Range Anxiety Driving a Gas Rig

Mar 21, 2019

How range anxiety can be experienced while driving a gas powered vehicle even with a large gas tank under certain circumstances.

On Wednesday March 13th we left on a trip to Indian Wells, CA to attend the Paribas Tennis Tournament which we had been planning on for quite a few years. The trip was part of our bucket list of things to do while we still are healthy enough to do them.

We were towing a 9K lbs. 5th wheel trailer with a 2014 Ford F-150 XLT PU with a 3.5 liter Eco Boost engine. I have written about this configuration before in my blog titled “Our Fossil Fuel Total Eclipse Vacation”. The purpose of this blog is not to outline carbon emissions but rather to show how “Range Anxiety” is a problem attending even the use of gasoline powered vehicles.

Our truck which barely averages 18 mpg in normal driving, maybe a bit more in highway driving has a 36 gallon gas tank, which can routinely yield over 600 miles of range. There just is not much in the way of “Range Anxiety” to be experienced here in normal driving.

However hitch up a 30 foot long 5th wheel travel trailer weighing just over 9,000 lbs. (with gear), having 100 square feet of frontal area, and matters become a little different. Getting anywhere from 8 mpg to 9 mpg towing this rig reduces your range (with a built in safety margin of 4 gallons) to anywhere between 260 miles to 290 miles tops.

Throw in windy conditions, and the search for mid-grade gasoline at reasonable price, the need for a gas station you can get in and out of with such a rig, and “Range Anxiety can rear its ugly head. We definitely encountered the beast on this trip.

On the morning we were set to leave some dam fool set off a Typhoon Bomb making its way to the northeast just north of our location in Las Cruces, NM. The counterclockwise winds of this low pressure area generated a wind field for hundreds of miles causing us to encounter from 20 mph to 30 mph headwinds traveling west towards Arizona.

Nothing much we could do except slow down and try to get on the road early before the wind reached their maximum speeds. This we did leaving the house at 7:45 AM, getting on I-10 West doing no more than 62 mph, or 100 kph. Even so, as you can imagine a 20 mph headwind can amount to an 80 mph ground speed, which would increase fuel consumption dramatically.

West of Deming, NM the winds begin to pick up and we had to slow down to 55 mph. Our GOM (Guess-O Meter) was returning readouts in the 6 to 7 mpg range. By the time we got to Lordsburg, NM the winds had picked up even more, but we had crossed the Continental Divide just west of Deming so the downhill grade was helping us. We fueled up in Lordsburg at the Loves Station pumping 19.993 gallons for $54.36 for 150.5 miles. That is 7.6 mpg rounded up only slightly.

This is an early stop because there just aren’t good places to fuel up between our home and Tucson, Arizona other than Lordsburg. Tucson is too far to make on one tank and our campsite Picacho Peak State Park is about 40 miles northwest of Tucson. Our next fuel stop was in east Tucson, AZ.

Leaving Lordsburg we begin to not only encounter wind gust up to 30 mph and also quartering winds. This slowed us down to 50 mph and slower on occasion. To make it to Tucson you have to climb the Chiricahua’s which is more hills climbing before you descend into Benson, AZ. Then you have climb out of the basin of Benson, AZ to go to Tucson.

At Tucson we took on 20.809 gallons of fuel for $49.30, for 150.2 miles of travel. This yields a figure of 7.2 mpg, so you can see, I am not kidding about conditions being of the white knuckle code red varieties. Then we went on to our campsite arriving early in the afternoon. There really was a benefit to being the early bird to beat the wind here.

The next day we decided to enter California through Yuma, AZ gassing up with cheaper gasoline than is available in California, so we could limit our purchases of gas in California. This was a stretch as there isn’t much in the way of civilization along I-8 until you get to Yuma. We pumped 30.335 gallons for 251.5 miles of travel netting us 8.27 mpg. This was definitely a better result.

Wishful thinking here, we stopped at El Centro, CA and put 8.556 gallons of gas in the truck for $27.20 to defer gassing up again until we got to the Quartzsite/Ehrenberg border on our way home. This 66.6 mile run yielded us 7.78 mpg. Driving miles around Yuma, AZ to find a Walmart hadn’t helped us here.

On the way to Indian Wells, CA we passed by the Salton Sea which is at -250 feet of elevation. This is quite some dramatic elevation changes. We had traveled from our home at 4,000 ft. across the Continental Divide at 6,800 ft. down to the Salton Sea at negative 250 feet. Of course the denser air at sea level comes with a mpg penalty also.

We thoroughly enjoyed our tennis vacation at the Indian Wells Paribus. We got to see both Roger Federer and Rafael Nada play tennis, but not each other. On Saturday they were scheduled to play in a semifinal playoff. Our $70 tickets magically had morphed in tickets worth $350, but it was not to be. Nadal who was experiencing knee problems the day before in the match he won withdrew from the match, so Federer had a walk-over.

On Sunday we hooked up and headed to the border. My grand theory of buying as little gas as we could in California didn’t pan out. We bought 6 gallons of gas in Indian Wells for insurance. When we got to the border it turned out that there were Valero stations on the Quartzsite, CA side which we had a card for buying gas that we needed to use.

In Quartzsite we bought 20.085 (plus the 5.999 gallons = 26.084) for $68.27 + $19.37 = $87.69. So for 212.3 miles of travel we netted 8.13 mpg. We had some driving around unhitched at the tournament, but I estimate that to be no more than about 18 miles.

Our next run was our best to our campsite at Picacho Peak thence to NE Tucson to fill up. We traveled a total of 272.9 miles using 32.07 gallons costing $83.20. This was for a whopping 8.5 mpg in nice weather. We had used the Phoenix bypass so we never did have to go through Phoenix, AZ.

The trip home on Monday March 18th consisted of another stop in Lordsburg, NM for 20.4 gallons and a fill up the day after we got home of 16 gallons of 86 octane (as we are no longer towing). The total cost was $90.20 for 36.408 gallons for 295.1 miles. This is 8.1 mpg for both fuel stops averaged together.

We had traveled a total of 1,380 miles for our burning 174 gallons of gasoline for a net average of 7.93 mpg. So, as you can see having a 36 gallon gas tank with 4.026 million BTU’s of on board energy available can’t eliminate “Range Anxiety” under all circumstances. Especially when your vehicle technology only uses 20% of the available energy to do its work, it is concerning when there is so much work to do.

When you are towing a rig like this in the desert southwest with good sources of fuel being irregularly spaced, with prices all over the map (from $2.329 to $3.799 a gallon) with headwinds sapping fuel economy down to 5.5 mpg and your gas buddy app being less than helpful about the price of mid-grade gasoline you just might experience a little range anxiety driving a gasoline powered tow vehicle.

It is not a perfect world but this kind of experience had me dreaming of a 400 mile to 600 mile range Rivian style Electric Truck set up to tow a dream 5th wheel trailer with its own battery packs, powering an electric assist motor on the trailer. Imagine such a trailer with a boat tail appliance to reduce drag, netting you a 10 mpg equivalent gas towing experience.

By the numbers, you could transform the energy requirements to as little at 35 mpg-e for towing such a rig, with an electric tow vehicle. Let’s say you had a 180 kWh battery in the truck and a 30 kWh battery in the trailer for the assist for hills, starting, and hitch load reduction. You might keep 10% in reserve which would limit you to 190 kWh for use on the road.

At 35 mpg-e this kind of storage would amount to 202 miles of range. You would charge at night while camping, so one charging stop per day at V-3 super charging site would suffice. Imagine this would be an extended lunch, so possibly an 80% charge, requiring no more than 90 minutes would suffice. This all sounds doable, and if powered with renewable energy, it would be golden.

None of this exists yet, but it could. The electric trucks are coming and the Germans showed off an electric assist caravan at one of their RV shows last year. What I have just outlined here could exist, so I will just leave it to your imagination. Not everything we currently observe and experience in the world as of 2019 has to be, and it is soon to be surpassed by disruptive electric drive technology arriving now.

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