

Have you ever wondered why the charging speed of electric cars is often given in "x minutes from 0 - 80%" and not "up to 100%"?

Charging a Tesla correctly

Different charging recommendations

Well, firstly, this naturally allows for significantly shorter charging times – but there's also a technical reason. Due to their chemical properties, batteries lose some of their capacity over time. Depending on how far and how intensely the battery is charged, this process can be accelerated or slowed down.

Maximum everyday charging capacity

But how far should you charge the battery at most? Tesla recommends only charging the battery to a certain limit during everyday use and only using its full capacity when you actually need it for a longer trip. The corresponding limit depends on the installed battery and is displayed individually in the charging menu on the touchscreen.

Generally, it's best to keep the battery below 80% in everyday use – only LFP (iron phosphate) batteries, which are mainly used in standard versions, should be charged to 100% every now and then to ensure proper calibration of the battery management system.

Tips for charging management

Adhering to these limits guarantees the longest possible lifespan and also reduces the average charging time: Due to the cell chemistry, the charging current drops rapidly above 80% charge level, meaning that the first 80% are reached relatively much faster than the remaining 20%.

By the way: Low battery levels are just as harmful as high ones. So avoid letting the battery level drop into the yellow zone. d.h...to allow the battery level to drop below 20%. If exceeding or falling below the recommended limits is necessary, it should be for a short time. This means: recharge as quickly as possible when below 20%, and drive briskly and "consume" energy when above 80%.

If the vehicle is parked for an extended period, a charge level between 20 and 80% should be maintained. It is helpful to know that a parked Tesla without any additional active accessories (z.B. refrigerators) loses approximately 1% battery charge per day.

Charging frequency vs. charging cycles

While the amount you charge the battery to is certainly relevant, contrary to popular belief, the frequency of charging is almost irrelevant. What matters for a battery is the number of charge cycles, which describes how many times it is fully charged from 0 to 100%. Someone who charges by 20% on five days doesn't "use up" five charge cycles, but only one. Accordingly, Tesla itself recommends charging the battery a little bit daily, rather than, say, once a week to 100%.

Charging speed and Battery types

What is relevant for battery lifespan, however, is how strongly and quickly the battery is charged. Fast charging stations, such as the Tesla Superchargers with charging capacities of several hundred kW, are excellent for saving time. However, they are rather detrimental to the battery, which prefers lower power levels, such as the 3 kW of a standard household outlet. Since this also has disadvantages (relatively high charging losses, safety issues, prolonged activity of the on-board computer during charging, and the battery not getting properly warm), charging at a wallbox with 11–16 kW is the ideal compromise.

Do you have experience with your Tesla's charging practices? Share your thoughts and tips in the comments below.