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Discussion Starter · #1 ·
On my return commute home, I have to climb a very steep hill that is about a mile long (with about 4-5 stop signs, before I get to the highway. I don't do hard accelerations. First, I left the car on 'normal' mode, and it sucked up the battery (used probably 6-7miles). I've set the car to mountain and it didn't seem to do much in terms of conserving battery. If I set it to 'hold' it did a good job of conserving battery and from the dash display, and I had enough battery for the drive home.

If I don't use 'hold', I don't have enough battery to make it home on battery. From the 'post trip report' display, it uses about 0.1gal from climbing the steep hill.

Is there a more efficient way of doing this?
 

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On my return commute home, I have to climb a very steep hill that is about a mile long (with about 4-5 stop signs, before I get to the highway. I don't do hard accelerations. First, I left the car on 'normal' mode, and it sucked up the battery (used probably 6-7miles). I've set the car to mountain and it didn't seem to do much in terms of conserving battery. If I set it to 'hold' it did a good job of conserving battery and from the dash display, and I had enough battery for the drive home.

If I don't use 'hold', I don't have enough battery to make it home on battery. From the 'post trip report' display, it uses about 0.1gal from climbing the steep hill.

Is there a more efficient way of doing this?
Mountain mode is rarely needed with the Gen II Volt. Mountain mode is designed to ensure you have enough battery reserve so that the electric motor(s) can assist the gas engine if needed when accelerating as when passing another vehicle on a long ascent. Unlike the Gen I Volt, the Gen II Voltec system's 1.5L gas engine has sufficient power for almost any situation. If you engage Mountain mode when the Volt's battery is depleted the gas engine will start, run for about 15 minutes if you let it, and build up a 15 - 20 % charge in the battery (2 bars on the battery meter.) If you already have more than 2 bars indicated battery reserve then the gas engine will not immediately start.

As your commute is at the outer limit of your battery range, see if you can find a place to plug in close to where you work. Even 30 minutes to 1 hour could make the difference between completing the trip on battery or using some gas.

I sometimes engage Hold mode for perhaps 5-7 miles when driving on the highway when the trip I am taking is at the outer edge of my estimated battery range. (I observe the engine coolant temperature while in Hold mode and wait until the temperature rises to 180F or higher before resuming Normal mode.) This ensures I will have enough battery charge for the return trip. If I only use the gas engine for 1-3 miles the engine would not be sufficiently warmed up to drive out any moisture from the engine. This typically consumes between 13 and 21 ounces of fuel. For comparison, this is approximately the amount of liquid in a 12 ounce can of your favorite beverage up to a Starbucks Venti (if you will.) I don't mind using a little bit of gas as this is what the Volt was designed to do. I have tried to push the Volt's EV range to the limit and still arrive home on battery. I find I get distracted by my remaining battery range if I misjudge my battery usage as I really don't want the gas engine to start up when I am just 1 mile from home. I prefer to arrive home with 1 bar of battery charge remaining than have range anxiety for the last few miles of the trip home.
 

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On my return commute home, I have to climb a very steep hill that is about a mile long (with about 4-5 stop signs, before I get to the highway. I don't do hard accelerations. First, I left the car on 'normal' mode, and it sucked up the battery (used probably 6-7miles). I've set the car to mountain and it didn't seem to do much in terms of conserving battery. If I set it to 'hold' it did a good job of conserving battery and from the dash display, and I had enough battery for the drive home.

If I don't use 'hold', I don't have enough battery to make it home on battery. From the 'post trip report' display, it uses about 0.1gal from climbing the steep hill.

Is there a more efficient way of doing this?
Mountain Mode doesn't do anything to "conserve" battery. It recharges a larger buffer so that there's ADDITIONAL power available for hill climbing in case the gas generator can't keep up with the demand of going up a long rise at speed. Consequently, you need to turn it on BEFORE you get to the slope, and if you've got more power than it would recharge to already anyway, all it does is revise the remaining electric range figures for what it's holding in reserve.

So if your goal is to use the electricity later in the drive, Hold mode is what you want. You can turn that on at any point, and the generator will do what it needs to do to make sure that when you turn Hold mode off, you'll be as close to the same state of charge as when you turned it on as is practical. It's still possible to use up some charge in Hold mode (see the above thing about "uphill at speed") and turn it off before that charge has been recovered.
 

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Discussion Starter · #4 ·
Great advice on the initial steep hill. Follow-up question:

Along the highway, there's a 1-2mi lower gradient hill, is it better to put the car into HOLD here and run the ICE for 5minutes or to let the battery deplete and run on ICE for the last 5 minutes of the drive?

Just trying to figure out if 5min of HOLD is more less efficient then running purely on ICE after I get off the highway. In both case, I'm running ICE for about 5minutes.

I realize I'm nitpicking, but I'm just trying to get a good understanding of this powertrain.

(Btw: I noticed on Friday morning that the estimated battery range was in the 60s when I started the car (full charge overnight). Thought it would only display up to 53. I'm guessing that it bases that number off previous full charge drives.
 

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Great advice on the initial steep hill. Follow-up question:

Along the highway, there's a 1-2mi lower gradient hill, is it better to put the car into HOLD here and run the ICE for 5minutes or to let the battery deplete and run on ICE for the last 5 minutes of the drive?

Just trying to figure out if 5min of HOLD is more less efficient then running purely on ICE after I get off the highway. In both case, I'm running ICE for about 5minutes.

I realize I'm nitpicking, but I'm just trying to get a good understanding of this powertrain.

(Btw: I noticed on Friday morning that the estimated battery range was in the 60s when I started the car (full charge overnight). Thought it would only display up to 53. I'm guessing that it bases that number off previous full charge drives.
It is really up to you, Hold mode gives you the option of deciding when to use gas and when to use the battery. In the summer, if you park in a garage, then arriving home without a hot engine is an advantage. If you want to use the Volt as it was designed, use all of the battery before switching to gas. Let the Volt run on the battery and then it will automatically switch to gas to complete the trip.

Driving at speeds above 55 mph consumes more battery charge than driving at lower speeds and also uses more gas, take your pick. Local street driving, at speeds under 30 mph, is most efficient for EV driving but not always practical. By doing so your estimated Volt's EV range will climb into the mid to upper 60s or low 70s and stay there until the temperature falls below 65F or until you start driving at faster speeds or drive more of your miles on the highway.

To maximize efficiency:

1) Slow down
2) Inflate your Volt's tires 2 -3 lbs above the rated 36 PSI
3) Limit your use of electric heat and to a much lesser extent limit the use of AC
4) Don't carry any unnecessary weight in the vehicle. Keep the gas tank between 1/3rd and 1/2 full if you don't regularly use gas.
5) Keep the exterior of the car clean, it will slip through the air more easily

Also:

Coasting in Neutral to a traffic signal that is red (not recommended or practical when driving in traffic) is more efficient than taking your foot off of the accelerator when driving in D. Driving is D (a modest amount of regen is applied when you take your foot off of the accelerator) is theoretically more efficient than driving in L (more regen is applied when you take your foot off of the accelerator) because driving in D is closer to coasting but some report slightly better efficiency when driving in L.
 

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Discussion Starter · #6 ·
One thing that's taken some getting used to is slowing down via the regen paddle. I wish it was more analog or enabled you to control how much regen you're applying rather than an "all or none". Sometimes I wonder if it's too aggressive when having passengers in the car, i'd rather it be a little weaker but run it longer (say pulling up to a stop light).
 

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One thing that's taken some getting used to is slowing down via the regen paddle. I wish it was more analog or enabled you to control how much regen you're applying rather than an "all or none". Sometimes I wonder if it's too aggressive when having passengers in the car, i'd rather it be a little weaker but run it longer (say pulling up to a stop light).
The control you seek is in the brake pedal since the Volt provides true blended braking. Until the level of regen resulting from pressing the brake pedal exceeds the Volt's maximum regen level for the current braking event the friction brakes are not applied or only lightly applied.

I wish the regen paddle was more aggressive, it never seems to provide as much regen as I want. It took me a long time (almost a year) of driving my Volt to become comfortable with driving in L mode (much longer than becoming comfortable using the regen paddle.) Now I prefer driving in L for local stop and go driving. I still use D on the highway. My Volt has ACC so I frequently use the ACC in combination with L for local driving as well as on the highway.
 

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Now I prefer driving in L for local stop and go driving. I still use D on the highway. My Volt has ACC so I frequently use the ACC in combination with L for local driving as well as on the highway.(jcanoe-senior member).
Despite more regen decelerating in L,would not accelerating in L require more power than D?Perhaps reason Manual indicates D is best for efficiency?
Don-17 Volt LT
 

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Now I prefer driving in L for local stop and go driving. I still use D on the highway. My Volt has ACC so I frequently use the ACC in combination with L for local driving as well as on the highway.(jcanoe-senior member).
Despite more regen decelerating in L,would not accelerating in L require more power than D?Perhaps reason Manual indicates D is best for efficiency?
Don-17 Volt LT
L and D are not gears like they are in a traditional vehicle. Accelerating in L is exactly the same as in D, with the only difference when you fully iift the accelerator. L will give you more regen. If you are trying for fuel efficiency, stay in D, use the brake pedal for variable regen, and coast like the dickens. if you want a spirited ride then L can be fun for the driver, not so much for the passengers about to throw up with the herky jerkiness. It's all software to simulate L. The only real use for L is to help slow you down hills just like in an ICE car. Lots of people try to maximize their regen thinking that is most efficient, but in actuality, minimizing regen and maximizing momentum usually yields better EV range results.
 

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Now I prefer driving in L for local stop and go driving. I still use D on the highway. My Volt has ACC so I frequently use the ACC in combination with L for local driving as well as on the highway.(jcanoe-senior member).
Despite more regen decelerating in L,would not accelerating in L require more power than D?Perhaps reason Manual indicates D is best for efficiency?
Don-17 Volt LT
When accelerating, L and D are identical.

Best efficiency when slowing down is much like driving on snow. You want to anticipate the road ahead and drive such that you can gradually slow down by coasting. (E.g., in the Volt, try to keep the power meter at 0.5 kw). It is easier to do this in D than L. Otherwise regen is great because the kinetic energy is converted back into electricity at some percentage (like 80%) rather than being dissipated as heat in friction brakes. Like others, I typically drive in L around town and in traffic, and D on the open road.
 

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Neither. Just run it out of battery and use gas. Messing with MM and HM will generally result in less efficient operation than just letting the car figure it out.
 

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Now I prefer driving in L for local stop and go driving. I still use D on the highway. My Volt has ACC so I frequently use the ACC in combination with L for local driving as well as on the highway.(jcanoe-senior member).
Despite more regen decelerating in L,would not accelerating in L require more power than D?Perhaps reason Manual indicates D is best for efficiency?
Don-17 Volt LT
As others on this thread have stated, acceleration in the Volt is identical in either D or L mode. Only the amount of regen that is being applied by D and L differs. I wish GM would change the L designation to something more representative of this driving mode such as M for Max Regen. D could be changed to N for Normal but N is already universally used for Neutral. Oh well.
 

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OP, if you have a downhill stretch at speed put your car into hold mode at the start of this stretch. The gas engine will come on and have very little to do, resulting in the best gas MPG. The Volt implements Deceleration Fuel Cut-Off DFCO when running on gas going downhill. This will result in almost no gas (just the ICE startup) used while running on gas to save your battery.
 

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OP, if you have a downhill stretch at speed put your car into hold mode at the start of this stretch. The gas engine will come on and have very little to do, resulting in the best gas MPG. The Volt implements Deceleration Fuel Cut-Off DFCO when running on gas going downhill. This will result in almost no gas (just the ICE startup) used while running on gas to save your battery.
In this situation, even though you have selected Hold mode the Volt will quickly determine that the gas engine is not needed, as when you are stopped at a traffic signal, and shut off the gas engine as long as the amount of energy recovered while descending is sufficient to maintain your speed, any excess energy that is recovered will go into the battery. Climbing a mountain and then stopping to fully recharge the Volt would be less efficient than starting your descent with no more than 50% battery charge so that you could let the Volt's regen recover the maximum amount of energy when descending the mountain. Once the battery is at 100% charge the Volt dumps any excess energy captured by regen as waste heat else the Volt must suspend regen.
 

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In this situation, even though you have selected Hold mode the Volt will quickly determine that the gas engine is not needed, as when you are stopped at a traffic signal, and shut off the gas engine as long as the amount of energy recovered while descending is sufficient to maintain your speed, any excess energy that is recovered will go into the battery.
True. I had a similar situation back in June - I only had about 30 miles EV available and had a 50 mile round trip for an Eagle Scout Court of Honor. I got home with 97 MPG gas and 1 EV mile left. I took advantage of the terrain and drove EV uphill and Hold or Mountain Mode on the downhills (Hold on the way out and MM on the way back).
 

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Be respectful of drivers behind you when trying for max energy conservation. Not worth creating ill will or road rage just to save 3 cents worth of electricity. Go with the flow.
 

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It's hard to imagine a Volt owner still having range anxiety. Don't sweat it, you're only going to burn a little gas no matter how you juggle the modes. If your journey can almost make it both ways on a charge but you have to run the ICE for a bit, you're still way ahead.
 

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Great advice on the initial steep hill. Follow-up question:

Along the highway, there's a 1-2mi lower gradient hill, is it better to put the car into HOLD here and run the ICE for 5minutes or to let the battery deplete and run on ICE for the last 5 minutes of the drive?

Just trying to figure out if 5min of HOLD is more less efficient then running purely on ICE after I get off the highway. In both case, I'm running ICE for about 5minutes.

I realize I'm nitpicking, but I'm just trying to get a good understanding of this powertrain.

(Btw: I noticed on Friday morning that the estimated battery range was in the 60s when I started the car (full charge overnight). Thought it would only display up to 53. I'm guessing that it bases that number off previous full charge drives.
It's both more complicated and simpler than that.

Let's start with Charge Sustain (cs) mode. That's what the car does when it's "out of battery". It's not really out but it's down around (I think) 20% charged. There's a small window there that we can call csLow and csHigh. The difference between those is about (from behavior and for Gen 1, since I don't have a Gen 2) 0.5 kwh. So 3-4% of the battery's real capacity. When the charge gets below csLow, the ICE turns on, and does what it's gonna do until the battery is charged up to csHigh, at which the ICE turns off. The generator running off the ICE can fill that in about two minutes if nothing else is going on, but there's almost always something going. There's power going to lights and computers, and motors pushing the car along unless you're stopped someplace. If the load is low enough, it'll catch up and the ICE shuts off and you're driving along in a "phantom EV mode" until you use up from csHigh to csLow. If you're going down a hill at the time, that might several miles. If you're going up or driving fast, it won't be long at all.

Now, as part of the "it's more complicated", the ICE running isn't ALWAY generating a lot of power. The first 40 seconds or so, it's warming up and making sure the fluids are all moving properly, so it doesn't generate more than about 6kw. (It's also drinking a comparative lot of fuel at this point because fuel = heat and we want to get up to operating temp as soon as possible.) After that, it'll generate up to about 50kw, plus power splitting to help drive the wheels if conditions are right. How much power it generates is determined by the rate that power is being used, and how far below csLow things have gotten in the time between "Turn on ICE" and the "warmed up and ready" state. So the most typical pattern you'll seen when tooling down the highway and you "run out" of battery is the engine comes on, thrums along quietly for a while, then revves up (maybe a lot) for a couple of minutes, then settles down to a rate someplace between the two, varying by things like hills, wind, drafts behind other traffic, and all mostly delayed by anywhere between 5-15 seconds from what people expect, because the ICE is actually chasing the power drain between those two csLow and csHigh points instead of reacting to the road conditions as they are Right Then. And this includes turning off for a long while if you're stopped at a light, or going down a hill steep enough that most of the power you need to maintain speed comes from the slope itself.

And that's basically all the complicated. Here's where it gets simple: Hold mode just temporarily sets a new (I think) hmHigh right at whatever the current sate of the battery is and a new hmLow at the appropriate window below the hmHigh. Mountain Mode sets a new mmHigh at a Generation-specific point and a corresponding mmLow. Gen 1 it's about 40% on the meter, and 20% on the Gen 2. And then the ICE generator does what it needs to get there, whether that's use up the power that's above mmHigh driving or roaring through a quart or two of gas to get the battery up from "empty". (Gen 2 gets less because the gas engine is little more powerful than the one in Gen 1, AND it can power split and supply motive force under more conditions, so the overall need for pure electric power is less. Gen 1 can't power split at low speeds so it depends on its reserve more.)
 

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One thing that's taken some getting used to is slowing down via the regen paddle. I wish it was more analog or enabled you to control how much regen you're applying rather than an "all or none". Sometimes I wonder if it's too aggressive when having passengers in the car, i'd rather it be a little weaker but run it longer (say pulling up to a stop light).
You're not alone in that thought. That's why the wide pedal still does regen exactly like it does in the Gen 1: variable regen and a seamless transition to friction brakes when the car is slow enough that regen starts fading to nothing.
 
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