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I have a Gen 1 (2014) Volt and love it.

I've read two articles recently on the ending of Volt production in 2019.

In each article, they say that when electric range is depleted - the internal combustion engine starts and recharges the propulsion battery.

I am having trouble with that. In my Gen 1, the only way to recharge the propulsion battery is 'regen' while slowing and braking, and then plugging it in at home.

So: Does the Gen 2 Volt actually recharge the propulsion battery? If so, there'd be no need to plug it in. Right?
 

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Dwight: As Scott said it essentially operates the same as the gen 1. Gen 2 can “recharge” the battery to a limited extent using mountain mode, but it’s extremely inefficient, and it only charges the main battery up to about 15%. The Gen 2 also of course can supply electric power to the motors in charge sustaining mode indefinitely as long as there’s gas in the tank. And that’s how the Volt operates on a long trip, same as the 14.


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Dwight: As Scott said it essentially operates the same as the gen 1. Gen 2 can “recharge” the battery to a limited extent using mountain mode, but it’s extremely inefficient, and it only charges the main battery up to about 15%. The Gen 2 also of course can supply electric power to the motors in charge sustaining mode indefinitely as long as there’s gas in the tank. And that’s how the Volt operates on a long trip, same as the 14.


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This needs a little further explanation.

I use Hold Mode frequently when I am going to drive on the freeway for any distance except locally. (I also drive exclusively in Lo and Sport mode, when on the battery)

As soon as I hit the freeway I switch to Hold. The Main battery will hold as instructed. But if you do something, like climbing a hill and showing off, you can deplete the main battery, leaving the hold point where it was before, but reducing the amount of juice indicated.

Then if you continue to drive, without stopping and/or turning off the car, the ICE will recharge the battery back to the hold line, regardless of where it was, like, for example 50 miles of juice available..

This technique enables me to go a long distances on the freeway and have plenty of juice to drive around the city and make the Enviros happy, (and me too). It also saves juice when driving in the SF Bay Area during commute periods, driving stop-and-go at 5mph. I've used this technique on 8 hour trips of mountain ranges. I have the juice available when I need it.

I am comfortable with the knowledge that the car on the ICE at freeway speeds is more efficient than when using the battery exclusively. The reverse is also true.
 

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Put another way: In Mountain Mode the ICE will recharge the battery up to 40% if it is below this. This is used to aid you in uphill stretches in the mountains (hence the name). The percentage is less in Gen 2 which has a more dense battery so I don't know how much different this is in actuality, they may have decided you don't need as much energy to do the job.

In normal mode (EV) when the battery is "depleted" there is a buffer that is used to aid the motor up hills and that is regened when used on the next level road, downhill, slowing for a light and/or braking. You can see this grow and diminish on centre display when the leaf button is pushed, by a bar in the battery pack icon. It also tells you in English whether engine, engine and battery or just battery is used or it is being regened on the display as it is hard to tell except for the subtle raise in rpm or temporary shutting down of the engine. The car uses this buffer to start up and once you are going the ICE will be switched back on to power the car and recharge the buffer.

Although I haven't checked it I imagine the same thing is happening in Hold Mode (2013 and up) except the battery is kept at a particular level where it was switched rather than at the bottom.
 

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In so far as I can model it, Mountain Mode on a gen 2 acts the same as Hold Mode, except the hold position is fixed at that ~9 or 10 miles of ev range level.

In my own experience, my 2018 will recharge in Hold Mode to the point it started at, but on its own terms. You can see this especially if you turn on Hold mode just before getting on the highway in icy weather. It seems to barely bother with actually using ICE for propulsion until the ICE gets warmed up. Instead it drains EV range, even dropping a bar below the Hold position, then the bar comes back after driving for awhile, particularly once I get the cruise locked in at full speed. I suspect it is keeping its promise, but using the battery to get that 0 to 70mph acceleration onto highway until the ICE is ready to do its thing then recharging it back to where it was supposed to be.

I've yet to see what my gen2 will do if I drain to charge-sustaining mode then put it into mountain.
But I fail to see the point of people trying to "recharge" the battery back from gas. It is less efficient than just using the ICE directly when you've got no useful battery capacity left.
 

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But I fail to see the point of people trying to "recharge" the battery back from gas. It is less efficient than just using the ICE directly when you've got no useful battery capacity left.
When you are blasting down mountain at 75mph, you will probably note that the ICE will devote substantially all its effort to recharging back up to the Mountain Mode or Hold, depending on your choice of mode. This points out why I think the hold is better because Hold will restore all of your lost juice, whereas, Mountain Mode s limited to the fixed hold point.

You can watch it do its thing by switching the infotainment display to Energy >> Flow.
 

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I have a Gen 1 (2014) Volt and love it.

I've read two articles recently on the ending of Volt production in 2019.

In each article, they say that when electric range is depleted - the internal combustion engine starts and recharges the propulsion battery.

I am having trouble with that. In my Gen 1, the only way to recharge the propulsion battery is 'regen' while slowing and braking, and then plugging it in at home.

So: Does the Gen 2 Volt actually recharge the propulsion battery? If so, there'd be no need to plug it in. Right?

It is more accurate to say the engine maintains sufficient charge for continued operation. Mountain mode will provide a partial recharge, but will not completely recharge the battery. Gen 2 is no different in this regard.
 

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I have a Gen 1 (2014) Volt and love it.

I've read two articles recently on the ending of Volt production in 2019.

In each article, they say that when electric range is depleted - the internal combustion engine starts and recharges the propulsion battery.

I am having trouble with that. In my Gen 1, the only way to recharge the propulsion battery is 'regen' while slowing and braking, and then plugging it in at home.

So: Does the Gen 2 Volt actually recharge the propulsion battery? If so, there'd be no need to plug it in. Right?
The engine acts as a generator and most definitely charges the battery and then the battery powers the wheels. Why would the engine even be needed if it didn't do that??
 

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This points out why I think the hold is better because Hold will restore all of your lost juice, whereas, Mountain Mode s limited to the fixed hold point.

You can watch it do its thing by switching the infotainment display to Energy >> Flow.
Hold essentially does the same thing as mountain mode. Only difference is you set the hold point to the level where hold mode is turned on. It still won't fully recharge the battery unless you switch to hold with a full battery. But then you won't have much headroom for regenerative braking.
 

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The engine acts as a generator and most definitely charges the battery and then the battery powers the wheels. Why would the engine even be needed if it didn't do that??
It doesn't charge the battery in the sense that the engine will fully charge a depleted battery. The general purpose of the engine is to provide additional range beyond what a fully charged battery would. On a road trip you can stop and refuel for about another 300 miles of range in 5-10 minute instead of the 30+ minutes even the faster EV chargers can currently manage.
 

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In Hold mode, the Volt ICE can add one or two green pips above the hold point and then, shut off to use them back up.
 

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In my own experience, my 2018 will recharge in Hold Mode to the point it started at, but on its own terms.
Yes, the Gen 2 "hold" has a weaker grip than Gen 1. Gen 2 definitely "borrows" more from the battery and won't prioritize bringing the battery back to the SOC hold setpoint. From my experience, once you get above 65 MPH, forget it. I found the "sweet spot" between 45-55 MPH for it to keep a tighter hold--if that's important.

On the other hand, the deep draw into the battery buffer allows me to go to "zero" EV range when I'm 3 miles from home in the city traffic--and STILL often make it home without the ICE firing up. (It then reads some crazy MPG like 96 MPG on gas!).

The downside of course is that you can lose a bar of EV range and if you're counting on those couple of EV miles you might get disappointed and find your kWh used for the day around 13.6-13.8.
 

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The engine acts as a generator and most definitely charges the battery and then the battery powers the wheels. Why would the engine even be needed if it didn't do that??
In Extended Range Mode, the Volt’s motor operates on gas-generated electricity, not battery power. In effect, when the car "transitions from battery to gas," the motor’s fuel source moves from the battery to the generator output. As the Gen 2 reviews put it, the ICE powers MGA, and "MGA’s electric output is sent down to MGB to power the wheels."

The battery, however, remains a source of "borrowable power" when needed to maintain performance. Switching to Mountain Mode increases the "switch to gas" state of charge to provide a larger buffer of "borrowable" power when high power demand driving conditions are anticipated (such as when driving up mountains). Mountain Mode has a "feature" that will recharge the battery to the MM-maintained level (~4 bars for a Gen 1, ~2 bars for a Gen 2) if your battery is already below that level (allows you to create a larger buffer without stopping to recharge via wall plug). Hold Mode similarly allows the driver to set the "borrowable battery buffer" state of charge above the normal "fully depleted battery buffer" state of charge.

Any power borrowed "as needed" will be recharged by the generator when demand is reduced, and thus the generator does "recharge the traction battery" during normal operations. The generator is not used to fully recharge the battery because the concept of the Volt is to minimize the use of gas.

Keep in mind the engine’s primary function in a Gen 1 Volt is to crank the generator. The car is capable of full performance using only the large motor, and in Extended Range Mode, as long as the car remains in one-motor operation (e.g., in stop and go driving, or when accelerating to merge onto the freeway), the Gen 1 Volt is an all-electric car running entirely on gas-generated electricity. GM calls this "electric-like" driving. Gen 2 Volt Extended Range Mode operation is a much different animal, capable of propelling the vehicle under certain conditions using only the engine, with no propulsion torque supplied by the motors.
 

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Coming from a Gen1 and literally having the Gen2 for only a few days, it's much more complicated it appears than Gen1.

Nevertheless, I think the answers to the OP's question are going off on a tangent although I will admit to some confusion on what he/she's exactly asking.
 

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I think the bottom line is don't take too literally what a couple of reporters who are not experts on the Volt may have written about how it works. They researched that article for a few hours and then wrote whatever. They have probably never been any closer to a Volt than passing one in traffic. As a Volt owner, you know much more about its operation.
 

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From the diagrams and descriptions I've read, GM realized that having the ICE directly drive the car is more efficient than having the ICE create electricity which then drives the car. This is simple mechanical Thermodynamics - each conversion of energy loses some energy in the form heat. As for Mountain Mode, the Gen 2 Volt doesn't need this mode. I proved this driving over three of highest paved passes in North America this fall leaf peeping in Colorado's high country. My results of that day trip are at https://gm-volt.com/forum/showthread.php?326679-Mountain-Mode-not-needed-(Gen-2).

For the comment about Gen 2 not honoring Hold/Mountain Mode settings at high speed I can also attest to this. The first time I drove to New Hampshire I put my Volt in Mountain Mode and drove across Kansas at or just above the posted 75 MPH speed limit. When I arrived in Topeka there was zero battery SOC left. Once I dropped to 70 or below the car recharged the battery to about 5-7 miles of EV range. It appears the Gen 2 will only recharge the battery at high speeds to maintain the battery at 0% SOC. Going below 0% SOC is a battery life issue, but not recharging back to the Mountain Mode or Hold Set point is a recognition of the excessive energy cost required to do this. On my next trip (Total Solar Eclipse in Nebraska), I left the car in Normal and had no problems even at 90+ MPH flow of traffic on the climb back up to Denver on I-76. Since then I have left the car in Normal and let the on-board computers figure it out and have never seen a Propulsion Reduced message as a result not having available battery power.
 

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In general terms, the goal of the Gen 1 Voltec in hybrid mode was to use the ICE to generate just enough power to operate the traction motor. The ICE is operated in a number of fixed speeds for maximum efficiency. So sometimes it generates a bit more power than needed, sometimes a bit less. The battery acts as a buffer to absorb excess power of supply power of the ICE generated power isn't enough.

The goal of the Gen 2 Voltec in hybrid mode is quite different as ICE power is used to directly drive the wheels. Torque from the ICE is mechanically connected to the wheel along with electrically generated torque.

The takeaway is the main purpose of the ICE in Gen 1 or Gen 2 is not to charge the battery, but to drive the wheels, either by driving a generator to power the traction motor in Gen 1, or via a direct mechanical path in Gen 2.The

An excellent description is given in this post https://gm-volt.com/2015/02/20/gen-2-volt-transmission-operating-modes-explained/
 

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This all settles into a basic answer, however: No. The gen2 won't really try to recharge the battery pack when it is depleted unless you put into Mountain Mode, and then it doesn't always try.

On a more technical note, I think gen2 does the same thing, !arry4pyro. Excess power from ICE will end up in battery, particularly in CS2 mode is listed as liking to operate at fixed RPMs. CS3 is less clear, but the engineer "art" shows it possible to send some kind of energy back into battery in CS3 mode.
 

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I know that G2 Volts will charge the battery when the hood is open ( contrary to the operating manual), I have done this as an experiment. Often wondered if it was possible to add a switch to simulate hood open to the computer so that the gas engine would charge the main battery above the hold mark. I know this is inefficient but there are times when it’s nice to arrive at a destination with a full battery. I figure the engine would recharge the battery at opportune times when heavy demand is not on the engine.
 
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