PlugShare has trip planning

PlugShare.com has a trip planning tool to map routes, identify chargers and estimate trip time. Teslas already have a trip planning tool so this is for Leaf, BMW i3, and other EV owners. I will use my BMW i3-REx as an example for a pure EV trip from Huntsville to Nashville.

1. Change the PlugShare car from BMW i3-REx to a BMW i3 for the default 72 EV mile range.
2. Calculate the kWh/mi by dividing usable battery kWh, 18.6, by range, 72 miles, or .258 kWh/mile.
3. If you have a fast DC charger port, measure the charge rate and convert to charge mi/hr. So the BMW i3 maximum rate, 40 kW, is 155 mi/hr.
4. Create a table of charged miles per hour for 208V at 16, 24, and 30 A, the maximum for the 7.2 kW BMW i3 charger:
   
   
   16 A is 12.9 mi/hr
   24 A is 19.3 mi/hr
   30 A is 24.2 mi/hr​

Start PlugShare.com on a monitor with at least 1200 pixels wide and set the filter for the fast DC charger, CCS. Having a NEMA 14-50 EVSE, I also include it (See Fig 1.) Scroll down and hit “Create new” under “Trip Planner.”


Entering my destination charger at the “Brentwood YMCA,” it drew an “Avoid Highways” route with a circle showing the EV range. The fast DC charger in Manchester TN disappeared from the range circle because the option “Show Along Route Only” meant Manchester was not close enough to display (See Fig 2.)


After disabling “Show Along Route Only,” the range circle included both the NEMA 14-50 at the Tennessean Truck Stop along I-65 and the fast DC charger in Manchester (See Fig 3.)


Clicking on the Manchester charger pop-ups the option to “Add to Trip” (See Fig 4.)


Enabling this charger draws the route to Brentwood but shows a red box warning “76.2 mi” on the Huntsville to Manchester segment. It is just over the rated 72 mi (See Fig 5.)

On a nice day without A/C or heating, driving the speed limit while using “ECO PRO” or “ECO PRO+” mode, the BMW i3 has just enough EV range to reach Manchester. Of course my BMW i3-REx has a gas engine in case the charge runs out. Fast DC charging in Manchester takes 40 minutes and costs ~$12 to get enough to reach Nashville.

“Total Distance: 138 mi About 3 hours 16 mins” of driving. “Total Time Including Waiting: About 3 hours 46 mins” trip duration, Huntsville to Nashville.​

So I replaced the Manchester charger with the NEMA 14-50 at the Tennessean Truck Stop and allowed Highway routing by disabling “Avoid Highways” (See Fig. 6.)

The slower, NEMA 14-50 charge time, ~2 hours, cost $3. However, the shorter distance means more reserve range for each segment to deal with heating, A/C, or bad weather.

“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.​

Always check the charger user log before leaving as they can beak. Worse, many “J1772” chargers do not document reduced charging rates. For example UAH limits charging to 16 A and Blink is well known to limit charging to 24 A. When initially charging, check to see if the rate matches your expectation by noting the SOC, taking a 5-10 minute break, measuring the time, and the increased SOC. Be a friend and include this in your charging comment.

Bob Wilson

 

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:


CONCLUSIONS

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 ~$14-15. It takes ~$6 gasoline to drive the same distance. However, on the return trip, the truck stop, ShorePower $2-$3 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