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Here are some charts with 3 years of OnStar data. I use the OnStar diagnostic emails that I receive monthly. Temperature is the average daily temperature reported by the Capital Weather Gang from the Washington Post. For EV range I am using the kWh / 100 miles and dividing that by 1250.

I only drive locally and my driving style is basically unchanged in the last three years. I did start driving more efficiently the last two years and almost never use climate control so that has skewed the data in the last year, plus tires are now at 50 PSI compared to 42 PSI earlier in my Volt ownership.

These charts provide a pretty clear indication of the effect of temperature on EV range.



 

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Are you trying to say that outside temperatures greatly influence the range you'll get out of the battery, Ari? :)
 

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Discussion Starter #3
Are you trying to say that outside temperatures greatly influence the range you'll get out of the battery, Ari? :)
Novel idea isn't it? I'm just showing how much it does. Only temperature, not including climate control since I almost never use that "feature".
 

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When new folks come on and ask the question "why is my range dropping", save this link to give them a better explanation. It's one thing to get reassurance that this is "normal" and another to show the hard data behind what others are seeing.
 

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Thanks for putting the effort into this and it shows why an EREV or 200 mile BEV would be required to replace my wife's ICE car even though she drives a maximum of 100 miles per day.
 

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Just bought a used 2012 Volt after several test drives of the 2015 model and have been observing the 29-30 mile range on a full charge with some interest. Your graphs give me a glimpse into my own future and I am grateful for your post.

What I notice though is a step increase (large jump) in your driving range starting around August 2013?
Is this mostly due to driving style or tire pressure increase to 50 psi?

Because it seems that even on your worst day you achieved 36 miles (currently my best is say 29 miles).

Your Temps 40 deg, my temps 30-40 deg.

What is say your average speed a day? (Mine is probably around 55 mph - some in town combine with hwy at 72 mph)
My car has 45,000 miles on it and I believe a 16 kW/hr battery system. My tire pressures are 42 PSI according to TMS.
Thanks again,

GCG
 

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Discussion Starter #9
What I notice though is a step increase (large jump) in your driving range starting around August 2013?
Is this mostly due to driving style or tire pressure increase to 50 psi?
August 2013 was when I did my 313 EV mile drive in one day going for and achieving the most EV miles in one day (at that time). That really skewed my numbers that month. Not sure when I started driving consistantly using N, but it may be have been around then. Using N to coast (technically illegal in most states) really can give a significant boost to range. There are a number of discussions about it on this forum.


Because it seems that even on your worst day you achieved 36 miles (currently my best is say 29 miles).
Keep in mind I almost never use climate control, unless my wife is in the car. I'm all for maximizing range.

What is say your average speed a day? (Mine is probably around 55 mph - some in town combine with hwy at 72 mph)
I drive on mostly local roads, so for my 39 mile r/t commute I would say my average speed is probably around 35-40 MPH. My first 2 weeks of driving my Volt in Dec 2011 I found I was running out of range right before I would get home. A change to my commute to eliminate nearly all highway driving made a world of a difference and only added maybe 10 min to my commute time. I have yet to run out of range on my commute since those first 2 weeks. I do cheat on the coldest of days and do grab a 20-30 min charge to be able to complete my drive 100% EV. Last time I used the Extended Range feature of my Volt was circa May 2012.
 

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ARI,

That pretty much covered it. Considering my slightly lower temps, longer drive and highway speeds - would account for the differences in range.

I also use very little cabin comforts, as possible (mostly the seat heater on low however I did catch today that the defrost was in auto).
I've started using Neutral a bit but with hwy driving you don't get much of a chance for coasting...

I will look for a back-road route, boost tire pressure up to around 50 psi and see what's possible.
Thank you for the quick response.

GCG
 

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ARI,


I see that you post a lot and have been thanked by other members as well for your contribution.
Can you tell me if the "Engine Running Due To Temperature" (ERDTT) is as prominent in the 2012 model as it is with the 2015 model.
During my test drives of the 2015 (which is probably stored outside) this happened frequently and outside temps were say 32 deg. F. but my 2012 during morning drives (32 deg. F) never has a ERDTT.

Lastly, I can see why some drivers would prefer this not to happen or not to happen as much, but it seems to me that the seemless switching to the ICE could be better used for other driving conditions where the electric motor/batteries do not have strong performance i.e. going up hills. I would think that the ICE should have an incline or grade sensor such that it would sort of automatically go into "Mountain Mode" conserving the battery and then automatically use increased Regenerative Braking when sensing downhill grades greater than some degree???

Electric motors are extremely good at some things but when it comes to either the human occupants comfort and inclines, let the ICE do that work and conserve the battery for what it does most efficently - taking advantage of its own momentum for example...
 

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The battery has much more electrical energy to climb grades. The ICE can only supply up to it's max output from the generator. The MM saves and used both systems. On a steep climb or even heavy throttle use on level ground the 149KW motor usually uses in excess of 100KW. Use of the motor only with a low battery on long inclines has been shown to limit the Volt to top speeds in the 50's. As far as improved braking, "Low" does a very good job of it.
 

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Emissions,
I'm not sure what the abrv. MM is for (Main Motor?) but basically your saying the electric battery/motor combination does a better job on hills than the Internal Combustion Engine (ICE) (BTW - I see everyone using ICE but isn't more accurately a Generator Engine or GE).

What about the creature comforts of the cabin - if its running could it be used to supply the major source of power for the heating and cooling more efficiently than the Battery/Motor system?

I will try Low and see what that can do for me on my way home tonight!
Thanks,

GCG PS I was just reading on WIKI that the solely on battery power, maximum propulsion power is 111 kW capable of producing 149 HP while the ICE GenSet produces 63 KW of propulsion power by itself.
 

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Better Battery Chemistry allows Volt Battery to have expanded range???

Also on WIKI was this:

"As a result of its improved battery chemistry, the 2013 model year Volt increased its EPA's rated all-electric range to 38 miles"

Is there something we can do to upgrade the "chemistry" on the older model volts?

GCG PS I so want to expand the battery usage on my Volt from 10.3 KW/hr to 12.3 KW/hr!!!
 

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Discussion Starter #15
Also on WIKI was this:

"As a result of its improved battery chemistry, the 2013 model year Volt increased its EPA's rated all-electric range to 38 miles"

Is there something we can do to upgrade the "chemistry" on the older model volts?

GCG PS I so want to expand the battery usage on my Volt from 10.3 KW/hr to 12.3 KW/hr!!!
Sure, get GM to replace the battery under warranty and you will get the 16.5 kWh battery. Or I guess you could go ahead and buy one, supposedly they are around $3K.
 

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Average temperature never gets below freezing?

Pffft!

;)
 

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Discussion Starter #17
Average temperature never gets below freezing?
That's why I considered moving to Virginia. Having lived in Florida most of my life and having experienced a Syracuse winter in graduate school, I had no desire to subject myself to that again.
 

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Great data! kudos for collecting this. The takeaway is a few things:

  • Winter driving eats away ~23% of the efficiency. Except in 2013, when it took an over 30% hit.
  • Summer temperatures have little effect on range.
  • The discontinuity happens at about 50F (10C). Drop below than and efficiency takes a hit.

This is the data from a Canadian fleet study, measured EV range (= efficiency) vs temperature. They had a bigger efficiency hit with lower temperatures (over 40% between 75F and freezing).
 

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For some colder weather data:

My 2012 Volt is in a garage all night charging (37 deg. this morning when I pre-conditioned it in the garage before leaving).

Outside Temp. 8 deg. F.
Estimated driving range 28 miles on Battery. Actual 26.5 miles total of 9.1 kW/h (a approx.

Does this seem right to everyone?
 
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