A weekend with the Solterra

This wasn’t a very typical weekend, but it wasn’t exactly unusual, so I thought I’d write it up to give a glimpse into what a real world weekend was like with a relatively limited range Solterra. There were other options than the ones I chose (e.g., I could have swung by the office to charge, or found a DCFC station), but these pieces fit together neatly enough. This is with a 2024 Subaru Solterra Limited, and I don’t currently have the option of charging at home.

Friday I topped the car off at the office, charging to 100%, so, starting with a range of ~200 miles (temperature highs in the mid-60s, cooler at night, SoCal “winter”).

That night, took my houseguests to dinner. Total driving about 11 miles. Didn’t record the State of Charge (“SOC”) because it didn’t matter, but it was probably down maybe 5%. ~190 miles remaining.

Saturday morning we got up early and drove to Knott’s Berry Farm (where there are no chargers), probably doing 75+ mph to keep up with traffic. Call it 31 miles, at probably around 3.2 miles/kWh. Down another 15% (?), ~159 miles remaining.

After a few hours at Knott’s, had to take my guests up to LAX, another 30 miles, so another ~15%, to ~129 miles remaining. From LAX home would be ~6 miles, 123 remaining, and Sunday I had to drive out to Chino Airport for a minute, a ~99 mile round trip, which would have me parked at home, if everything went perfectly, with about ~12% left on the car. But it was midday, I had a reservation for Disneyland I’d forgotten to cancel (and Disney has a “no-show policy”), and I kinda wanted to see the holiday lights & decorations one last time for the season, and I could charge at Disneyland, so ... Yeah. 37 miles to Disneyland’s Toy Story parking lot, where I was almost certain to find an open Level 2 charger. I should arrive with 92 miles of range left.

Disneyland was busy but I was able to find an open charging station (actually two, but the first one had two non-working plugs so I had to get back in the car and drive a bit further to find an open spot with a working plug). Luck was with me, as the car next to my spot, sharing the charger, was done charging, so my Solterra would get the full 6.6 kW capability of the ChargePoint station.

Solterra charging at the Toy Story Parking Lot

I hooked up at 16:57 and headed into the parks. I was at 47% SOC with an estimated range of 91 miles at that point. ChargePoint reported I was getting 6.2 kWh from their charger; my back of napkin math says about 85% of that ultimately made it into the Solterra.

When I had time to crunch the numbers, I came up with: 38 miles home from Disneyland, a 99 mile loop on Sunday to Chino Airport with a traditional stop at Applebee’s on the way home, and if I wanted to have 10% left the next morning (a comfortable buffer), tack on another 21 miles, so I’d need an estimated range of 158 miles. 

Elapsed  ChargePoint kWh   ChargePoint miles est.  Solterra miles est. SOC
1 hour   6.0259            +21                     +16 (107-91)        55%
2.25     13.6638           +49                    
3.0                                                +51 (142-91)        73%
4.0      24.8801           +90                     +69 (160-91)        82%
5.0                                                +81 (172-91)        88%
5.4      32.9587                                   +91 (182-91)        93%

So, call it 33 kWh (at $.35/kWh, $11.54 in electricity) to “refuel” from 47% to 93%. Arrived home with 76% SOC and 149 miles remaining range, more than the minimum I’d planned for (used slightly less energy than I’d conservatively planned for, and had stayed in the parks later as, e.g., the single rider line for Incredicoaster was incredibly long!).

Long Single Rider line for Incredicoaster!

On my way out to Chino, I was running a little behind due to a traffic accident, so most of the trip I was pushing 80-85 mph (keeping up with traffic flow). I’d reset the Solterra’s energy estimator mid-trip and was seeing around 2.9 miles per kilowatt hour, lower than I’d planned for, but only about 10% off and I had a larger than planned buffer, so I wasn’t worried. After getting off the freeway and navigating higher speed surface streets for a few miles, my average was back to 3.2 m/kWh (what I usually see and plan for), and I arrived at the airport with 99 miles estimated range remaining, and a 50% SOC.

I arrived home from my airport / Applebee’s loop with 62 miles estimated range and a 31% SOC, after using adaptive cruise control to keep the car around 65 mph on the way back (sometimes a bit slower, with slower traffic in front of me), lurking mostly in the #3 / #4 lanes towards the right of the freeway. Reset my energy estimator before leaving Applebee’s and for the trip home (surface streets at the beginning and end, and about 45 miles of 65 mph freeway travel), averaged 4.2 m/kWh.

Monday morning, reset the energy estimator again to see what my (short!) commute looked like. In ECO mode with adaptive cruise control set and using the RES+ function to start from stop lights (which gets the car rolling gently before building up to speed somewhat slowly), averaged 4.1 m/kWh over the 2 mile commute. Arrived at the office with a 60 mile estimated range, still at a 31% SOC. The car estimates my 24A 240V Level 2 charger will bring the car up to full charge in 8 hours 30 minutes, for about 8%/hour of charge. (I conservatively use 7%/hour for planning purposes.)

Whatever charge I get should more than last me to my usual Friday recharge for the weekend.

Charging at the office after a relatively busy weekend

Update: 4.5 hours after plugging it in, it’s up to a 66% SOC (~7.8%/hour) with an estimated 131 mile range, and estimating 4 hours 10 minutes until fully charged. I forgot I have a board of directors meeting tonight in Torrance, but even with that excursion (a ~34 mile loop), I should have plenty of charge left for the week by the time I duck out in another hour or so (or even if I left right now, really).

I’m going to see if I can’t keep my per-trip efficiency above 4 m/kWh. I’d like to see my range get solidly back above the 200 mile point, psychologically.

Update 2: After 6 solid hours of charging, SOC 78% and an estimated 154 mile range. 2 hours 50 minutes estimated until fully charged.

Update 3: Left the office with 164 miles of estimated range and 83% SOC. Reset the average and ran some errands on the way to the board meeting, mix of surface streets and freeway (with some traffic snarls and one long relatively steep uphill surface street climb, where I saw the average efficiency drop into the 2.x range). Reset again after the board meeting for the drive home.

ODO  Miles M/kWh SOC Est. Range
3774 17    4.3   76% 151 (-13)
3792 18    3.9   69% 137 (-14)

I may have cracked the code... Of course, then yesterday I was knocked out with an awful (but apparently fast) flu, and stayed home today as well (Wednesday), so haven’t had much of an opportunity to see what the daily realities are. More soon.

How did I get to ~4 M/kWh? Keeping the speed between 65-70 mph on the freeway (anything slower is dangerous), and being slow off of stops (typically letting the cruise control “resume”). Driving not anything like the way I normally would.