On recent +700 mi trips from Huntsville AL to Coffeyville KS and later Huntsville to Richardson TX (aka., Dallas,) I got a lot of cross country charging experience and began to wonder about charging strategies. For example, which makes more sense:
This is what my earliest SuperCharger session looked like:
So I blew up the tier 2 session to get:
The initial charging is slow, probably to measure the battery state. Then it reaches a peak of 101 kW. I then digitized the profile to make this table:
Domestic charge rates in Huntsville are $0.11/kWh so the peak charging rate on the road is just 50% higher and quite affordable. So here are the actual SuperCharger costs on the Huntsville to Richardson and back trip:
First segment should be from a non-SuperCharger source, a hotel/motel or RV park, where a full charge can be put on the car. This avoids the 80% SuperCharger range limit.
Always leave with a 30 mi reserve range to the next SuperCharger but have handy the PlugShare map of RV parks, J1772, and distribution chargers along the route. If the reserve range reaches 10 mi, divert to these alternate charging sources.
If using an RV park, make sure you have a set of 30A plugs and/or adapters. There are different styles.
Bob Wilson
- $0.26/min - tier 2 above 60 kw, short and fast for shortest range
- $0.13/min - tier 1 below 60 kw, long and slower for maximum range
This is what my earliest SuperCharger session looked like:
So I blew up the tier 2 session to get:
The initial charging is slow, probably to measure the battery state. Then it reaches a peak of 101 kW. I then digitized the profile to make this table:
Code:
min kW kWh total kWh $/kWh Total $
1 65 1.08 1.08 $0.24 $0.26
2 73 1.22 2.30 $0.21 $0.52
3 80 1.33 3.63 $0.20 $0.78
4 90 1.50 5.13 $0.17 $1.04
5 97 1.62 6.75 $0.16 $1.30
6 101 1.68 8.43 $0.15 $1.56
6 101 1.68 10.12 $0.15 $1.82
7 101 1.68 11.80 $0.15 $2.08
8 101 1.68 13.48 $0.15 $2.34
9 101 1.68 15.17 $0.15 $2.60
10 101 1.68 16.85 $0.15 $2.86
11 101 1.68 18.53 $0.15 $3.12
12 101 1.68 20.22 $0.15 $3.38
13 101 1.68 21.90 $0.15 $3.64
14 94 1.57 23.47 $0.17 $3.90
15 75 1.25 24.72 $0.21 $4.16
16 54 0.90 25.62 $0.29 $4.42
Code:
date time Tier 2 Tier 1 mi (PS) location
05/18 15:30 0 0 0 Huntsville AL
05/18 19:30 16 50 206 Memphis TN (1)
05/19 01:12 16 23 163 Little Rock AR
05/19 04:30 14 20 133 Texarkana TX
05/19 06:50 6 19 98 Sulphur Springs TX (2)
05/19 10:00 81 LaQuinta
05/19 17:22 12 99 Plano TX (3)
05/21 13:13 4 16 101 Lindale TX
05/21 16:00 0 0 103 Shreveport LA (4)
05/21 17:59 6 34 104 Monroe LA
05/22 00:38 12 17 Pearl MS (5)
05/22 09:36 12 7 118 Pearl MS
05/22 11:41 13 11 91 Meridian MS
05/22 18:16 16 8 144 Birmingham AL (6)
05/22 20:50 106 Huntsville AL
- Huntsville-to-Memphis exceeds the 80% range, 192 mi. This suggests the longest segments should start with a non-SuperCharger charge session using a distribution, J1772, or NEMA 14-50 EVSE overnight.
- Sulphur Springs was more of a biology break to get out of reserve range management. The rest of the trip was normal car behavior.
- The distribution and J1772 ESVEs at the hotel/motel were powered off and this was Sunday. We weren't sure we'd get them turned on Monday so I drove downtown to use the Plano SuperCharger. Sunday afternoon it was very busy and I picked up a quick charge but by 7PM it was all but empty and there were restaurants calling my name. Open question, if you use the phone app to stop charging before reaching the car, do you still get idle or other tier 1 charges?
- Shreveport never charged for our session ... Thanks TESLA.
- We stopped at Vicksburg and put the portable kennel up on a nearby RV park but we didn't have the right electrical plug for 30A service. Using 12A, 120VAC it was obvious we were losing charge and it wasn't clear we'd have enough to reach Perl MS the next morning. So I took a midnight trip to Perl to put on a strong charge, 144 mi battery range at the RV park and left the kennel in operation. I visited the casino and left with an extra $79 and took at nap in the room. With unusual speed, my wife got ready quickly to see her dogs and we were on the road by 8AM.
- We didn't realize how bad the I-20 backup would be so we took a detour and in the heat, AC was necessary. Then about 20 miles beyond the construction, another backup as a truck had rolled off the road and a fire truck was blocking lanes. Autopilot worked great and someone in a tall work truck rolled down their window to ask if I was driving without using my hands . . . he was impressed. We barely found the Birmingham SuperChargers which due to construction was accessible by only one road. The battery was so low we initially lost AC. Once we had enough to reach home, we were off. I used the map to take short-cuts in Birmingham and Huntsville.
First segment should be from a non-SuperCharger source, a hotel/motel or RV park, where a full charge can be put on the car. This avoids the 80% SuperCharger range limit.
Always leave with a 30 mi reserve range to the next SuperCharger but have handy the PlugShare map of RV parks, J1772, and distribution chargers along the route. If the reserve range reaches 10 mi, divert to these alternate charging sources.
If using an RV park, make sure you have a set of 30A plugs and/or adapters. There are different styles.
Bob Wilson