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Slightly different scenario - matches the thread title. I moved into a condo rental that lacks any access to at home charging (my state has a law that entitles units to establish separate metering for their assigned parking, but I'm a renter). My employer also has zero outlets that I can use for even L1 charging. I occasionally use free L2 charging ~1mi from my garage, but typically am driving in CS/normal mode for the last ~10 months.

Any advice on whether there should be a long term benefit to keeping the car in mountain mode (MM) to maintain a ~45% SOC vs. the ~20-30% SOC in CS/normal? My 2013 Volt with 63K miles still has experienced minimal operational (~<5%) range degradation. I believe the battery would be best served kept at the MM SOC vs. the low end normal mode. Anyone have any input? I haven't seen this specific question on optimal gas-only operation for vehicle longevity, thanks!
It wouldn't hurt anything to run in MM all the time, but there is no long term benefit either. Mountain Mode will kill your efficiency and gas mileage too. It's much cheaper and efficient to charge your Volt with an EVSE than to charge it using MM. Plus, switching to MM every time you start the vehicle will wear out the Mode switch. Many people who drive in Sport mode all the time have found this to be true.
 

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Thanks for the reply. As stated, unfortunately I cannot charge at home or at work. Knowing this, it seems that running permanent MM vs. CS would yield a marginal benefit, I just don't know how large that marginal is.

A second thought that I had and am beginning to test is using MM tactically as a way to eek out a better overall MPGe performance. I drive ~20 miles each way (remember, I cannot charge), and ~5-15 of those miles are city/lower speed stop & go traffic. It seems like if I use MM to tactically recharge the battery during my 55-70 mph highway stretches I can obtain enough charge to use normal mode when it is optimal. I'll be doing some data gathering and will report back here. I saw several threads dedicated to this but it seems that most are for long routes or situations where the driver still charges when at home.

It wouldn't hurt anything to run in MM all the time, but there is no long term benefit either. Mountain Mode will kill your efficiency and gas mileage too. It's much cheaper and efficient to charge your Volt with an EVSE than to charge it using MM. Plus, switching to MM every time you start the vehicle will wear out the Mode switch. Many people who drive in Sport mode all the time have found this to be true.
 

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It wouldn't hurt anything to run in MM all the time, but there is no long term benefit either. Mountain Mode will kill your efficiency and gas mileage too. It's much cheaper and efficient to charge your Volt with an EVSE than to charge it using MM. Plus, switching to MM every time you start the vehicle will wear out the Mode switch. Many people who drive in Sport mode all the time have found this to be true.
Mountain Mode’s function is to increase (temporarily) the Volt’s "switch to gas" state of charge so the car will have more borrowable power when you anticipate driving in high power demand driving conditions. Hold Mode’s function is to hold on to the remaining battery charge for use later. If you switch into MM with a full charge, the Volt remains in Electric Mode until the SOC drops to the new, temporarily increased "switch to gas" point. After that point, the gas consumption is that of normal Extended Range Mode driving. The only time MM uses "extra" gas is when you don’t turn it on until the battery is fully depleted, or already below the MM-maintained SOC.

The thread title is Driving on Gas Exclusively. Uberkikz11 has been driving his 2013 Volt on gas almost exclusively for several months because he has no regular access to recharging facilities, and is wondering if there is any benefit to battery longevity if you keep the battery’s SOC at the MM-maintained level (~45% raw SOC level) by driving with Mountain Mode switched on, rather than leaving it at the usual "switch to gas" level (~20-22% raw SOC).

IOW is it better for battery life to keep the Volt’s battery at ~45% raw SOC rather than to keep it at ~22% raw SOC, or would the SOC need to be kept much lower or higher than either of those to have a significant impact on battery life? I myself don’t know.

A second thought that I had and am beginning to test is using MM tactically as a way to eek out a better overall MPGe performance.
No, no, no. Perhaps you are thinking of MPG numbers (minimizing gas use in a round trip commute). MPGe calculations don’t include the use of regen or the use of MM-recharged battery power as electric fuel. Each time you fully recharge a fully depleted 2013 Volt battery, you pull (38 miles per charge/98 MPGe =) 0.39 Ge, or ~13.1 kWh of power from the wall. 65% of the 2103's 16.5 kWh full capacity battery = ~10.7 kWh, the usable power in a full charge (~2.4 kWh for charging losses). Your 2013's MPGe is calculated by seeing how far you can drive on a full charge (0.39 Ge), using ~10.7 kWh of usable grid power on the energy usage screen as the equivalent of a full charge. Any regen you get while driving and any use of MM-recharged battery power isn’t added to that 0.39 Ge per 10.7 kWh of usable power when calculating the MPGe.

I, for example, once drove 89 electric miles in my 2012 Volt, using 9.8 kWh of power (= 9.8/10.4 of a full charge), according to the energy usage display (I used Mountain Mode to recharge, and since it didn’t come from the wall plug, it wasn’t counted as fuel). That’s 89 electric miles using 0.35 Ge, or ~254 MPGe (car rated at 94 MPGe)!
 

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TL;DR: I can't charge at home or work. Instead of Normal/CS mode for ~40mi mixd commute should I use MM when cruising at highway speed and use the battery in stop-go /city driving? I'm testing and will report my findings.

Mountain Mode’s function is to increase (temporarily) the Volt’s "switch to gas" state of charge so the car will have more borrowable power when you anticipate driving in high power demand driving conditions. Hold Mode’s function is to hold on to the remaining battery charge for use later. If you switch into MM with a full charge, the Volt remains in Electric Mode until the SOC drops to the new, temporarily increased "switch to gas" point. After that point, the gas consumption is that of normal Extended Range Mode driving. The only time MM uses "extra" gas is when you don’t turn it on until the battery is fully depleted, or already below the MM-maintained SOC.

The thread title is Driving on Gas Exclusively. Uberkikz11 has been driving his 2013 Volt on gas almost exclusively for several months because he has no regular access to recharging facilities, and is wondering if there is any benefit to battery longevity if you keep the battery’s SOC at the MM-maintained level (~45% raw SOC level) by driving with Mountain Mode switched on, rather than leaving it at the usual "switch to gas" level (~20-22% raw SOC).

IOW is it better for battery life to keep the Volt’s battery at ~45% raw SOC rather than to keep it at ~22% raw SOC, or would the SOC need to be kept much lower or higher than either of those to have a significant impact on battery life? I myself don’t know.



No, no, no. Perhaps you are thinking of MPG numbers (minimizing gas use in a round trip commute). MPGe calculations don’t include the use of regen or the use of MM-recharged battery power as electric fuel. Each time you fully recharge a fully depleted 2013 Volt battery, you pull (38 miles per charge/98 MPGe =) 0.39 Ge, or ~13.1 kWh of power from the wall. 65% of the 2103's 16.5 kWh full capacity battery = ~10.7 kWh, the usable power in a full charge (~2.4 kWh for charging losses). Your 2013's MPGe is calculated by seeing how far you can drive on a full charge (0.39 Ge), using ~10.7 kWh of usable grid power on the energy usage screen as the equivalent of a full charge. Any regen you get while driving and any use of MM-recharged battery power isn’t added to that 0.39 Ge per 10.7 kWh of usable power when calculating the MPGe.

I, for example, once drove 89 electric miles in my 2012 Volt, using 9.8 kWh of power (= 9.8/10.4 of a full charge), according to the energy usage display (I used Mountain Mode to recharge, and since it didn’t come from the wall plug, it wasn’t counted as fuel). That’s 89 electric miles using 0.35 Ge, or ~254 MPGe (car rated at 94 MPGe)!
Since I have to start every day without charging I'm testing this operating model on my work commute for the next few weeks and will report my findings. Over the past few days I've found what appears to be a modestly improved net MPG using MM at highway speed and normal operation in city/stop-go driving with the charge that was generated:

End prior day with ~6-7mi range remaining
START
~6mi city driving to highway entrance (zero range remaining)
~12mi highway driving in MM at ~55-73, (~17mi electric range generated)
~2mi city driving to work in normal mode, including highway deceleration (~15mi electric range remaining)
WORK
~2mi city driving to highway in normal mode (~13mi electric range remaining)
~5mi in stop-go city driving on highway in normal mode (~8mi electric range remaining)
~8mi in highway speed driving on highway in MM at ~55-73 (~11mi electric range generated, ~19mi electric range remaining)
~5mi city driving in normal mode (~14mi electric range remaining)

Note this is resulting in a small gain over the course of the week, which may end up being the case, this is a rough-ed out representation of my commute in Miami which is very much YMMV, both weather, traffic, and (slightly) route options, so I may be able to further modify and maintain balance in running optimally as needed.
 

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After ~2 weeks of testing my findings support the thesis that optimal (MM highway, normal in city) usage of mountain mode/normal mode vs. purely driving in normal mode yields fuel economy improvement in the 10-20% range.
 

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After ~2 weeks of testing my findings support the thesis that optimal (MM highway, normal in city) usage of mountain mode/normal mode vs. purely driving in normal mode yields fuel economy improvement in the 10-20% range.
Can you give us numbers showing you’ve reduced your Gas Used by 10-20% by selectively using Mountain Mode on your commute?

If you are not recharging at all from the wall during the week, then each round trip, 20-mile-each-way, commute in your 2013 Volt, at the car’s 37 mpg window sticker ratings, should consume about 1 gallon of gas, more or less. With no grid power usage at all, all of your miles, including any MM-recharged Electric Miles, originate from the use of gas. Any fuel economy improvements shown for a round-trip, 40 mile commute would show up in the Gas Used column as a decrease in gas consumption.

If those numbers have gone down, perhaps you are demonstrating my assertion that by using Mountain Mode to convert a given quantity of gas (~0.36 gallons for a Gen 1 Volt) into a given amount of battery charge (~4 bars), when you then use the energy content of that battery charge to drive in good electric mileage but poor gas mileage driving conditions (for example, in stop and go traffic), you’ll drive further on that given quantity of gas than if you had used the energy content of that gas itself to drive in normal CS mode with the engine running.

Using MM will certainly improve your electric mileage, because once you turn the car off after recharging with MM (for example, once you arrive at work), when you turn the car on again, that battery power gets recorded as Electric miles without recording any kWh Used when doing so... with the help of MM-recharged power, as I mentioned in an earlier comment, I once drove my 2012 Volt 89 Electric Miles with only 9.8 kWh Used (9.1 mi/kWh!).
 

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I had zero battery after a day at Ikea and Costco. Filled up the Volt (2282 miles, 5.4g :cool: ) for the 71.2 mile ride home.

Put the Volt in MM during times I was traveling 55mph and normal(L) when in towns. Arriving at home using only 1.3 gallons of gas, a staggering 54.8mpg. While I was being as conservative as I could, we did have a few hundred pounds of food and Ikea crap, I find that MPG intriguing.
 

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Hard to give you firm numbers because the Volt's system seems to struggle with accurate counting at times. For example, last week I began the work week fully charged and then tactically used hold/regular on Monday/Tuesday and MM/regular the balance of the week. All my driving was from home and work, ~41-42ish mi RT. By the end of the week the car display registered I had driven 210 miles. The system indicated I had used 12.2 kWh and 3.8 gal of gas to cover 50mi electric and 160mi on gas...
 

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D96098FA-813E-44A2-8521-30FFA0B02E84_1563403222132.jpg D96098FA-813E-44A2-8521-30FFA0B02E84_1563403222132.jpg D96098FA-813E-44A2-8521-30FFA0B02E84_1563403222132.jpg
Hard to give you firm numbers because the Volt's system seems to struggle with accurate counting at times. For example, last week I began the work week fully charged and then tactically used hold/regular on Monday/Tuesday and MM/regular the balance of the week. All my driving was from home and work, ~41-42ish mi RT. By the end of the week the car display registered I had driven 210 miles. The system indicated I had used 12.2 kWh and 3.8 gal of gas to cover 50mi electric and 160mi on gas...
FYI the photos below are from a full charge Monday morning through sitting in my parking garage at home Wednesday. Note the MPG if you bring the 9 in storage into the equation is ~44. I drive in Miami with the A/C on eco @ 73. My prior MPG average driving in normal mode for a year was roughly 39-40, always fueling with Shell or Costco premium fuel.
 

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If you are driving on gas all the time (assumes no home charging, apt. etc.) not sure why you would drive a PHEV instead of hybrid as you are paying for the complexity but not getting any of the advantages.
 

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If you are driving on gas all the time (assumes no home charging, apt. etc.) not sure why you would drive a PHEV instead of hybrid as you are paying for the complexity but not getting any of the advantages.
I bought the vehicle new when I owned a house. The used vehicle transaction costs & risks of acquiring an unknown commodity outweigh the optionality of me driving my 2013 64k mi well maintained vehicle until at least the Voltec warranty expires. The marginal fuel benefit is very minor (<$150/yr) going from ~40mpg premium to ~45mpg regular fuel w/ 15k mi/yr.
 

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If you are driving on gas all the time (assumes no home charging, apt. etc.) not sure why you would drive a PHEV instead of hybrid as you are paying for the complexity but not getting any of the advantages.
Ah, but in a Gen 1 Volt, he is getting the electric car performance advantages.

The OP’s description of his 20-mile-to-work and 20-mile-home-again commute in #24 above includes a lot of suburban driving, stop and go driving, speeding up and slowing down on the freeway driving, i.e., conditions in which he is likely to be driving his 2013 Volt in Extended Range Mode, one-motor configuration. GM calls this "electric like" driving, where the engine’s function is to generate fuel. For the portion of any CS drive where the Gen 1 Volt is not smoothly cruising in split-power configuration for efficiency - perhaps around 80% for this commute? - the driver is experiencing 100% all-electric driving. The motor is fueled by gas-generated electricity.

Even when his 2013 Volt’s engine is running, one-motor configuration provides the OP with the same "all-electric car" performance, using gas-generated electricity, on his commute that he would have if he still had regular access to charging facilities and could start the day will a full charge. That’s something you don’t have in a Gen 2 Volt.
 

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Hard to give you firm numbers because the Volt's system seems to struggle with accurate counting at times...
Your Volt struggles with accurate counting because your are experimenting with Mountain Mode.

The energy usage screen on the center console attempts to separate Electric Mode performance (Electric Miles/kWh Used) from Extended Range Mode performance (Gas Miles/Gas Used). Electric Miles is intended to designate the miles driven on the grid power stored in the battery when you charge it.

Once your battery is depleted, you have no remaining grid power, and that should be the end of the Electric Mile counting until you recharge the battery.

If, however, you then switch your Gen 1 Volt to Mountain Mode, the engine will burn extra gas to charge the battery back up to the ~4 bar level (this is designed to provide a battery buffer for use if needed when driving up mountains).

If you then turn off the car (for example, you switched to MM on the way to work, the battery recharged, and now you’ve reached work), when you turn on the car to go home that night, the computer recognizes the battery’s SOC is above the switch to gas point, and considers this as being in Electric Mode. You drive home, the distance is recorded as Electric Miles. It’s not grid power, so the computer doesn’t change the kWh Used number.

As far as statistics are concerned, your energy usage display now includes too many Electric Miles for the kWh Used shown there, and too few Gas Miles for the Gas Used shown there. You don’t know how many of the Electric Miles were driven on MM-recharged battery power (miles made possible by using gas) and how many Gas Miles were credited to the Electric Miles category. And there is no way to correct this.

That’s what is going to make it difficult to determine your daily driving efficiency and to compare using different driving techniques on different days (Hold/normal vs MM/normal)... especially if you include random amounts of from the wall charging during the week...
 
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