I've been trying to calculate whether using Uber to get to and from a Tesla SCtr to the hotel is more cost effective vs paying for Chargepoint at the hotel, but I'm a little confused on the amount of kWh used between charges. If I charge to 100% and started at 60%, does this mean I used 34 kWh of the 85 kWh battery? If so, then why does the dash show Total Energy Used since last charge to be only 28.7 kWh?
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
kWh used
- Thread starter TTT
- Start date
I don't entirely trust that "Total Energy Used" figure, as I think it doesn't count power consumption while parked. But there are two effects that work in opposite directions: first, although the battery is nominally 85 kWh, the "visible" portion is less. How much less is a matter of debate, but at least 5% of the battery capacity is hidden. In round numbers, assume you have 80 kWh of charge to go from 0 to 100% SOC. Second is losses. Chargepoint charges you for power it sends to the car, and some of that power is lost in the process of storing it into the battery. Others will have hard data, but I think the charging losses are about 10%, e.g. you'll use ~90 kWh to put 80 kWh into the battery.
To my way of thinking, the convenience of simply charging at the hotel would outweigh any small cash savings of charging at the SCtr.
As Robert noted, "kWh used" doesn't count power consumption if the car isn't moving ("P" or "N") or during pre-conditioning, and I suspect the same is true when in D or R at 0 mph, because waiting at a red light with the heat running full blast doesn't generate a higher energy use curve than stopping for a few seconds. I would not rely upon the "kWh used" - I'd probably use % SOC as an indicator if you really want to do the calculation.
And as Robert says, include overhead of ~10%.
Similar threads
- Article
