Debunking the myths about BEVs

Battery Electric Vehicles (BEVs) have revolutionized the way we think about transportation, offering more sustainable alternative to traditional fuel cars. However, despite the growing presence of BEVs, several concerns about their practicality persist. Some of them were covered in the first three articles of this Debunking the myths miniseries already. The one we will talk about today is that BEVs driving range is too short and it takes too long to recharge them which makes them less convenient for a daily use. In this article, we will look into the realities behind these concerns, exploring the current state of BEV range and charging times, and what else to take into consideration with this in regard.

Whether or not the BEVs range is sufficient relies on the average driving needs of the driver. As per the US 2022 survey, the daily driving needs of an average US household range between 10 – 75 miles per day, meaning that cca 85% of households travel less than 100 miles on a normal day. As most BEV models offer more than 200 miles of range on a full charge, and almost all new models can cover over 100 miles per charge the driving range should not be an issue for an “average driver”. Moreover, car manufacturers are planning to introduce more long-range models in the near future so the range is expected to get higher. (1) On the other hand, some factors might negatively influence an EV’s driving range. Not only driving habits but also environmental conditions. For example, studies have shown that in cold weather, the range can drop by ~ 40%, especially due to the use of heating systems. (2)

As reported by IEA, “with increasing battery size and improvements in battery technology and vehicle design, the sales-weighted average range of battery electric cars grew by nearly 75% between 2015 and 2023, although trends vary by segment”.(3) In 2023, the average range for small cars remained around 150 km, slightly higher than in 2015, showing that this range is already adequate for urban driving. Larger, higher-end models, which already had above-average ranges in 2015, have seen little change through 2023, with their range holding steady at approximately 360-380 km.

How long does it take to charge an EV?

The straight answer is, that it depends. The length of charging is dependent on a list of variables and thus even the answer might vary. Some manufacturers claim, that a fast-charger will get your battery to 80% in 30 minutes. Based on CarAndDriver tests, it was observed,

“DC fast-charging times as low as 25 minutes from 10 to 90 % in a Porsche Taycan prototype, and as high as two hours in a GMC Hummer EV SUV, while the average sits just shy of an hour.” (4)

To start from the top, three key factors impact the charging time considerably, the battery size of the EV, the charger capacity of the car, and also the power source. (5)

Intuitively, the larger the battery the longer it might take to charge it, when we assume all other conditions are constant. However, the only constant in today’s world is the changing conditions and as we know, as the car batteries, charging station types, and other conditions vary, we also have to consider certain “deviations” from the theoretically assumed numbers. Think about charging in a similar way as you would think about filling up a bucket with tap water. The size of the bucket but also the flow of the “tap” defines how fast the bucket will be filled up. The “tap” is the bottleneck and the ability to get filled up faster vastly depends on its flow, in other words, the water pressure. Which in the electricity terms can be translated into voltage.

Following North American standards, the common residential 120V AC outlet, also called Level 1, can take days (40-50+ hours) to charge a fully depleted battery pack of the BEV to 80%. For the Plug-in-hybrid, it can take approximately 5-6 hours. (6) Level 2 charging stations charge at a higher- rate through 240V in residential or 208V in commercial applications. It is estimated it can charge the BEV battery in 4-10 hours, and the PHEV in about 1-2 hours. The typical power output ranges between 7-19kW. The fastest charging is ensured by the Level 3 fast charging stations which provide power output of 50kW – 350kW and estimated charging times of 20 minutes – 1hr for BEV. (7) For example, Tesla’s V3 Superchargers provide up to 250kW of charging power, meaning it can replenish 1000 miles of range per hour. (8)

When calculating the charging time of the BEV, the calculation formula: battery size (kWh) / charger power (kW) = charging time (hours), shall be taken more as an approximate estimate. When considering deviations and other factors influencing the real-time of charging the battery electric vehicle, it also depends what is the status of the battery when you reach the charging station. Batteries are often made in a way to optimize their life and also limit the risks of overcharging. That is why when there is less than 10% of battery or more than 80% the charging slows down when being fast-charged, exactly for this optimization reason.

Not only a battery level but also the compatibility of the charging station and the vehicle might add up to this deviation. The charging point does not always reach its promised peak, and not every model can charge at the maximum charging power, as they are limited to lower kWh. In other words, if the charging station has a higher output than the vehicle charging rate, it will always default to the vehicle charging rate limit. On the other hand, if the charging point output is lower than the vehicle charging rate, it will allow only as much as the output offers.

Weather conditions shall also not be underestimated. Cold weather might result in slower charging times, taking it longer to reach full capacity due to increased internal resistance. On the other hand, hot weather might help with faster charging, however, the temperature extremes will more likely lead to faster degradation of the battery. (9)

Before jumping to conclusions about the speed of BEV charging, it is better to narrow down what type and model of BEV the driver might be considering, the conditions and also the infrastructure available. With increased charging infrastructure and more fast chargers being deployed across EU, US as well as Asian countries, time constraints during charging are becoming less of an obstacle.