I know that 15% is the number most use for charge loss. But I am wondering how it is calculated. Maybe the 1 kW charging rate registered on the HSI screen is inaccurate. The p4460 Kill A Watt meter I just got shows a charge rate of 1370 watts (1.37kW). 1kW / 1.37 kW = 73%. So this says a charge loss of .37 kW is 27%. Am I missing something here? Is there more to the calculation? Last night it took 3.17 kwh to get to a full charge (from zero EV miles I believe).
Charge loss defined as invested charge minus received charge divided by invested charge. Note, we are speaking of energy (charge) not instant power (kW). Note also that power is not constant during the charging process. The big unknown is the received charge (in kWh) car does not report this, but estimate range instead. If you assume your battery full usable capacity is 2.73 kWh (62% of the 4.4 total) than 3.17 kWh invested gives 14% loss.
As for the 1 kW charge rate the car reports, it is certainly inaccurate, in fact, I suspect it is not even a measured value but a constant in the software: 1 kW for 100-120V charging, 1.9 kW for 200-240V.
2.836 kWh was what ChargePoint reported for my full charge yesterday. Loss tends to be less when recharging at a faster speed. Unfortunately, the power source itself fluctuates too. Go around plugging your L1 charger into a variety of locations. You'll see that not 110-volt connections are the same. L2 can vary too. It makes a mess out of the calculations. I've just been using 3.0 kWh for my recording keeping and logging by SOC values (battery-capacity % remaining).
I didn't come up with the 15% charge loss but I assumed someone with a kill-a-watt measured the incoming electricity. With an OBD2 scanner you can track percent state of charge at empty and full. Then, do the math with 4.4 kWh capacity battery. Voila, they came up with an average 15% delta. Turn off signatures in Tapatalk Tapatalk
