First, the goal: Tesla's claims that properly set up home-charging stations can get about a 91-percent efficiency rate.
Rob M. from Teslarati has been diligently tracking electricity used by his home charging station – made up of a NEMA 14-50 outlet that was professionally installed and Tesla's Universal Mobile Connector (UMC) – since June, as we reported here. The results for the month that ended July 21 revealed that the Model S was taking in about 82 percent of the electricity it was pulling from the system, indicating an 18-percent loss of electricity. Most EVs are thought to charge at an 88 to 90-percent efficiency rate.
The downside to his results? About $26 more per month in electricity costs than previously estimated on about 2,400 miles worth of driving. There is a positive upshot, though: his monthly fuel savings totaled about $334 compared to driving an internal combustion engine vehicle.
These early results are intriguing, and make us wonder... Is anyone else checking in on their Model S charging efficiency?