Arrive empty, leave at 80% measured here
The pack takes charge hardest when it is nearly flat. Rolling into a Supercharger on 1% pulled 221 kW. By 46% it had settled to 81 kW, and by 80% it was down to 55 kW.
Energy · 39 sessions
What would happen if your EV had no charger at home?
Most comparisons price an EV at a wall outlet at home. This record has none: 39 stops in 47 days, and what each one took in time, in money and in planning.
A typical stop at a fast charger
- At the houseNo plug.Every kWh is bought away from home.
- On the road8 places6 Superchargers, 2 borrowed plugs
- At the charger21 minutesabout 33 kWh a stop
The places
8 places, one stop at a time.
No single plug at home to fall back on, so the car went where the chargers were. The busiest took 51% of every kilowatt-hour.
- Brentwood604 kWh 19 stops
- Nashville427 kWh 12 stops
- Florence45 kWh 2 stops
- Athens33 kWh 1 stop
- A private plug Lebanon28 kWh 2 stops
- Birmingham28 kWh 1 stop
- Smyrna22 kWh 1 stop
- A private plug5 kWh 1 stop
- 39stops
- 1,192kWh added
- 47days
The stop
Fast when it is empty. Slow as it fills.
The pack takes charge hardest at the start. By 80% it was taking 27% of what it took near 20%, so the same ten points cost 2.6 times the minutes.
Minutes to add the next ten points
- 20 to 30%2.7 min
- 30 to 40%3.4 min
- 40 to 50%3.9 min
- 50 to 60%4.8 min
- 60 to 70%5.8 min
- 70 to 80%7.1 min
measured here Above 80% this record has one session, so the curve stops where the data does.
The price
About 2.5 times a home outlet.
Most comparisons price an EV at the wall at home. Without one, every kilowatt-hour is bought at a public charger.
- $164more a month than home power, at this car’s pace
- 7.5%of what is billed never reaches the pack
Home power is the owner’s own estimate, $110 a month, not a bill, over the 2,238 miles a month this car is driving, at 293 Wh a mile. What was paid is every charging invoice, per kWh billed.
The week
About 2.4 hours a week at the plug.
An office week is fifty. Each block here is an hour; the lit ones are the time this car spent plugged in, the borrowed plug’s long sessions included.
- 21minutes at a fast charger
- 5.8stops a week
- $74a week, in electricity
Odometer 23,560.5 mi
Per mile 12.2¢
Degradation 0%
On FSD (Supervised) 95.1%
As of October 11.
The playbook
What to do about it.
Half of these come out of this car's own telemetry rather than a forum. Where a claim is measured here, it says so.
The last 20% costs you a whole session measured here
At Florence, 32% to 79% took 22.3 minutes and added 33.7 kWh. The very next session, 79% to 95%, took 19.9 minutes and added 11.6 kWh. Nearly the same time on the clock for a third of the energy. Unless the next leg genuinely needs it, stopping at 80% and driving on is faster.
Price varies more than you expect measured here
Across the chargers this car used the rate ran 25 cents a kWh to 59 cents, a 2.4 times spread, sometimes between two chargers a few miles apart. Checking the rate in the app before committing is worth real money on a full session.
You pay for more energy than you keep measured here
7.47% of what gets billed never reaches the pack. Budget for the billed rate, not the dash figure.
Stall count is a queue risk, not a speed rating practice
A 500 kW site with 8 stalls can cost more waiting than a 325 kW site with 24. The cheapest and fastest site per stall is also the easiest to arrive at behind three other cars.
Precondition on the way in practice
Navigating to the Supercharger in the car rather than on your phone warms the pack before arrival, which protects the early high-power part of the curve. It is the single free thing that makes a session shorter.
Plan the stop around the taper, not the meal practice
A 20 minute session is a walk and a restroom. A 40 minute session is sit-down food. Match the stop to the charge you actually need, and the trip stops feeling like waiting.
Heat is a tax at both ends measured here
The Birmingham to Athens leg ran 307 Wh a mile against 256 on the way down, in 105 degree heat with the climate system working. Summer road trips need a wider margin than the range estimate suggests.
Blended rate, all energy
41.7¢/kWh
$497.48 for 1,192.3 kWh. Supercharging alone runs 42.9¢, because 33 kWh came from a private plug that costs nothing to use.
39
Sessions
1,192kWh
Energy added
$497
Total spend
16.3hr
Plugged in
Energy added by day
10/10
Miles152.0 mi
Drives24
On FSD (Supervised)98%
Efficiency95%
Idle loss9.5 mi
Charged44.1 kWh, $20.42
measured. kWh that reached the pack, on the day each session started. The biggest day is September 4, 102 kWh, on the road trip to Birmingham. A day with no column had no charging.
Spend per day
09/04
Miles350.1 mi
Drives9
On FSD (Supervised)98%
Efficiency92%
Idle loss4.6 mi
Charged102.0 kWh, $40.58
measured. Flat days are days it did not need charging, or days it charged on the free plug. 19 of 47 days cost nothing at all.
Where it plugs in
Every city through October 10
| City | Type | Sessions | kWh | Peak kW | Billed a kWh |
|---|---|---|---|---|---|
| Brentwood | Supercharger | 19 | 603.8 | 240 | 26¢ to 59¢ |
| Nashville | Supercharger | 12 | 426.9 | 247 | 25¢ to 42¢ |
| Florence | Supercharger | 2 | 45.3 | 164 | 32¢ |
| Athens | Supercharger | 1 | 33.2 | 145 | 36¢ |
| Private charger, Lebanon | Level 2, no cost to us | 2 | 28.0 | 10 | free |
| Birmingham | Supercharger | 1 | 28.0 | 128 | 42¢ |
| Smyrna | Supercharger | 1 | 21.6 | 173 | 34¢ |
| A private charger | Level 2, no cost to us | 1 | 5.4 | 11 | free |
measured.
What happens next
Want to follow the next project?
Everything here started as a what-if and ended as a record. The crew hears the day the next one opens.