Charging time vs. battery life

The charging time is crucial for many people when buying a charger. Among other things, it depends on the charging power that your charging station provides. Generally speaking, the greater the vehicle’s and the charging station’s charging power, the faster the charging process. Consequently, a 22 kW charger can charge twice as fast as an 11 kW charger.

However, this is overridden by what is known as the “weakest link principle”, which determines the maximum charging power in a charging chain. If the electric car’s charging power is 11 kW, even a more powerful charger cannot speed up the charging process. Additionally, it must be considered how much charging power the main connection can provide.

Plug-in hybrids, for instance, often have a charging power of just 3.7 kW to 7.4 kW. But, in most cases, electric cars can be charged with 11 kW of power.
On the other hand, the time saved by a more powerful charger is tempting at first glance – but it’s not always the best option for the battery. This takes its toll on the cells, harming the battery life. While charging with less power is certainly more tedious, it’s far more gentle on the electric car’s battery. It would be best if you only charged quickly when necessary.

Additionally, it’s essential to avoid extreme battery states – such as complete charging or deep discharging. State of charge (SoC) levels between 20% and 80% are ideal. This is where innovative software, such as ChargePilot, our intelligent Charging and Energy Management, can be helpful. By controlling the charging processes, battery aging can be significantly reduced.

In practice, you must know for what time slot your electric company provides a discount (for example, a night-hour tariff) when the price per kW costs less. Then divide your EV kW capacity into a given number of hours to understand how many kW per hour you have to charge. For most of our clients, this number stays close to 6,8 kW. So unless you have a Tesla or the latest generation Audi or BMW EVs, having an 11kW charger will be the most reasonable purchase with even a 50% future-proof charging capacity guarantee.