California’s first greater-than-50 kilowatt DC charger supporting CCS and CHAdeMO is now online and available for public use. How many kWh and miles of driving range can it add to the battery of an existing EV? We plugged in a 2017 Chevrolet Bolt EV to find the answer.
While the Bolt EV can charge at up to 55 kW, European tests have shown that the Kia Soul EV and Hyundai Ioniq EV can charge at up to about 70 kW with their smaller battery packs which are optimized more for power than energy density.
Other cars on the road today likely charge about the same on this new generation of charging hardware as they do on existing 50 kW chargers. Within the next year or so, new models including the 2019 Nissan LEAF, the Jaguar I-PACE, and the Audi e-tron will reportedly charge at a peak power of 100 kW or more.
The Bolt received about 26 kWh during the first 30 minutes of charging which represents over 90 miles of added range based on the car’s EPA ratings, which is consistent with the estimates mentioned in the car’s owner manual. A typical 50 kW (125A) charger would have provided a bit over 22 kWh of energy so this new charger was about 20 percent faster.
Even though the ChargePoint’s display showed the Bolt’s battery state of charge went from 12 to 97 percent, that does not reflect the actual final battery state of charge reported by the car itself.
The Bolt EV had it’s Hill Top Reserve mode enabled which prematurely ends charging in order to allow for full regenerative braking capability. Some owners also enable it to optimize long-term battery health. The car reported it’s final state of charge as 88 percent via Chevrolet’s smartphone OnStar-based app. This discrepancy of 9 percentage points (97 versus 88 percent), representing a bit over 5 kWh, likely reflects charging losses in the car while charging the battery pack.
The air conditioning system started after 19 minutes of charging to help chill the water-based coolant that circulates under the Bolt’s battery cells to keep them at an optimal temperature. Although the car that was charging was not fully instrumented with an OBD II reader, tests of other Bolts have shown that the air conditioning system can consume up to 4 kW of power during charging. Once the system appeared to activate it remained on until charging completed.
The charging power seen at this location is consistent with previous reports from high-power chargers in Europe with the Opel Ampera-e (a rebadged version of the Bolt) and at the several Electrify America 150+ kW charging locations open in the eastern USA.
The Express 250 charger, capable of up to 62.5 kW of DC output at up to 156A and 1,000V, is installed near the loading dock at ChargePoint’s headquarters in Campbell, California as shown on PlugShare.com.