Unlike PV inverters, EV on-board chargers usually don't have efficiency specifications published by manufacturers. Studies done on charger efficiency are limited in the number of vehicles that can be tested. I decided to test the charging efficiency of a Canadian 2023 model Kia Sportage PHEV.
I performed the test with the Kyungshin EVSE that was provided with the vehicle, set to 12 amps. The EVSE was plugged into a 240V outlet via a 18m, 10 AWG extension cord. The L14-30R outlet is wired to the electrical panel with 6/3 aluminum cable. Measurements were made at the electrical panel using a Peacefair PZEM-016, logged with a python program I wrote. I initially took measurements with a clamp-style meter, but the readings were too variable, and could not account for power factor.
Considering the connectors and wire resistance, I estimate the losses between the electrical panel and the EVSE to be about 1%. For a typical home level 2 30-amp charger installation, the losses would be much higher, likely over 2%.
The Sportage PHEV battery capacity is 13.8 kWh. To charge from 20% to 100%, the PZEM-016 recorded 12.55 kWh of energy. The energy stored in the battery was 80% of 13.8, or 11.04 kWh. The efficiency is therefore 11.04/12.55 = 0.8797, or about 88%.
