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Old 01-01-2019, 06:36 PM   #2 (permalink)
Engineering first
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Join Date: Mar 2009
Location: Huntsville, AL
Posts: 813

14 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

17 Prime Plus - '17 Toyota Prius Prime Plus
90 day: 58.25 mpg (US)
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Now that we have a model from PlugShare, how does the theory validate with reality:
  • “Total Distance: 104 mi About 1 hours 50 mins” of driving. “Total Time Including Waiting: About 3 hours 50 mins” trip duration, Huntsville to Nashville.

Driving aggressively with cruise control set on the +5 to +10 mph of the 55 to 75 mph speed limit, I reached the Tennessean Truck Stop quickly, parked and plugged in:

To my surprise the NEMA 14-50 was energized. I used it to configure my EVSE for 32 A service and called the ShorePower number, (888)841-3137. The service clerk was nice and quickly setup my account. Apparently I get the first 10 hours free and they waived the $1 connect fee. My two hours would only cost $2 if I was being charged ... nice.

I walked the dogs, visited the bathroom, and had a coffee with hot truck stop soup. The EVSE was configured for a maximum of 32 A but the BMW i3-REx will only accept up to 31 A. Not knowing how the charging session was timed, I set an alarm to go off after 1 hr and 30 minutes:

This agreed nicely with the posted 30 A limit. Along with a $5 package of beef jerky to reward the dogs, it was time to drive home.

The drive back, I took a detour to work on a 2003 Prius with a bad brake booster. This added miles so I had to approach the free, Huntsville, fast DC charger driving efficiently to avoid the 6% threshold that would start the REx:

Even with the detour, I still reached the Huntsville, fast DC charger without burning gasoline:


The 111 miles with the detour exceeds the 104 miles in the PlugShare model even with the extra detour miles. It was ~50 F (10 C), dry, and low wind showing the drive to Nashville was entirely practical. Had I driven the speed limit on the first leg and used the full, 2 hour charging, I would have had extra kWh reserve and fewer miles to reach Huntsville.

Charging at an EVgo station in Nashville runs about $12 so total EV cost to Nashville would be ~$14. It takes ~$6 gasoline to drive the same distance. However, on the return trip, the truck stop, ShorePower $2 and free Huntsville charge would be a significant savings over the $6 in gasoline to drive back. By happy accident, this validation test costs nothing to drive 111 miles.

Bob Wilson
2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
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mort (01-01-2019), NeilBlanchard (01-01-2019), redpoint5 (01-08-2019)