What you should know about fast recharging to make the most of its benefits

Fast  charging in direct current has made it possible to travel in an electric vehicle as long as there is  adequate infrastructure . To obtain the maximum potential of this technology, it is advisable to follow some basic tips that will allow you to take full advantage of it. Starting the charge with a warm battery, with the lowest possible battery capacity and knowing the vehicle's charge curve are the most important factors to consider.

Thanks to advances in technology,  batteries have managed to achieve sufficient autonomy to allow any movement, but they would not be very useful if it were not for the significant progress in recharging networks for electric vehicles,  which are expanding rapidly (and also very unevenly) by the different countries of the world.

Many of these chargers today only offer power of 50 kW , the maximum that electric cars on the market allowed for up to a year, which require 80 minutes to recover 400 kilometers of autonomy. However, most second-generation electric cars will admit powers of  100-125 kW , which will reduce the time needed to recover that autonomy by less than half. The technology already exists to achieve chargers with powers of up to 350 kW that will provide compatible electric vehicles with a range of  350 kilometers in 10 minutes .

Start charging with hot battery

When the battery is hot, the chemical processes are accelerated, which means that in this state, when connected to a charger, the electricity will flow faster and recharging will be accelerated. In fact, recharging a very cold battery can actually cause damage to it .

The recharging speed is automatically reduced when the battery temperature is too low, but also when it is too high. Some electric cars on the market have a battery preheating function . In the case of Tesla , it starts automatically when there is an established route in the browser and the car approaches a Supercharger. If you do not have this system, it is advisable to go to the fast recharging point after you have been driving for a couple of hours , so that, with complete certainty, the battery will be at a high temperature.

Charge when the battery is empty: the glass of water full

Charging a battery can be compared to filling a glass of water . At first, it is possible to fill it quickly, but as more liquid enters, the process slows down, until putting the last drops becomes a very slow process.

When the recharge starts with the battery level low, the power offered by the charger is the maximum it can give during a given period of time. As the battery fills up, the power is reduced and charging slows down. This effect is reflected in the charging curve of the electric car.

The charging curve of an electric car

Each vehicle and each battery has an ideal charging range. However, in most vehicles, reaching a 70 or 80 percent charge percentage, the power that can be supported is significantly reduced. When reaching 80%, the reduction is so important that on many occasions the remaining 20% ​​takes as long as the section already recharged. This is why many drivers prefer to charge only up to 80% each time. As a consequence they will stop more times to recharge, but the total recharge time will be less .

Manufacturers do not usually give the owner the complete load curve, but only some of its most significant inflection points. Most of them indicate the recharge time needed to reach 80% capacity . They also indicate the maximum recharging power that the battery can absorb: 50 kW, 100 kW, 150 kW. But that does not mean that the car recharges at that power during the entire process. Quite the contrary. The period in which peak power is maintained is generally quite short.

In addition, charge managers have rates that take into account different parameters: kWh charged, recharge minutes, or a combination of both . Therefore, it is important to know how the vehicle is going to behave during the process in order to estimate the cost and benefit of charging longer (cost per kWh) or charging faster (cost per minute).