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January 30, 2016
Paul Gipe

EV Trip Report: Bakersfield to Palm Springs


Last weekend we took a trip to Palm Springs to visit a relative. January is always a good time to visit Palm Springs. The weather’s perfect, the motel we stay at has a world class pool and all for only $100 per night. It also gives me a chance to check out any new wind turbines in the San Gorgonio Pass for my work. (See Ogin Installs Ducted Turbines in the San Gorgonio Pass.)

From Bakersfield to Palm Springs is about 250 miles, a five-hour trip in a conventional car with a short stop for lunch. Our normal route avoids the LA basin by taking us across the desert and in the back way via Yucca Valley.

However, we now drive a 2015 Nissan Leaf, a mass-market Electric Vehicle (EV) with a limited range that necessitates frequent stops to charge the car’s traction battery. Because of the car’s limited range we must plan our route carefully through convenient charge stations, preferably stations that allow a quick charge.

This was our first expedition since our fall trip to Grover Beach. (See Bakersfield to Paso Robles Raises Questions on Energy Estimates.) On that trip I was pushing the boundaries of my range anxiety. This trip pushed my range anxiety even further, especially on the outbound portion.

Quick Charging

Convenient intercity travel with today’s EVs requires a network of DC fast or quick chargers (DCFC or DCQC). Often you arrive with 20% to 30% state-of-charge (SOC) and within 20 minutes you raise the SOC of your traction battery to 80% or more. Typically quick chargers allow you to charge for 30 minutes. Charging etiquette dictates that you charge to 80% and move on, especially if there are cars waiting to charge. However, we were driving a new route, some of the legs were long, and there was significant change in elevation on some legs. You consume more energy than normal ascending a long grade. For peace of mind, we wanted to charge to more than 80% and often more than 90%. At none of the stations on this trip did we encounter anyone else waiting to use the charger.

California’s network of DCQC stations is only now being built out. Some regions have no quick chargers at all, such as the Tehachapi Pass. We mapped a route that took us through as many quick charge stations as possible. Thus, the location of the quick charge stations largely determined our route.

The Routes

Generally, we prefer crossing the desert to reach Palm Springs than driving through the LA basin. I planned a route through Tehachapi then on to the quick charger at Palmdale. From Palmdale we would take a long 55-mile leg across the Antelope Valley to the quick chargers at Victorville. From there we’d drive down the Cajon Pass into San Bernardino and on to the quick charger at Calimesa and then on into Palm Springs.

As explained later, we had a change of plans and returned via a route along the 210, the foothill freeway. From Calimesa we took a long 58-mile leg to a quick charger in Azusa. Then it was another long 51-mile leg to a DCQC station in Santa Clarita and then on to the Nissan dealer in Palmdale. From there we retraced our route to Bakersfield via Tehachapi.

Energy Estimates

We use EVTripPlanner, an online estimator, and a tabular estimator based on the work done by Tony Williams, an early PV pioneer in the Leaf, to calculate how much energy we’d need for each leg. Both produce an estimate of the energy required per route segment.  EVTripPlanner performs its calculations in the background so it’s hard to tell what its assumptions are. The tabulator is much simpler, using assumptions derived from Tony Williams’ experimentation.

I like to arrive at my destination with a reserve of 20%. This provides some headroom for the unexpected and with today’s mass-market EVs you need to expect the unexpected, such as a charge station being offline.

Outbound we arrived at Tehachapi’s Mountain Valley RV park with slightly less charge than planned: 18%. We’d done this route several times and the low reserve at arrival surprised us. Nevertheless, we always enjoy visiting Larry and Jane at the glider port and had breakfast at the Raven’s Nest.

We left Tehachapi with 79% SOC, crossed Oak Creek Pass and arrived at the Nissan dealer in Palmdale with a 21% charge. This was substantially less than I expected and since this was a new route I was driving very conservatively. We used 11% more charge than planned.

EVTripPlanner estimated we’d need 9.3 kWh for this leg, but we used 11.6 kWh. That’s more than a 2 kWh difference, an amount that could make the difference between reaching your destination and being towed. The tabular estimator provided a range from 11 to 12 kWh depending upon the speed driven.

In most cases the tabular estimator is conservative, so there’s a tendency to use EVTripPlanner. However, I’ve now driven several legs on intercity trips where EVTripPlanner substantially underestimated the amount of energy needed. I still use EVTripPlanner, but on an unfamiliar route, it’s best to plan conservatively and drive conservatively as well.

The Bridge was Out

Never leave home without a map, especially if you use a GPS.

We drive with a GPS mapping program loaded onto my BlackBerry smart phone. The maps are on the phone so the phone doesn’t need an internet connection to map a route. (We also have LeafSpy loaded onto the BlackBerry to monitor traction battery stats.)

The GPS program is most useful in finding the location of charge stations, so I load the addresses of the stations into the program before we leave the house.

We’ve learned in the past to not rely on the GPS alone. This trip reaffirmed that in spades. You should never leave home without a paper map. You should never depend on the GPS.

The 55-mile leg from Palmdale to Victorville was already a stretch for us. We’d never done it before. EVTripPlanner estimated that the leg would require 11.4 kWh. However, the tabular estimator suggested that from 14 to 15 kWh would be needed. With only 18.5 kWh in the traction battery when we left Palmdale, I didn’t feel we had a lot of margin if EVTripPlanner was wrong.

Tony Williams’ mantra is “plan the drive and drive the plan.” As a pilot, Williams probably also has a “Plan B” if the flight doesn’t go according to the plan.

Our drive didn’t go according to plan and we didn’t have a “Plan B.”

The route took us along Route 138, the Pearblossom Hwy., at the southern edge of the Antelope Valley. About midway to Victorville, we were to turn off onto Route 18 and continue eastbound to Victorville.

It was a shock then when we encountered a “Road Closed” sign. Just to make sure we wouldn’t try taking the turn, CalTrans lined the road on either side with concrete barriers—and continued to do so for miles.

What we didn’t know was that a rare a winter storm flooded the normally dry Mojave River washing out the bridge.

Our GPS did not like this, nor did we. The detour was taking us down to the Cajon Pass and San Bernardino--in the opposite direction to our quick charger in Victorville.

The GPS was telling us we had 30 miles to the charge station. Our range display, the Guess-O-Meer or GOM to Leaf owners, was telling us we had only 21 miles of range left. I knew the situation was even worse. The detour was taking us downhill. We would have to climb back up to get to Victorville. Our actual range remaining was less than displayed if we continued further.

I quickly passed from range anxiety to panic. Finally the concrete barriers ended and we could pull over to a convenience store. No charge station, no RV hook-ups, but at least we were off the road. Naturally, I couldn’t pull up Plugshare on my phone to search for alternative charge stations—even lowly Level 2 stations. Oy vey!

Time to pull out the map—the paper map.

We studied the map quickly. There appeared to be a number of paved and some unpaved roads that we could use to zig-zag our way northeastward towards Victorville. Our map wasn’t quite detailed enough, but it gave us an idea.

So we began our odyssey across the desert, hypermiling as much as possible often driving 35 mph and no more than 45 mph. Some of the roads reached dead ends—and we had to backtrack, eating ever more into our precious charge. But the range remaining on the GOM stayed steady, indicating that the hypermiling was working at extending our range.

We eventually reached a paved road that ran east and west. It had a lot of traffic, so I pulled onto the paved shoulder as often as possible to allow the traffic to pass on the left. That wasn’t good enough for one yokel in a late model pickup who was in a hurry. He laid on the horn and when that didn’t do the trick he gunned his engine and drove onto the right-hand side berm to race ahead. (You just can’t please some people.)

The GOM was holding steady and by now the GPS had caught up with us and was ticking off the miles to the charge station. I continued hypermiling as best I could with the traffic around Victorville.

At long last we pulled into the shopping center with a surprising 19% SOC. We’d driven an extra five miles over that planned and used nearly 15 kWh to reach Victorville. There was a Leaf charging, but there were two quick chargers on hand and we pulled right up and started charging with a collective sigh of relief.

Tail Wind

From Victorville we cleared the summit of Cajon Pass and started the long grade down to San Bernardino. This too was a new leg and after using more energy in the first three legs than planned I was particularly conscious of driving conservatively while trying to stay up with traffic. This leg was mostly downhill and we arrived at Calimesa after consuming only 10 kWh of the 12 estimated.

It was only 35 miles from here to our hotel in Palm Springs. I continued to drive in the slow-speed lane as much as possible after the day’s previous surprises.

It was Saturday night and the pace through the pass is furious as traffic from the LA basin races to the Indian casino in Banning.

We hadn’t been through the pass in years and the high-rise tower that marks the casino is so incongruous on the desert landscape. What were they thinking?

Riverside County must have relaxed their zoning standards since I last worked there. Several large wind turbines at a warehouse and a bottling plant sported corporate logos on their nacelles. The turbines were just as gaudy as the casino on the north side of the freeway.

San Gorgonio Pass is notorious for its wind and there was a powerful tail wind pushing us into Palm Springs. It was also mostly downhill as well. I was driving nearly 70 mph and using less than 10 kW.

We arrived with 55% charge, again well above that estimated. We checked in, had dinner, and saved charging for another day.

Return Trip

We were not going back the same way we’d just come. That was clear.

I’d chosen the route across the desert in part to avoid traffic, but also because many of the charge stations along the 210 were not working or otherwise out of service. Thus, using the limited number of working quick charge stations required some fairly long legs that we hadn’t done before.

We weren’t batting a very high percentage with the estimates from EVTripPlanner on the outbound trip so I was now quite dubious about the estimates inbound along the 210. We’d drive conservatively.

There was no headwind outbound to Calimesa, but it was all uphill and we consumed 2 kWh more than the 10 kWh estimated. We’re again off by 20%.

The next leg was long, 58 miles, over terrain we hadn’t traveled before. Turns out the route to Azusa is mostly downhill and we arrived 2 kWh ahead of estimate.

One advantage of driving an EV is that it forces you to travel differently. Driving today’s EVs require you to stop often, and in places you would never otherwise visit, such as Azusa.

We’ve never had a reason to visit Azusa, but there we were and we were happy to find that no one had ICEd the parking spots in front of the charger. We were even more pleased to find that the Blink charger worked flawlessly.

I’d seen a previous Plugshare visitor had commented that there was a coffee shop across the street. Indeed, there was and Mantra was a charming venue where they brewed a cappuccino every bit as good as Starbucks. It was worth the stop.

The next leg to Santa Clarita was long and partly uphill, calling for as much as 14 kWh. We came in on target and I could now start breathing easier.

It was a short 30-mile ascent to Palmdale and then on to Tehachapi and eventually Bakersfield.

We’d never done the 50-mile route to Tehachapi with the steep climb over Oak Creek Pass. While we arrived at the glider port with capacity to spare, 23%, that was only after we had cleared the summit. I knew the route well--I lived in Tehachapi for many years—and I knew what to expect. An inexperienced driver might panic watching the charge fall away rapidly at the steep climb to the summit.

It had been a long day and we were longing for a cup of tea, but the Raven’s Nest was closed so we huddled in the car while watching it charge at what now seemed like a painfully slow 6 kW per hour.

Eventually we packed up, picked up some take out falafel in town, then raced down the mountain to home. We knew the route, had done it several times before, and knew what to expect. We should only need 6 kWh to get home, plus a reserve.

We arrived after using only 17% charge—3.4 kWh. Could it be that EVTripPlanner underestimates consumption uphill and overestimates consumption downhill?

Temperature

We used quick charges eight times on this trip and it was clear that the temperature of the traction battery rose after each charge.

On a trip to LAX last summer I’d ran the temperature into the red on the temperature gauge by quick charging and driving the car hard. See Star-Crossed Trip: Bakersfield to LAX & Return. So I was aware that numerous quick charges could be a problem.

Outbound, battery temperature rose from the mid 50s when we left to 106 degrees Fahrenheit by Palm Springs. This was registered as 7 or 8 temperature bars on the dash. This time of year, the gauge typically reads 4 to 5 bars and up to 6 bars on a warm day.

On the return, battery temperature increased from 65 degrees to 107 degrees by the time we reached Tehachapi. When we arrived in Bakersfield it had dropped to 97 degrees.

Gids & Battery Health

Our 2015 Nissan Leaf is now more than a year old. We’ve driven the car some 8,800 miles. The traction battery probably started with a usable capacity of 22.6 kWh or 292 Gids, a unit of energy specific to the Leaf. We don’t know for sure because we only became able to read battery stats in August when I started using LeafSpy, an app for smartphones.

LeafSpy communicates with the Leafs onboard diagnostic computer via a device that plugs into the car’s OBD terminal.

Since I’ve been monitoring battery capacity, it has fallen from 287 Gids, or 22.2 kWh to 258 Gids, 20 kWh, when we left for Palm Springs. That is, we lost 2 kWh or 10% of the traction battery’s capacity since the onset of winter.

There’s a long ongoing discussion on mynissanleaf.com about the Leaf’s battery degradation and about how frequent quick charges appear to halt or reverse the decline on the 2015 model-year battery.

We used quick chargers eight times on this trip. It was clear that every time we used a quick charger, the traction battery’s state of health and its amphour capacity increased slightly. When we arrived in Palm Springs battery health had increased 2% from 88% to 90%. By the time we returned to Bakersfield, battery health had increased to 93%.

After arriving in Bakersfield, I began charging the car on our L2 EVSE. Before I went to bed I noticed that Gids had gone up to 272, gaining us 1 kWh over that when we had left. By the next morning Gids had fallen slightly back to 268.

For the moment, the 500-mile trip to Palm Springs and back gave us 0.8 kWh more in battery capacity than we had when we left. That’s a gain in range of 4 to 5 miles on a car with an official range of 84 miles. Only time will tell whether that’s an aberration or not.

All in all, our trip to Palm Springs was more stressful than necessary. With more quick chargers en route, we would have been able to drive more with traffic and still be assured of finding a quick charge station when we needed it. As it was, we made it to Palm Springs and back without a tow. Using today’s consumer-oriented EVs, that’s no small feat. Within a few years, it should be a regular occurrence

You can find more reports on our road trips at EV Trip Reports.

 


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