EV charging is a very peculiar process: on the one hand, it is rather simple, but on the other hand, it requires knowing certain intricacies. For example, imagine the following situation: you arrive at the 120 kW charging station, plug the connector into your EV, start charging and...the whole time the car is charging, the power does not exceed 90 kW. Sometimes it can be even less - barely reaching 80 or 70 kW. Why so? Let us just say - this is normal! And now let us explain the reasons for that.

The first reason is the limited charging capacity of the EV. It would seem that EV manufacturers tend to increase the charging power for obvious reasons (the faster you charge, the less is the stopping time) - for example, Hyundai Ioniq 5 can hold a charge from 200 to 230 kW, аnd Porsche Taycan – up to 280 kW. However, even among modern EVs there are models with on-board charging with power of less than 100 Kw. For example, Citroen e-C4 – 101 kW; FIAT 500 New - 85 kW, Hyundai Kona Electric – 77 kW.

Unfortunately, not all EV owners know technical characteristics of their cars. Basically, when buying a car, they are guided by two criteria - brand and power reserve. But the EV owners learn more about the maximum charging power - either AC or DC - only when the charging process has already started. As a result, they can find themselves somehow disappointed.

The second reason is the distribution of charging power among several cars. For instance, you come to CCS Combo 2 charging point and get all 120 kW, but when the second EV owner with a CHAdeMo port arrives and connects to CHAdeMo, then 120 kW are divided between two EVs. However, our GO TO-U app offers a VIP Connector service, so that you can reserve all 120 kW for yourself - in this case, the power of the charging station will not be shared with another EV. 

The third reason is temperature control. Unfortunately, if you just connect your EV (with power capacity of 150-250 kW) to fast charging for, let's say, 120 kW, there is a chance that it will charge slowly (less than 100 kW). Even Tesla Model 3 will not be able to charge at high power if the battery is very hot, or, conversely, it is freezing outside.

The hot battery situation is clear - this is the way to prevent overheating. Basically, the maximum charging power means the short-term peak power, which the battery can take for a few minutes. Then, the controller restricts it in order to prevent overheating. That is, it would actually be great if the average charging power reached 100 kW when charging from 0 to 100%. Usually, the maximum charging power is generated at the start or closer to the middle of the charging process, and at the end it decreases.

At the same time, if the car has active fluid cooling, during the first 10-15 minutes the car will be charged with limited power to cool the battery, but later it can get more power. But air-cooled EVs will probably not reach high power due to high probability of overheating.

As for the cold, it is also about "temperature stress" for the battery. If the car was left in the cold and the battery, respectively, is cold, then when connected to charging, the system will not give a full charge. First, the EV will get about 30 kW from a powerful charger – just to warm up. Only then - as the battery gradually warms up - it will get higher power.

To sum up, we can conclude that charging power depends on the EV itself, the appropriate charger, the battery (besides, the charging power can also depend on the battery wear), as well as some external factors (environment). This is why the EV may not get the maximum charging power.

The EV owner/driver should take all these points into account. Knowing the EV charging speed will allow him/her to accurately plan the route especially when taking a trip. Our GO TO-U app allows you to look through the map of charging stations and reserve a charger at the necessary location for a specific time. You can also choose a charger of certain power.

May 24, 2022
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