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Discussion Starter · #1 · (Edited)
2013 Volt with 23,000mi
We've been having a serious cold snap (9 degrees F to 14 degrees F in the morning) so I've taken the numbers from my earlier cold weather driving, before the warm days we just had, and the recent numbers and calculated the averages.

This is "just driving" the Volt as though it were any other vehicle, not trying any efficiency or hyper-miler tricks. Keeping comfortable cabin temps (comfort mode) and just driving in "D" as I usually would. (note - this includes 10 min pre-conditioning and then allowing the charge to top off again)

The numbers got pretty consistent once the temps fall below about 26 degrees F

39mi each way

27.1mi on Electric (70% of trip)
9.7kWh used of 10.6kWh (91.5% of capacity)
2.79 MPKW (Miles per KW)

11.7mi on Gasoline (ERDTT running automatically at various points for 30% of trip)
0.36 Gallons used (32.5 MPG)
 

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You'll do much better starting out in "hold" mode in cold weather when you know you won't have enough battery range to make it. This will use "free" heat from the engine to warm things up first and drastically reduce the power used from the battery for heating as well as giving you better mpg's for the trip.
 

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Discussion Starter · #3 ·
You'll do much better starting out in "hold" mode in cold weather when you know you won't have enough battery range to make it. This will use "free" heat from the engine to warm things up first and drastically reduce the power used from the battery for heating as well as giving you better mpg's for the trip.
Thanks, I will try that down the line. I just wanted to establish an "auto-mode" baseline as it were so I could see what the Volt does when left to it's own devices.
 

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Yesterday my day started at -10F, preheat was engine assisted, and more than 50% of my morning drive distance was on ERDTT! Still managed 26 EV miles for the charge though.

Somehow it manages to pick the moment I crest a hill to start ERDTT, and the moment I'm about to climb one to stop.
 

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2013 Volt with 23,000mi
We've been having a serious cold snap (9 degrees F to 14 degrees F in the morning) so I've taken the numbers from my earlier cold weather driving, before the warm days we just had, and the recent numbers and calculated the averages.

This is "just driving" the Volt as though it were any other vehicle, not trying any efficiency or hyper-miler tricks. Keeping comfortable cabin temps (comfort mode) and just driving in "D" as I usually would.

The numbers got pretty consistent once the temps fall below about 26 degrees F

39mi each way

27.1mi on Electric (70% of trip)
9.7kWh used of 10.6kWh (91.5% of capacity)

11.7mi on Gasoline (ERDTT running automatically at various points for 30% of trip)
0.36 Gallons used (32.5 MPG)
FWIW, those are fairly typical temperatures around here, except this winter, and your numbers are close to what I get by just getting in and driving. (rough mental unit conversions only)

After the new wore off I stopped trying to find anything that worked better than the factory settings. I never could find a significant improvement over just using 'Eco' mode, setting the temp at 21 C., (25 in summer), and letting the car do the rest.

Of course 'your mileage may vary' and the Volt is fun to explore and experiment with, so keep at it and let us know if you find anything that works better for you.
 

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Chevy, Volt 2013, ~221,000K Miles.
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I was recently seeing some of these issues myself. There are two points that I find very interesting with me personally.
- I use hold summer and winter for the first 20 miles of my drive, right now with similar temperatures as the first post here I am getting 34mpg where in warmer (even about 35F) I get 41 on the same stretch of highway. This is without ECO mode at all, using just fan and engine temp and dry road (No water drag issues).
- I have heard that the gas changes in the winter time in the colder states and is less efficient. I have seen this in my other cars but usually the MPG variance is more like 2 than 5 but maybe it's just more sensitive engine.
- Love to hear any other thoughts!

2013 Base package.
 

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39mi each way

27.1mi on Electric (70% of trip)
9.7kWh used of 10.6kWh (91.5% of capacity)
My commute's similar, and in Colorado it's usually very cold in the morning and much warmer in the afternoon.

In the morning, I start in hold. Electric heat eats the battery, and I'm going to use gas anyway at some point. Use Hold to heat up the car and get it comfy (let the interior get warm as well, as in the dash, seats, everything).
After about 10-15 miles, put the car in Mountain Mode. Electric is less efficient in cold, so I save half the battery for the afternoon drive when it's warmer. Engine kicks on for the last 5 miles or so.

In the afternoon, the sun has warmed the car up and temps are warmer. I can usually either use Eco or Fan only for the trip home, and make it almost home with the battery reserve that Mountain Mode held.

Even so, MPG runs about 60, while in summer it ran about 80mpg.
 

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Discussion Starter · #8 · (Edited)
UPDATE: Results from Pre-heating wtih Hold mode.

2013 Volt with 23,000mi
We've been having a serious cold snap (9 degrees F to 14 degrees F in the morning) so I've taken the numbers from my earlier cold weather driving, before the warm days we just had, and the recent numbers and calculated the averages.

This is "just driving" the Volt as though it were any other vehicle, not trying any efficiency or hyper-miler tricks. Keeping comfortable cabin temps (comfort mode) and just driving in "D" as I usually would. (note - this includes 10 min pre-conditioning and then allowing the charge to top off again)

The numbers got pretty consistent once the temps fall below about 26 degrees F

39mi each way

27.1mi on Electric (70% of trip)
9.7kWh used of 10.6kWh (91.5% of capacity)
2.79 MPKW (Miles per KW)

11.7mi on Gasoline (ERDTT running automatically at various points for 30% of trip)
0.36 Gallons used (32.5 MPG)
The new numbers are in. Temps weren't quite as cold for a couple of days but the range still went from 11F to 33F
This represents PRE-CONDITIONING the vehicle for 10 minutes while still connected to the grid and then allowing it to "top-off" the charge and then driving in HOLD mode for the first 4 miles of my trip to heat everything up to max.
The only aspect that was changed was the 4 mile HOLD mode drive. All other elements (lights, heat settings, etc) remained the same.

39mi each way

30.9mi on Electric (79% of trip)
10.0kWh used of 10.6kWh (94.3% of capacity)
3.09 MPKW (Miles per KW)

4.0mi on HOLD (10% of the trip)
0.11 gal used (36 MPG)

5.0mi on Gasoline (ERDTT running automatically at various points for 12.8% of trip)
0.15 Gallons used (33 MPG)

0.26 Gallons used total (34.5 average MPG)

So according to these numbers Pre-conditioning the car and then driving the first four miles in HOLD gave me a pretty consistent 9% increase in Electric Only Range and MPKW efficency and a 27% decrease in Gasoline use over the course of 4 days (8 trips).
 

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Have a 2012 with 33K on the clicker. 2012s do not have the 'HOLD" button option. I drive in "D".

Today low to mid 40's while driving. Did manage to get 50.5 miles on electric (even I was surprised) - but I just used the seat warmer.

When the gas engine began to run, MPGs blew chunks compared to summer.

Used .53 gals to go 21 miles.... ~37.5 miles/gal. Actually not bad. Summer time would maybe have equated to 42-43 mpgs over same road. Should mention I drive just over posted speeds and keep the tires at 46 psi (warm).

What happened was for the first 15 miles I was getting the equivalent of 22-25/mpg. Speculation as to why: winter formula, an engine that needed to warm up, kharma, etc. made for some crappy MPG that evened out by the end of the trip. Was driving the same as I always do - gingerly.

Interestingly, the total miles estimated by the car computer that I would get on fuel left in the tank was 300 miles. By time I stopped at my house.56 gals later it was 298 miles.

For now, I attribute to cold air, cold engine, mid-Atlantic formula in gas as mandated by federal gov't. All speculation on my part, but I guess not out of the realm of likelihood.

Good thread....


I was recently seeing some of these issues myself. There are two points that I find very interesting with me personally.
- I use hold summer and winter for the first 20 miles of my drive, right now with similar temperatures as the first post here I am getting 34mpg where in warmer (even about 35F) I get 41 on the same stretch of highway. This is without ECO mode at all, using just fan and engine temp and dry road (No water drag issues).
- I have heard that the gas changes in the winter time in the colder states and is less efficient. I have seen this in my other cars but usually the MPG variance is more like 2 than 5 but maybe it's just more sensitive engine.
- Love to hear any other thoughts!

2013 Base package.
 

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When the gas engine began to run, MPGs blew chunks compared to summer.

Used .53 gals to go 21 miles.... ~37.5 miles/gal. Actually not bad. Summer time would maybe have equated to 42-43 mpgs over same road. Should mention I drive just over posted speeds and keep the tires at 46 psi (warm).

What happened was for the first 15 miles I was getting the equivalent of 22-25/mpg.
I find that the first dozen or so ICE miles are pretty crappy, even in summer (though Michigan summer is cool by Maryland standards). My other car has water, oil temperature, and oil temperature gauges; it shows that while water temps come up quickly, oil takes around 10 minutes longer both in winter and summer. Water conducts heat much better than oil, so the oil temperature simply can't rise as fast. Standard oil pumps are "constant-displacement", delivering a fixed number of liters/minute at a given rpm. Since cold oil is more viscous than warm, this means that the oil pressure for a given rpm is higher. Thus the resistance felt by the pump is greater and it sucks hp that would otherwise go into moving the vehicle. The Gen2 should be better in this regard because, IIRC, it has a variable-displacement oil pump (as well as a variable-flow electric water pump) which will reduce wasted energy, especially when starting cold.

Additionally, regardless of the outside temperature, the ECU injects extra fuel on startup to get the cat hot ASAP, since they don't work when cold. Older cars had the cat underneath the car, newer ones (Gen1) have them under the hood, and the newest (Gen2) have them as part of the exhaust manifold; each move reduces the enrichment time needed to heat up the cat.

Gen2 should be much kinder to mpg's during warmup, but in lieu of the technology improvements, Gen1 owners can maximize their mpg's by minimizing short-duration ICE running.
 

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You'll do much better starting out in "hold" mode in cold weather when you know you won't have enough battery range to make it. This will use "free" heat from the engine to warm things up first and drastically reduce the power used from the battery for heating as well as giving you better mpg's for the trip.
The new numbers are in. Temps weren't quite as cold for a couple of days but the range still went from 11F to 33F
This represents PRE-CONDITIONING the vehicle for 10 minutes while still connected to the grid and then allowing it to "top-off" the charge and then driving in HOLD mode for the first 4 miles of my trip to heat everything up to max.
The only aspect that was changed was the 4 mile HOLD mode drive. All other elements (lights, heat settings, etc) remained the same.

39mi each way

30.9mi on Electric (79% of trip)
10.0kWh used of 10.6kWh (94.3% of capacity)
3.09 MPKW (Miles per KW)

4.0mi on HOLD (10% of the trip)
0.11 gal used (36 MPG)

5.0mi on Gasoline (ERDTT running automatically at various points for 12.8% of trip)
0.15 Gallons used (33 MPG)

0.26 Gallons used total (34.5 average MPG)

So according to these numbers Pre-conditioning the car and then driving the first four miles in HOLD gave me a pretty consistent 9% increase in Electric Only Range and MPKW efficency and a 27% decrease in Gasoline use over the course of 4 days (8 trips).


Thanks for the idea and for the data to prove it.
 

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Ok so what kind of charge do you get when cold and is the car in a heated garage. Does the car show 39 miles for the electric mode? Later RJD
 

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Discussion Starter · #13 ·
Ok so what kind of charge do you get when cold and is the car in a heated garage. Does the car show 39 miles for the electric mode? Later RJD
I have an open car port. The location next to the house provides some weather shielding as well but generally it's within 2-3 degrees of outside temperature in the car port. That is part of why I love pre-conditioning so much!

The range on the "guess-o-meter" has run the gamut from 40 miles (on the one 71 degree day since I bought the Volt) down to the all time low of 27 miles on a single digit morning.

Keep in mind I bought the car in early December so I don't have a ton of data yet.
 

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I have an open car port. The location next to the house provides some weather shielding as well but generally it's within 2-3 degrees of outside temperature in the car port. That is part of why I love pre-conditioning so much!

The range on the "guess-o-meter" has run the gamut from 40 miles (on the one 71 degree day since I bought the Volt) down to the all time low of 27 miles on a single digit morning.

Keep in mind I bought the car in early December so I don't have a ton of data yet.
Thanks Dutch. The reason I was concerned is last winter it was much colder and I still got a 38 mile charge. So far our winter has been a lot milder and now only get 34 miles for a charge. My car also sets out side. BTW in the summer I will get a 46 mile charge . Later RJD
 

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I find that the first dozen or so ICE miles are pretty crappy, even in summer (though Michigan summer is cool by Maryland standards). My other car has water, oil temperature, and oil temperature gauges; it shows that while water temps come up quickly, oil takes around 10 minutes longer both in winter and summer. Water conducts heat much better than oil, so the oil temperature simply can't rise as fast. Standard oil pumps are "constant-displacement", delivering a fixed number of liters/minute at a given rpm. Since cold oil is more viscous than warm, this means that the oil pressure for a given rpm is higher. Thus the resistance felt by the pump is greater and it sucks hp that would otherwise go into moving the vehicle. The Gen2 should be better in this regard because, IIRC, it has a variable-displacement oil pump (as well as a variable-flow electric water pump) which will reduce wasted energy, especially when starting cold.

Additionally, regardless of the outside temperature, the ECU injects extra fuel on startup to get the cat hot ASAP, since they don't work when cold. Older cars had the cat underneath the car, newer ones (Gen1) have them under the hood, and the newest (Gen2) have them as part of the exhaust manifold; each move reduces the enrichment time needed to heat up the cat.

Gen2 should be much kinder to mpg's during warmup, but in lieu of the technology improvements, Gen1 owners can maximize their mpg's by minimizing short-duration ICE running.

Excellent points. Thank you for that. Had not considered what you describe here. Always learning something new, I am!

Yes, MI is likely colder than MD. But I think I beat you on snow fall - at least over this past weekend: 30" in 36 hrs.

Again, thanks for the RSVP. And sorry to hijack this from the OP, but I think all relevant/germane to the original post.
 

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Discussion Starter · #16 ·
When the gas engine began to run, MPGs blew chunks compared to summer.
Just following up with something I wrote elsewhere.

With regards to poor REX MPG initially, this is what happens to me as well in the cold.

When I have the energy screen up and watch it my MPG during that initial 5 mile run PLUMMETS LIKE A ROCK to about 18mpg, holds there for about a mile or two and then climbs fairly rapidly back to about 32-35mpg and then skyrockets back up once I switch back over to "NORMAL" mode. I have to admit that it is pretty astounding to watch how FAST it changes and how low it drops initially.

I may set up my phone cam or something and make a video. If I do I'll post it.
 

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Just following up with something I wrote elsewhere.

With regards to poor REX MPG initially, this is what happens to me as well in the cold.

When I have the energy screen up and watch it my MPG during that initial 5 mile run PLUMMETS LIKE A ROCK to about 18mpg, holds there for about a mile or two and then climbs fairly rapidly back to about 32-35mpg and then skyrockets back up once I switch back over to "NORMAL" mode. I have to admit that it is pretty astounding to watch how FAST it changes and how low it drops initially.

I may set up my phone cam or something and make a video. If I do I'll post it.
Behold the difference between warm and cold engines. :)
 
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