I built my own KWH meter. I bought a used meter on eBay for $27.50, meter socket can from Home Depot for $25, cord and 6-20 plug and receptacle...total cost $65-70. I plug in my level 2 Duosida EVSE to the meter and the meter to the 220 line I installed in the garage so I can meter exactly how much power the Prime uses. I found a full recharge when only .8 mile of range was left uses 6 KWH's. See attached photo.
Hialah Meter Co (Hialeah Meter Company), which aims at the RV park / campground / marina industry, has a variety of re-manufactured mechanical and solid state meters, starting at $16.50. Bases start at $13.50, though unlike that base from Home Depot, I had to bore another hole for the second pigtail. But depending on which styles one chooses, this source may not be any cheaper than eBay. I bought mine several years ago, when prices were slightly lower. One meter (hardwired) is on the minisplit heat pump, a second (also hardwired) on the heat pump water heater, and a third (portable plug-in pig-tailed, very similar to OP's version above) for the clothes dryer. One meter was diverted to my rooftop solar PV system for a few weeks, from when it was first fired up, through electrical inspection, and until the utility could install their official production meter on my base (standard Home Depot item). When I finally get a plug-in vehicle, I'll sub-meter it too. Maybe a new meter, maybe repurposing the unit now on the dryer, which is there only temporarily to characterize our household use of that appliance. Though I'd like to keep monitoring for a few years after converting to a modern energy-efficient heat pump dryer. That upgrade is still merely a wishlist item, the market does not yet seem to be sufficiently mature for us to jump on that bandwagon.
Is that mean the actual electricity usage was 6 kwh for almost 0 range battery? What about charging loss? Some estimate up to 15% of charging loss.
I'm measuring about 7.2 kwh to charge from EV empty to full. As for charging loss... the car reads about 5 miles per kwh... my math based based on the actual power put in and miles driven is more like. 4.44 miles / kwh
I used P3 Kill A Watt meter to measure actual electricity usage to fully charge the battery from empty (EV 0 mile). The reading was 6.56kWh. I think this is actual kWh of electricity used. I used up all EV miles, and I had to drive additional 8 miles on HV to home before plugging in. The capacity of the battery maybe different depending on how much HV driving have depleted the battery charge before being plugged in, but the number seems to indicate there aren't too much charge loss if in fact the battery takes 6.6kWh to fully charge from zero EV state which is 75% of 8.8 kWh capacity.
