With DC charging, most of the losses are outside the car, in the charging equipment and site cabling. I wonder if Tesla superchargers report their input power. With a 100kW charge, I can imagine a total 7kW loss (7% from AC transformer to car HV battery). That might include almost 1% loss in the car, say 900W for computers, pumps, fans, etc and 100W loss in the DC-DC converter. Though even 6% loss for high power charging equipment seems high.
But surely by law, as a rapid chsrge vendor you would have to charge (money per kWh) based on what you supply, not on the energy you use to supply that energy.
@powerfulx, you're in Australia and it's summer here, were you perhaps running air conditioning during these charges? If so, that could account for about half the 7kW discrepancy.
But I think it's more likely that the car is somehow misreporting the power into the HV battery.
Yeh dc is no loss, relay open in go juice.
Not quite zero loss. There will be a slight loss in the car's HV wiring, the CCS contacts, across the contactors, and some of the charge power will flow through the DC-DC converter to support the 12V loads. Also as I mentioned HVAC loads.
