Charging from 30% to 77% State of Charge 50 45
50 kW Charger 25 kW Charger
40
power (kW)
35 30
Both chargers at or below 25 kW
25 20
Less than 7 min additional charge time with 25 kW
15 10 5 0
0
5
10
15
time (minutes)
20
25
Based on internal data from Fuji Electric Corporation
Charging Time After all of the challenges and hurdles of DC Quick Charging are taken into consideration, one may wonder why they are not summarily dismissed and Level 2 chargers chosen instead. The answer? Charging time. The purpose of making quick chargers available for public use is to offer drivers a value-added solution that makes their life easier, thereby encouraging the adoption of EVs around the country. People are simply not willing or able to wait 4 hours for their cars to charge in the middle of their hectic days.
50 kW chargers provide a complete charge faster than a 25 kW charger can, but, contrary to popular belief, the charging time is not cut in half by doubling the power from 25 kW to 50 kW. This is the number one misconception among station owners, users, and even EV industry insiders. A 50 kW charger will charge at a faster rate for the first 7-10 minutes of the charging cycle, after which it drops off to the same rate as the 25 kW charger as directed by the vehicle’s Battery Management System (BMS). The BMS dictates charge rate based
on a number of factors including cell temperature, state of charge and cell balance. Therefore, the reduction in charging time is just 7-10 minutes. Ultimately, station owners will make the best decision for their business and their customers, and DC Quick Chargers should be a major part of that process. 25 kW Quick Chargers offer cost savings in terms of product, installation and operating costs over 50 kW charging products. The increase in charge time between 25 kW and 50 kW is not as significant in real-world scenarios as many people are led to believe.
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