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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.

Paul Gipe

 

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Nice data and well presented. My wife and I were in Snowshoe, WV (~3500' MSL) having charged to full at the Tesla destination charger with my Tesla Tap. We had 210 miles showing on the GoM. Of course, SS is on the top of the mountain and the last 7 miles to the resort is UP-hill. So the GoM thought we might still be driving as we had for the last 5 miles. We had 200 miles to our destination in Huntington, WV (~500' MSL). We arrived at home with 120 miles still available. This is mostly because it is net DOWN-hill all the way home. But, I am sure, the GoM underestimated the range because of the nature of the driving UP to the lodge two nights before. Thank goodness for regenerative braking and recapturing that gravity-induced potential energy.
 

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Great trip report, Paul!

Running 10% below ABRP's usage estimates is about right for my experiences as well. I have a feeling that quite a few Bolt EVs have gone where no other EVs have gone before up to this point. I know I've taken mine a few places it probably shouldn't have gone....

Yes. I would not go on a long trip with Eric unless wearing Depends!
Me neither. >_>
 

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Great write-up and read. It helps those of us who are hesitant to take road trips in our Bolts but don’t because of (perhaps unreasonable) anxiety about the trip.

Thanks for posting!
 

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I have a feeling that quite a few Bolt EVs have gone where no other EVs have gone before up to this point. I know I've taken mine a few places it probably shouldn't have gone....

Me neither. >_>
Having said that, I am amazed at how accurate the GoM mileage is. I once, near home, drove until no numbers were showing, but I have never "run out of electrons"!
 

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Having said that, I am amazed at how accurate the GoM mileage is. I once, near home, drove until no numbers were showing, but I have never "run out of electrons"!
I think my biggest problem with the Range Estimator at this point is how inaccurate it is for the first 3/4 of the battery. Yes, even I get range anxiety looking at it. The only reason I soldier on is because I've completed the same leg many times before and know what the Bolt EV is actually capable of. In my experience, the Bolt EV's Range Estimator doesn't start getting accurate until you hit 25-30% battery.
 

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The only reason I soldier on is because I've completed the same leg many times before and know what the Bolt EV is actually capable of.
I don't wait until I get further into my journeys to adjust driving methods. I calculate a "buffer" and achieve it asap. I once even starting out to Columbus, OH, in the winter, with 178 miles showing and 184 miles to go. I drove more slowly (50 mph in a 55 mph zone) until my "buffer" was 24 miles. Then I sped up to 55 and watched the buffer. It stayed steady. Then I got into a 65 mph zone. I sped up to 60 mph and calculated my buffer every 15 minutes. I eventually got to about 62 mph with a steady buffer that maintained until I got to my destination DCFC at Easton Gateway. That method usually keeps range anxiety to a bare minimum.
Keep up the good station ratings! Even though far away, it is nice to see your reasoning explained.
 

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I don't wait until I get further into my journeys to adjust driving methods. I calculate a "buffer" and achieve it asap. I once even starting out to Columbus, OH, in the winter, with 178 miles showing and 184 miles to go. I drove more slowly (50 mph in a 55 mph zone) until my "buffer" was 24 miles. Then I sped up to 55 and watched the buffer. It stayed steady. Then I got into a 65 mph zone. I sped up to 60 mph and calculated my buffer every 15 minutes. I eventually got to about 62 mph with a steady buffer that maintained until I got to my destination DCFC at Easton Gateway. That method usually keeps range anxiety to a bare minimum.
Keep up the good station ratings! Even though far away, it is nice to see your reasoning explained.
I have used this method often, and it definitely works. The GOM is very good. I watch google maps mileage to my destination and keep the GOM middle number at or just above it by adjusting the CC setting, and watch Torque Pro for SOC remaining, for better resolution than the green bars. Using this method, I feel secure rolling into my stop on "low." The anxiety comes not from the car, but from the chargers...will they actually work?
 

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I don't wait until I get further into my journeys to adjust driving methods. I calculate a "buffer" and achieve it asap. I once even starting out to Columbus, OH, in the winter, with 178 miles showing and 184 miles to go. I drove more slowly (50 mph in a 55 mph zone) until my "buffer" was 24 miles. Then I sped up to 55 and watched the buffer. It stayed steady. Then I got into a 65 mph zone. I sped up to 60 mph and calculated my buffer every 15 minutes. I eventually got to about 62 mph with a steady buffer that maintained until I got to my destination DCFC at Easton Gateway. That method usually keeps range anxiety to a bare minimum.
Keep up the good station ratings! Even though far away, it is nice to see your reasoning explained.
Thanks!

I'm also observing your work with WV charging infrastructure. Good job. I feel like many of us owners are screaming at brick walls, so I hope those with the funds to build networks actually listen.

I might suggest to the WV folk to look at Francis Solar. Another Bolt EV owner recently drove through Oklahoma, and had a chance to use some of their chargers. The geography and dispersal of the Francis Solar regional charging network might be something that the State of West Virginia could replicate.

 
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