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Discussion Starter · #1 ·
Sorry if wrong place BUT... I have a question. As most new Volt drivers are... I'm becoming obsessed with the best mileage. I will be about 75/25 electric/"fuel" miles. What is the optimal speed to "drive gas"? I'm sure highway is probably the most efficient time to use hold correct? Is there an optimal speed? 60, 65, 97, 70? I'm sure flat vs hills, slow grades vs steep all make a difference I'm just currious. Btw I've got about 70miles on gas and I'm at 40.2 :) around 215ish overall mpg with somewhere around 350 miles +-20.

Loving it btw :)
 

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Slower the highways speeds the better the efficiency but HVAC use and it very little acceleration to start chipping away at the range...On the instrument display, with the green ball, my WAG tells me if you push the accelerator more than 15% the ball is off the charts and you're now inefficient...
 

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The third graph in the post here provides some insight. Regardless of power source, efficiency drops at speeds above 55mph primarily due to air resistance.

http://gm-volt.com/forum/showthread.php?288713-Effect-of-Speed-and-Temperature-an-extrapolation-for-2017-Chevy-Volt

The Volt is most efficient between 20 and 36 mph. For overall best efficiency use EV mode for driving at all speeds until the battery charge is depleted (contrary to my example below) and then use gas. Hold mode can easily exceed the EPA mpg estimate of 42mpg combined. You want the gas engine to reach full operating temperature for best efficiency, monitor the engine coolant temperature and you will see it stabilize at between 185 and 205 F, then it has reached full operating temperature.

If you consider the cost of electricity in your area then at current gas prices EV mode and when using gas may be within 1 cent per mile of actual cost. The last time I calculated this in my area the cost was 4.5 cents per mile EV and 5.5 cents per mile gas.

I usually try and hold my highway speed to no more than 62 - 65 mph (EV) and 65 - 70 mph (gas).

On a recent trip I traveled ~70 miles (60 miles highway and the rest secondary roads): 55 miles EV and 15 miles using gas. The Volt displayed 54.7 mpg (gas) but I am sure this included additional miles due to regeneration. I used Hold mode for part of the way (both going and on the return trip) as I like to arrive home on battery power. My Volt still had approx. 4 miles of EV range when I arrived home so I could have traveled a bit further on battery than I did. The air temperature was in the 70s. The Volt showed a combined MPG of 250+

The unused battery capacity (approx 1 kwh) was not wasted, the Volt recharged in 4 hours instead of 4.5 hours it would have taken if the battery had been fully depleted. I estimate I used an additional 9 oz. of gas to travel the extra 4 miles on gas instead of battery.
 

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The most efficient speed to drive the first generation Volt on gas was 36 mph - just over the threshold where the engine was mechanically linked to the wheels.

The second generation Volt is always linked, though, so I'm thinking the most efficient speed on gas is likely the same as the most efficient speed on electricity - somewhere in the 20 mph range.

Of course, that's not really a practical way to drive in the US today. So the general rule is as slow as you're comfortable going, with as mild acceleration and deceleration as you can safely manage.

Or, you know, ignore the gauges and drive it like you stole it - and realize you're still getting better economy on both gas and electric than 90+% of the cars on the road with you. :p
 

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I would use hold above 60 mph only if you want to reserve EV miles for your destination.

Here is the thing, at speeds above around 60 mph drag will be large and allowing the internal combustion engine to run in parallel will use less total energy than only using the electrical motors (depending on fuel costs it might still be cheaper to run EV only). Determining that exact point depends on a lot of parameters and might not be practical, but given that the genset is running, the car can use parallel mode at anything above 36 mph or so depending on torque requirements.

Again, if you want to reserve EV power for your destination, use hold, otherwise I wouldn't worry about it.
 

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Sorry if wrong place BUT... I have a question. As most new Volt drivers are... I'm becoming obsessed with the best mileage. I will be about 75/25 electric/"fuel" miles. What is the optimal speed to "drive gas"? I'm sure highway is probably the most efficient time to use hold correct? Is there an optimal speed? 60, 65, 97, 70? I'm sure flat vs hills, slow grades vs steep all make a difference I'm just currious. Btw I've got about 70miles on gas and I'm at 40.2 :) around 215ish overall mpg with somewhere around 350 miles +-20.

Loving it btw :)
Why don't you try a few scenarios out for yourself and see which is best? No one can answer what's best for you as your terrain, miles you drive, etc are all relative your conditions.

I personally have not driven on any fuel miles except one time where I ran out of EV miles 2 miles away from home. I've also had two EMM sessions.

If it wasn't for the stupid FMM every year that I've not had yet, I'd have anticipated not having any fuel miles at all as my 75 miles of EV range every day is more than enough for me.

I average around 60-65 MPH on the highway BTW. I'm "Voltser" on Voltstats.

There is absolutely no reason to use hold mode or mountain mode if you know you'll have enough miles to drive back and forth on EV alone. No matter what regime you are in, EV mode is always more efficient. Using the engine is only a "must" in my book.
 

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Discussion Starter · #7 ·
Thanks for all the responses everyone!

My scenario was I was about 5 miles short of EV and I couldn't decide if it would be better to use the gas on the highway and EV on the backroads.

I also wondered if using mountain mode was a good idea when I was out of EV, for say 10 miles on the highway or backroads, to build up slightly for the last couple miles from the off ramp to my house.

Sent from my SM-G900V using Tapatalk
 

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Discussion Starter · #8 ·
Btw in looking at the charts and such is cool. Any way to make my own, like download my car lol

Sent from my SM-G900V using Tapatalk
 

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I used to drive it like a grandpa trying to eek out every mile, now I drive like Jeff Gordon taking on any and all pony cars and ricer boys. It's much more fun to drive it like a jackrabbit, ev miles be damned. It took me two years to get there... stop agonizing yourself and just break the cycle now. Otherwise you might become an Ari_C at 20+K miles with no fuel at all (probably more by now).
 

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Thanks for all the responses everyone!

My scenario was I was about 5 miles short of EV and I couldn't decide if it would be better to use the gas on the highway and EV on the backroads.

I also wondered if using mountain mode was a good idea when I was out of EV, for say 10 miles on the highway or backroads, to build up slightly for the last couple miles from the off ramp to my house.

Sent from my SM-G900V using Tapatalk
Ah. That's a somewhat different question. The general consensus is to use the ICE for part of the freeway portion. It's likely a little better for efficiency without the start/stop cycles of the lower speed parts, but mostly it's a lot more pleasant - at 60 you'll only know the engine is on from the instruments, but in stop and go you'll feel and hear the engine.
 

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Thanks for all the responses everyone!

My scenario was I was about 5 miles short of EV and I couldn't decide if it would be better to use the gas on the highway and EV on the backroads.

I also wondered if using mountain mode was a good idea when I was out of EV, for say 10 miles on the highway or backroads, to build up slightly for the last couple miles from the off ramp to my house.

Sent from my SM-G900V using Tapatalk
You're overthinking it. For a 5 mile stretch any work you do is only going to save a few dozen feet or so. Don't use mountain mode. There are losses in the conversion of motion to electricity to storage in the battery to the electric motor. In hold mode, it goes from motion to electricity to the electric motor.

Whatever you do, don't put it into a mode and forget, thus pulling into the driveway with lots of battery miles. I've done that enough times that I've decided it's best to just drive until you run out of juice and let the car switch to Dino juice. In the winter, however, the best tactic is to precondition, then start the car in hold mode with the climate control off to warm the ice, and partway through turn on the heat. With my highway commute, I hit the highway, then city streets for about 7 miles, I'evve arrive in city traffic with 30+ miles on the guessometer, switch from hold to normal, and would drive the rest of the way withoutmlosing any miles on the guessometer. The winter tactics change as the range will drop to around half.
 

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Thanks for all the responses everyone!

My scenario was I was about 5 miles short of EV and I couldn't decide if it would be better to use the gas on the highway and EV on the backroads.

I also wondered if using mountain mode was a good idea when I was out of EV, for say 10 miles on the highway or backroads, to build up slightly for the last couple miles from the off ramp to my house.

Sent from my SM-G900V using Tapatalk
In the 2016 and 2017 Volt Mountain mode will build up approx. 2 bars (20%) of battery charge. Use it if you have exhausted the battery, at least 20 minutes before you plan to start a long ascent. Mountain mode will use more gas, perhaps 20% more, than the gas engine would otherwise use while it builds up a charge. It is more efficient to let the Volt automatically switch from EV to charge sustaining mode (gas engine) as the battery becomes depleted or manually select Hold mode while you still have some remaining battery range that you prefer to save for later use.
 

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My scenario was I was about 5 miles short of EV and I couldn't decide if it would be better to use the gas on the highway and EV on the backroads.
Your manual may have had this information:

Electric range is maximized at 80 km/h (50 mph) and below. Higher speeds use more energy and can significantly reduce electric range.
So above 50 mph is the better time for using hold mode.

I also wondered if using mountain mode was a good idea when I was out of EV, for say 10 miles on the highway or backroads, to build up slightly for the last couple miles from the off ramp to my house.
It's a waste of gas if you're using hold mode anyway, and certainly not efficient. I've done it a few times it though when my battery was drained already.
 

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Whatever warm weather driving routine you settle on will be disrupted by winter temperatures. Battery range will drop an estimated 20% or so, that is without using the climate control system's electric heat.

If you have level II charging at home then you will want to precondition the Volt in the morning so it is warmed up when you leave. Use the electric seat heater and steering wheel heater (if equipped) as this uses very little energy. Use of Engine Heat Assist is a personal choice. This will start and cycle the gas engine on and off but it uses very little gas and effectively heats the cabin. By default Engine Heat Assist activates when the outside temperature drops below 35F. You can defer Engine Heat Assist until the outside temperature drops below 15F.
 

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Ah. That's a somewhat different question. The general consensus is to use the ICE for part of the freeway portion. It's likely a little better for efficiency without the start/stop cycles of the lower speed parts, but mostly it's a lot more pleasant - at 60 you'll only know the engine is on from the instruments, but in stop and go you'll feel and hear the engine.
I totally concur with Walter's logic. It's the exact logic I utilize.
 

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Last Saturday 135 mile round trip with our 2016 Volt. Returned home with 70 miles electric used the remainder on gas for 52+ mpg on just gas, Prius Territory,. Temp was 58-64, dry roads, speeds on Highway 101 from my Tillamook Oregon fishing trip and back ranged from 60 mph to 25-45mph when driving in small towns in city limits.
 

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I always accelerate to the speed limit quickly at every red light I'm at...


However, today I found myself driving conservatively back home after an 8 hour shift. Today's been really the only day i've been pretty mentally and physically tired. So I guess I drive slower when I'm tired... which is rare.... 21 mile commute home with 27 EV miles, half streets/half freeway and made it home with 5 EV miles remaining while using the AC the entire way. Usually I run out. Not bad.
 
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