Should you charge an electric car to 100%?
You can charge an electric car in different ways. For example, via a regular home socket or (public) charging station or at a fast charger. It is always possible to charge an electric car to 100% at a public charging station, at home, or at a fast charger. With fast charging, it is wise to charge the EV (Electric Vehicle) at less than 100%. Car manufacturers often also state charging times of less than 100%. But why exactly?
AC or DC charging?
An electric car can be charged in different ways. This can be done by charging at a public charging station or standard charging station (all the same meaning), at a home charging station, at work, or at a public charging point. Charging in one of these ways is all via alternating current.
Alternating Current = AC which stands for Alternating Current. The electric car then converts the alternating current into direct current for the battery. This is a quieter way of charging usually up to 11 kW, occasionally up to 22 kW via a charging station at home or a public charging station. Via the home socket goes at a speed of 2.3 or 3.7 kW. The fact that it is faster at a charging station than via a socket has to do with the controlled way in which the power is supplied and that it is supplied to the EV via a good and safe cable.
If you want to charge your car even faster, you can supply your car with direct current, DC. DC stands for Direct Current. The car then does not have to convert the power from AC to DC via the inverter. The cables must be thicker to safely supply the power. The faster-charging speeds result in significantly shorter charging times, sometimes in less than 25 minutes. Charging your EV with direct current is called fast charging. The fast charging times are often specified by a factory in a 10 to 80% or a 20 to 80% charging time. This has a good reason.
Why you should not charge your electric car to 100%?
It makes no sense to charge the battery of an electric car to 100 percent because this is bad for its lifespan. In daily use, it is better to limit this to 80 percent, a limit that also saves you time during charging (the maximum charging speed is reached between 20 and 80 percent). Ditto when you park the car: avoid charging the battery to 100 percent. The onboard system makes it possible to determine the desired percentage. If you want to take a long journey, you can of course charge up to 100 percent. But that should be an exception.
After an electric car has been charged to less than 100% on a fast charger, fast charging is much slower. The reason for this is battery life. The chemical structure in the lithium-ion battery can eventually be subject to degradation. A large degradation has consequences for the range. To limit degradation as much as possible, you should let the battery cool down slowly because fast charging creates heat. That's why fast charging is a lot slower after 80%. The car manufacturer has set this up in software. As a result, it is of little use to fast charge longer than 80%. You should see a fast charger as a tool to get to your next charging destination.
Does this also apply to charging at a charging station?
Charging at a public charging station or at home is also slightly slower in the end. But that's only at the last few percent and for the same reason, to save battery. Charging at a public charging station is also less harmful to the battery. The slower you charge, the better, but we understand that this is not always convenient in practice.
Fast charging is about speed. The faster you can charge, the faster you can continue driving. But use it if you need to because it won't benefit your battery's health. And if you fast charge, don't charge more than 80%. After 80% it doesn't go fast anymore.
Don't drive with less than 20 percent
The reverse also applies: driving a car with less than 20 percent charge increases the degradation of the battery pack. It is therefore better to apply the rule of 20 to 80 percent to improve the lifespan.
Also, note that a full discharge (dead battery) causes damage to the cells. Even with a battery at 0 percent, you can still drive for a few miles, but at some point, it's over. Then the battery is not yet fully discharged, because it always needs a minimum current level for vital functions. Therefore, there is a difference between the maximum capacity of a battery and its actual usable or useful capacity.
Wrapping Up
Batteries remain the Achilles' heel of electric cars. The battery is expensive to replace and its life depends on the charging method and percentage as well. It is therefore advisable to not charge your battery up to 100% and not drive when your car's battery is less than 20%.
