Mountain Mode not needed (Gen 2)

6077 Views 25 Replies 11 Participants Last post by wordptom, Oct 5, 2018

obermd

Discussion Starter · Oct 1, 2018 (Edited)

It's leaf peeping season in Colorado, so this morning I filled my tank and headed for the mountains. I live at 5,700 ft above sea level and ran out of battery after a little over 47 miles and a net climb of 2,800 ft. I stayed in Normal mode the entire loop, driving over Kenosha Pass at 10,000 ft, Independence Pass at 12,095 ft, Vail Pass at 10,662 ft, and through the eastbound bore of the Eisenhower tunnel at 11,158 ft. I drove the posted speed limit the entire way and kept my Volt in Normal mode the entire time. Kenosha, Vail, and Eisenhower approaches are posted 65 MPH. Kenosha isn't that steep so my car was only pulling about 20 KW on the climb. Climbing Vail and Eisenhower my car was running about 40-45 KW power output and the ICE was happily screaming along. I was even able to accelerate up both passes to about 80 MPH using the Normal mode "low" buffer in the battery. The descent from Independence Pass to Aspen actually resulted in three bars of power being regenerated. When I got to down to Georgetown I got off I-70 for a bathroom break and had one bar of battery from the descent. My car correctly identified it as "gas" power and allocated it to the gas fuel economy number even after I restarted the engine even though the Classic Enhanced display showed battery power only upon restart.

Here's the Energy Usage display when I got home.

Electronics Multimedia Technology Electronic device Gps navigation device

The leaves were stunning with a variety of greens, yellows, and reds throughout the drive.

One other note: I was passed on I-70 by a CDOT (Colorado Department of Transportation) painted Chevy Bolt. Interesting...

See less See more

Save

1 - 4 of 26 Posts

wordptom

· #11 · Oct 2, 2018

obermd said:
It's leaf peeping season in Colorado, so this morning I filled my tank and headed for the mountains. I live at 5,700 ft above sea level and ran out of battery after a little over 47 miles and a net climb of 2,800 ft. I stayed in Normal mode the entire loop, driving over Kenosha Pass at 10,000 ft, Independence Pass at 12,095 ft, Vail Pass at 10,662 ft, and through the eastbound bore of the Eisenhower tunnel at 11,158 ft. I drove the posted speed limit the entire way and kept my Volt in Normal mode the entire time. Kenosha, Vail, and Eisenhower approaches are posted 65 MPH. Kenosha isn't that steep so my car was only pulling about 20 KW on the climb. Climbing Vail and Eisenhower my car was running about 40-45 KW power output and the ICE was happily screaming along. I was even able to accelerate up both passes to about 80 MPH using the Normal mode "low" buffer in the battery. The descent from Independence Pass to Aspen actually resulted in three bars of power being regenerated. When I got to down to Georgetown I got off I-70 for a bathroom break and had one bar of battery from the descent. My car correctly identified it as "gas" power and allocated it to the gas fuel economy number even after I restarted the engine even though the Classic Enhanced display showed battery power only upon restart.

Here's the Energy Usage display when I got home.
View attachment 155691

The leaves were stunning with a variety of greens, yellows, and reds throughout the drive.

One other note: I was passed on I-70 by a CDOT (Colorado Department of Transportation) painted Chevy Bolt. Interesting...

That’s a fascinating energy usage display that shows the Volt calculations are completely ignoring the energy content of any regen you created and used on this trip.

The Gen 2 window sticker rates the car at 106 MPGe, i.e., it can travel 106 ev miles using the energy content of 33.7 kWh of power from the wall (= energy content of 1 gallon of gas = 1 Ge). The 53 ev miles per charge rating indicates one full charge uses 16.85 kWh, or 0.5 Ge, from the wall.

On this trip, you drove 47.3 miles on the full charge, using 0.5 Ge of electric fuel from the wall, and the display shows your Trip MPGe = (47.3/0.5) = 94.6 MPGe.

You also drove 340.4 miles using 6.74 Ge of gas, for a total of 387.7 miles using (6.74 + 0.5 =) 7.24 Ge of energy equivalent fuel. The display shows your combined trip MPGe = (387.7/7.24) = 53.6 MPGe.

The energy content of the regen you created and used during the trip is clearly not factored into the energy usage display numbers at all.

Save

wordptom

· #13 · Oct 2, 2018

That’s my point: your Volt energy usage display is indicating you drove 340.4 gas miles using the energy content of 6.74 gallons of gas.

Your calculations suggest it is more likely you drove those 340.4 gas miles using the energy content of 6.74 gallons of gas (6.74 Ge used to drive 283.1 gas miles) plus the energy content of 15.7 kWh of regen electricity (an additional ~0.5 Ge of fuel used to drive 53.7 gas miles).

The total energy content used to drive the Gas Miles was greater than the energy content of the Gas Used to drive those miles.

Similarly, the total energy content used to drive the 47.3 Electric Miles was greater than the energy content of one full charge of grid electricity (0.5Ge).

The Volt’s kWh Used number is a net calculation of grid power used less regen put back into the battery. How much regen did your Volt create and use while you were driving Electric Miles?

It would be informative if the energy usage screen had a display for "Regen kWh," and even better if it recorded both Electric and Gas regen kWh.

See less See more

Save

wordptom

· #18 · Oct 3, 2018

Barry said:
I think you are trying to count the regen electricity wrong. The only energy inputs into the car are gas and the grid electricity that is supplied by an EVSE. The regen is not an energy input into the car. It is just the temporary storage of momentum or potential energy that came from either gas or grid power.

Seems to me that if you disable the Volt’s regenerative braking system and rely on the friction brakes, you will reduce the Volt’s total trip range without reducing the amount of grid electricity and gas used. That would seem to indicate that regen provides additional range and should be included as fuel used to drive the recorded distances when calculating fuel mileage.

However, electric miles driven using regen battery power (created while driving in Extended Range Mode) and gas miles driven using gas when the engine is running are combined in the single Gas Miles category (= distances driven not using grid electricity or regen created while driving on grid electricity). We have no method of including the regen as fuel consumed when calculating the Volt’s gas mileage.

Save

wordptom

· #26 · Oct 5, 2018

Nanabanana said:
I really need to learn how to drive my Volt. You folks have opened my eyes. I have been driving my car since 2012 and I rarely use L or switch back in forth between the 2. Can you do this while you are moving? Wouldn't it damage the transmission. Obviously I have a Generation 1. I live 1.3 miles from my job. I drive to and from everyday. I do take my grandson to school and pick him up from afterschool daycare. And what is ICE? I am really not knowledgeable about this machine. I love my car...

"D" and "L" aren’t gear settings, they are regen level settings that take effect in the Gen 1 Volt only after you take your foot off the accelerator. You don’t "drive" in Low, you "slow down" in Low... D and L are settings for determining how aggressively you want your Volt to reduce your momentum whenever you take your foot off the accelerator... do you want the car to "coast" in D (relatively light regen) or do you want to quickly reduce your Volt’s momentum by engaging the stronger L-level regen each time you take your foot off the accelerator?

Regenerative braking is an alternative to friction braking in a Volt, and it doesn’t matter if you are driving in Electric Mode using battery power or in Extended Range Mode using gas with the internal combustion engine (ICE) running... once regen puts power into the battery, however, the distance you drive on that regen battery power will be classified under the driving mode you were in when you created it... driving downhill with a fully depleted battery, or in Hold Mode (not available in the 2011/2012 Volt), will give you regen-battery-powered Gas Miles once you reach the bottom of the hill and start using that regen. If you drive down the same hill in Electric Mode, the regen-battery-powered miles will be recorded as Electric Miles.

See less See more

Save

1 - 4 of 26 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.

Top Contributors this Month