Books
Wind
Feed Laws
Renewables
About

EV Articles by Paul Gipe

June 14, 2020
Paul Gipe

Chevy Bolt 225 Mile Roundtrip with 21 Percent Charge Remaining


We're a one-car family and our vehicle is a Chevy Bolt EV. So when friends decided to go backpacking in the Golden Trout Wilderness during the Covid-19 pandemic, social distancing required that we each drive separately to and from the trailhead.

In a conventional vehicle--a gasser--that can travel 300 to 400 miles on one tank of fuel that's seldom a problem. But the calculus is a bit different with an EV (Electric Vehicle) even one such as the Bolt with a relatively long range.

EPA's official range for our 2017 Bolt is 238 miles. That's more than enough for our typical use. This trip wasn't typical. It's more than 110 miles to Blackrock trailhead on the Kern Plateau and requires crossing a 9,000 foot (2,800 meter) Sherman pass 25 miles before you get to the trailhead at the end of the road.

There's one lonely level 2 station in Kernville midway from Bakersfield to the Blackrock trailhead that I could use if I needed it. I confirmed through PlugShare that the charger is open during the pandemic, though the Forest Service ranger station where it's located is closed.

Friends on the trip also have a Bolt. They wouldn't chance it and drove their Prius instead.

The EV route calculators I use before embarking on such a trip said I should make the roundtrip with a few kWh to spare. Both ABRP (A Better Routeplanner) and Chevy's Energy Assist app said I should arrive back home with 4 to 6 kWh remaining from a 60 kWh battery pack. For Eric "1%" Way that's more than enough, but for me that's cutting it pretty close especially on a route I haven't done before--and to my knowledge no one else in an EV has done as well.

But I was game. I've driven the Bolt 27,000 miles and know the limitations of the route planners. For example, they often overestimate consumption on long descents. This was to my favor. So I was confident the Bolt would make the trip without the need to stop in Kernville to charge, but until you drive such a route, it remains an unknown.

This time of year the weather is good if not hot before you hit the higher elevations. With shelter-in-place orders still in effect, traffic was light, and the Bolt was a pleasure to drive on the narrow, windy Forest Service Roads. For much of the route, I had the road to myself. Once I left Kernville, I seldom got above 45 mph.

View from Sherman Pass over the Kern Plateau into the Golden Trout Wilderness.

I arrived on schedule at the trailhead using 10% less charge than estimated by ABRP, my preferred route planner. That's what I wanted to see. I prefer arriving with a bit more charge than planned. I don't like surprises and using significantly more charge than planned can leave you stranded by the side of the road. And the Kern Plateau is not the Hwy 99 corridor that runs the north-south length of California's San Joaquin Valley with fast chargers ever 20 or 30 miles. There's very little traffic in the forest and the nearest tow truck is 60 miles away in Kernville. Worse, there's no cell-phone service and the Blackrock ranger station is now closed too.

California evening primrose (Oenothera californica) on the arkosic sands along Big Dry Meadow in the Golden Trout Wilderness.

After the hike out of the back country over Boggy's Pass it felt good to sit in the car again and whiz along the mountain road with the wind whistling through the window. It was exhilarating after trudging along for a few days with a 40 pound pack on my back.

I arrived at Sherman Pass using half the charge ABRP estimated. I was now a good 8 kWh ahead of my original plan. That was more than enough to get to Bakersfield with a comfortable margin. Then I started the long descent to Kernville, dropping 6,500 feet over 35 miles.

Typically an EV will gain one kWh for every 1,000 feet loss in elevation. That descent should have given me a good 6 to 7 kWh. Once you're down off the mountain there's a 20-mile section to Kernville that should have cost me about 5 kWh. The net would gain me 1 to 2 kWh over that segment and that's about what both estimators calculated I would get. However, my actual consumption was much less. I gained almost 4 kWh from Sherman Pass to Kernville.

My sense is that neither estimator takes into full account the Bolt's aggressive regenerative braking. I drive in "L" or Low all the time. I seldom had to use the brakes on the mountain road, relying instead on regenerative braking to slow me down. The estimators may assume that the vehicles are driven in "D" or Drive. I don't know. There's no option for selecting driving mode in either estimator.

By Kernville I was comfortable that I had more than enough charge there was no need to stop and charge briefly for the drive to Bakersfield.

The segment from Kernville to Bakersfield used about 10% more than estimated and I arrived with 21% charge remaining after 225 miles. I used 46.4 kWh for an overall efficiency of 4.9 miles/kWh.

The 21% State-of-Charge from Torque Pro after using 46.4 kWh suggests that our Bolt has 59 kWh of usable capacity after nearly three years of use.

I'll have a chance to check the consumption on all these segments again in a few weeks. I am heading into the backcountry on the Kern Plateau for another backpack.

And for those who follow my work, yes, there was an earthquake. It was only 5.5 magnitude, but there were at least three tremors that I felt. Of course it was nothing like last year. See Unearthly: The Little Lake Earthquakes in the Back Country.

 

 

 


© 10/2011-08/2020  -  all rights reserved by wind-works.org  -  paul gipe  -   webwork by www.beebox.com