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Discussion Starter #1
While driving on the highway, I used mm to build up some battery charge. At this point I wanted to place the car in the hold mode to retain the charge for later use in the city. However, the hold mode was not available. Later, I realized that I had no charge left on the battery. Should I have just left the car in mm until I got in the city?
 

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I would not recommend using mountain mode for anything but mountains. Using the generator to recharge the battery is inefficient and unnecessary.
 

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If you switched to mountain mode when the SoC was already at a minimum (aka 0 EV miles remaining), then the car won't give you access to hold mode. Hold mode is essentially disabled until the car is recharged via grid, or restarted with some charge stored from mountain mode (requires at least one bar of charge, or >= 4 EV miles). However, leaving the car in mountain mode will allow the battery to charge until the minimum SoC reaches the "reserve" level as indicated by a red line. Once that point is reached, MM functions just like hold mode, just without the EV miles remaining listed.
 

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I would not recommend using mountain mode for anything but mountains. Using the generator to recharge the battery is inefficient and unnecessary.
Actually, using mm to recharge is not that inefficient if you run in on the highway and use the charge to drive around in the city. Once I had a depleted battery and ran mm mode on the highway for about 20 miles. I noticed that I was getting about 20 mpg during that portion. I was also able to get almost another 20 miles of low speed driving in the city from that charge. That's about 40 mpg. The volt is great when using the battery, but it''s annoying when running on gas in the city. The engine is constantly cycling on and off at a very high rpm, so it noticeable and loud. My old Prius was much better for running around town using gas. The Volt is a great car, but its weakness is running on gas in the city or in the hills. It feels underpowered when climbing hills.
 

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If you used MM to build up some charge. You should stop somewhere and restart the car so they show up as EV miles.

However, I do not recommend using MM for charging the battery, unless you plan to drive in some very mountainous areas. Using the gas engine to charge the battery is not as efficient as using it in REX mode.
 

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In my limited experience once you hit 0 on the battery meter the car locks in ICE mode. But that doesn't mean you can't charge for a bit via MM than go back to normal once traffic slows down (where these cars appear to excel in economy)
 

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Yes, leaving in Mountain Mode until town would have left the buffer at whatever percent that it usually does, like 40% for Gen 1, leaving EV range for around town. I can't comment on Hold since I don't have that feature.

The inefficiencies of MM are often over-exaggerated. I have tried driving around town, running out of gas completely, reset trip meter, and then use MM to recharge until 1 gallon is burned and switch back to normal and see how far I can drive until engine starts again and use charge sustaining mode to see how far I can drive on 1 gallon of fuel and I got 40 mpg in both cases for similar driving technique (I actually did slightly better in MM, but not statistically significant difference).

Mountain mode runs the engine hard until the buffer is where it should be, but this is actually a fairly efficient mode to run the engine for power generated vs fuel burned, so it doesn't do as bad as you think. However, it is generally cleaner to generate the electricity from the wall.

Ideally though, you would switch to mountain mode (or hold mode) before you depleted your range. Then it wouldn't have the extra inefficiency of charging it back up.

I like to run the engine in MM occasionally to burn off extra crap since it runs nice and hot. It avoids the burn smell you get sometimes when the engine starts infrequently or only runs due to temp.

Eric
 

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The introduction of Hold mode in the 2013 Volt complicated the power accounting system.

As the manual says, Electric Mode driving uses grid power stored in the battery and any regen that occurs while in Electric Mode. The energy usage screen records this as Electric Miles and kWh Used (= grid power used less regen put back into the battery). Everything else is Extended Range Mode, displayed as Gas Miles and Gas Used, including miles driven when the ICE is running, and miles driven on battery power put there from regen that occurs while in Extended Range Mode and battery power put there by Mountain Mode recharging.

Hold mode preserves grid power for later use. If you switch to MM when the battery state of charge is below the MM-maintained level (~4 bars for a Gen 1 Volt, ~2 bars for Gen 2) but above the fully depleted level, MM will recharge the battery to the MM-maintained level. During the process, MM-recharged power increases the battery’s soc above the level of the remaining grid power. If you then switch back to Normal, neither Hold nor Electric mode should be available until the battery soc drops back down to the existing grid power level. Yes, you will drive on battery power, but it should register as Gas Miles because the power was put there by running the generator. Once the MM-recharged power has been used and the soc is back to the grid power only level, Hold or Electric Mode should become available.

Note: 2011/2012 Volts had a glitch that under the above circumstances, switching to Normal would immediately switch the car back to showing the battery icon and recording the miles as Electric Miles. Using this MM-recharged power, however, would not add to the kWh Used number.

If you instead switch to MM after the battery is fully depleted, you won’t have any grid power to "save for later use" until you plug into the grid and recharge. If you switch back to Normal after MM recharges the battery from fully depleted, the soc is, indeed, above the minimum level, but there is no grid power there, and Hold should not be available, and the ICE should continue to operate as if the battery were fully depleted (even though the MM-maintained buffer now exists), and miles should be recorded as Gas Miles.

However, if you stop and turn the Volt off and back on again after using MM to recharge, the accounting gets confused. The computer is now told that the battery’s soc is above the minimum level, and so the car proceeds on battery power and records the distances as Electric Miles. The kWh Used number, however, should not increase while MM-recharged power is being used (it’s not grid power). I drive a 2012 Volt with no Hold mode, so I cannot test to see if turning the car off and on again will enable the use of Hold mode to "save MM-recharged power" for later use.
 

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Whatever you do, dont' think that you are saving any energy by generating your own electricity. If you want to do this in order to have blissful ICE free driving for a little while, then fine. But it's been shown time and time again that Volting doesn't work (it might in very limited circumstances, but I have yet to get it to work for me).
 

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Whatever you do, dont' think that you are saving any energy by generating your own electricity. If you want to do this in order to have blissful ICE free driving for a little while, then fine. But it's been shown time and time again that Volting doesn't work (it might in very limited circumstances, but I have yet to get it to work for me).
Unless you're paying less than about a buck fifty for a gallon of gas. Which I suppose is conceivable, considering that Oklahoma's paying about $2.07 these days...
 

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Unless you're paying less than about a buck fifty for a gallon of gas. Which I suppose is conceivable, considering that Oklahoma's paying about $2.07 these days...
With my electric rates, gas would need to be less than 97 cents per gallon before it makes more sense to drive on Dino juice than plug in. And even if that were the case, I like giving OPEC the finger. I'm only giving one finger right now by charging at home, but I plan to flip them twin birds when I have the house paid off and could care less about paying $8 per day, about $160 per month to charge at work at the nearest overpriced chargepoint.
 

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With our 2016 Volt we use hold mode more so than mountain mode. If we plan on going to Portland Oregon for the day I just drive on electric and than at 20 miles or so switch to hold mode. Once in the city area we can switch to normal, electric mode for all of our city driving.
 

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With our 2016 Volt we use hold mode more so than mountain mode. If we plan on going to Portland Oregon for the day I just drive on electric and than at 20 miles or so switch to hold mode. Once in the city area we can switch to normal, electric mode for all of our city driving.
The MM in the Gen 2 Volt isn't as good as the Gen 1 Volt. In the Gen 2, MM maintains the battery at 14% charge (as displayed by the MyChevrolet and RemoteLink apps). This works out to about a 2 kWh reserve. While two green bars show, after turning the car back to Normal Mode the second bar almost immediately disappears, and you get maybe 7-8 miles of electric range.

From what I have read here, the Gen 1 MM reserve is more like 40%, or about 4 kWh. (Is 40% what MyChevrolet/RemoteLink apps show? Or just a guess because 4 bars of 10 are displayed? Be nice if a Gen 1 owner could confirm.)

For its intended purpose, climbing mountains, the revised Gen 2 setting may be fine though. This because the Gen 2 has a more powerful ICE than Gen 1 had, and perhaps because of the improvements in the transaxle design allow better efficiency as well.
 

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From what I have read here, the Gen 1 MM reserve is more like 40%, or about 4 kWh. (Is 40% what MyChevrolet/RemoteLink apps show? Or just a guess because 4 bars of 10 are displayed? Be nice if a Gen 1 owner could confirm.)
My 2015 gains 5 out of 10 bars in MM.
 

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My 2015 gains 5 out of 10 bars in MM.
What % of charge does the myChevrolet Vehicle Status display indicate? With the Gen 2, it is pretty solidly at 14% every time I've tried it.
 
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