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Discussion Starter · #1 ·
What determines the EV range that is displayed? Is it just a guess based on the temperature or is it somehow constantly adjusting based on driving habits, temperature, etc.?

When I got my car in October the EV range went as high as 57 miles while it was in the 60s and 70s outside. Yesterday I ran the car to 0 EV range and drove on the ICE so the battery got a full recharge last night. Today it's about 52 degrees outside and the car is only showing 40 miles EV range.

I'm wondering if this is just the car guessing based on the most recent conditions and after I drive it and recharge it today the range will actually increase... or is this the actual max range I will get right now? Is the car just assuming that I will use the heater, heated seats, drive a certain way, etc. and combining that with the air temperature to say 40 miles, so if I were to drive without the heater on I would get more?
 

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It's a combination of many factors based on your previous driving, driving technique, temperature aka weather, terrain, tire pressures and HVAC usage.

It's a moving number. That's why we call it the Guess-O-Meter.
 

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It's a quess by the computer based on your last drive or 2.
Exactly, and here's a good example of how the driving behavior comes into play: right now our weather is around 40F and my estimated range was around 65-68 (don't use HVAC much), but after 3 driving sessions by my wife and daughter that covered a total of about 70 miles (different driving style and they do use HVAC much), today I got in the car and the estimate had gone down to 55 (about 20% less) with the same outdoor temp.
 

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I would guess it's using recent miles/kWh from previous cycles. The only problem with that is it seems to switch to using a shorter time frame average while driving. Mine goes like this, leave the house with high 40's, get to work it's 38-40 and then head home which is 23 miles and now have to switch to gas part way home. It doesn't know I can get 4 m/kWh going to work and am closer to 2 on the way home.
 

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Downhill, uphill maybe?
 

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Discussion Starter · #7 ·
Okay thanks... so it sounds like the number isn't really tied to what the car will try to use. I was just concerned that somehow my range had gone down and now the car isn't recovering as much range because it thinks the battery is full when it really isn't or something. It seems like I saw a few posts with issues around the battery level and the car not fully recharging or not using all of the available charge.
 

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If you drive without the heater on, you might eek out a few more miles, but the car still needs the heater to warm the battery. I'm surprised you're asking this question since you've been on this forum for years. You can also affect it negatively by driving like Jeff Gordon and positively by driving it like a grandpa. Or switch from your regular commute to a long trip soemwhere, and the numbers will change, then return back to normal when you change back.
 

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Discussion Starter · #9 ·
If you drive without the heater on, you might eek out a few more miles, but the car still needs the heater to warm the battery. I'm surprised you're asking this question since you've been on this forum for years. You can also affect it negatively by driving like Jeff Gordon and positively by driving it like a grandpa. Or switch from your regular commute to a long trip soemwhere, and the numbers will change, then return back to normal when you change back.
Okay thanks... I've been lurking for years but just got my first Volt two months ago :)

Just wanted to make sure there weren't any odd things that needed to be done like reset the way the car senses the current charge level or something. Since I just had to get the transmission replaced (see other thread) I'm wanting to make sure there aren't any reset procedures or other software fixes that need to be done.
 

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At the end of your charging session, if you have 10 bars lit on the DIC, you have a full charge.
 

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Every night, you eat out. For the last 3 nights, you spent an average of $50 at your favorite restaurant. My guess is you'll spend $50 tonight.

That's what the car is doing.

Now if you change restaurants, or eat more, eat less, have more beverages or less, this can throw off the estimate. Same with the car, but related to driving style, tire pressure, outside temps, the roads you travel, etc.
 

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A range estimate is simple math: average mileage x available fuel.

The full charge range estimates and the "as you drive" range estimates employ different methods of calculating average mileage.

The algorithm used to create the full-charge, or start of day average mileage estimate, is based on historical driving data, weighted for recent data, and tends to be fuel-specific. Last night’s temperature impacted the mileage you got while driving home last night. That mileage plays a greater role in today’s start of day average mileage estimate than does this morning’s temperature.

If ERDTT and short distances driven on a cold engine are your only use of the ICE, your start of day gas range estimates will be low, even with a full tank of gas, based on this recent low mileage use of gas.

Of, if your electric driving is very efficient, but you only drive 10 miles a day, your fully charged Gen 2 Volt might show a full charge ev range estimate of 70-80+ miles, based on your efficient short-distance ev driving.

Once you start driving, mileage estimates change, based on "on the fly" environment, terrain, power used for accessories, and driving habit data feedback. When driving on battery power, the ev range estimates change both as fuel is consumed and driving efficiency is modified. Note that the "on the fly" data feedback may also be applied to the average mileage estimate of the fuel not being used, producing a change in the gas range estimate, even if the ICE is never turned on.

My 2012 Volt has no Hold mode, so I do not know if the reverse is true, if the ev range estimate would change, based only on "on the fly data feedback" while driving in Extended Range Mode.
 

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If you drive without the heater on, you might eek out a few more miles, but the car still needs the heater to warm the battery. <snip>
I've seen you and others say that the cabin heater heats the HV battery. AFAIK this is not so. There is a separate heating/cooling circuit for this battery and there is a separate element and module for heating this circuit. Here are two citations:

http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/

http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/
 

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I've seen you and others say that the cabin heater heats the HV battery. AFAIK this is not so. There is a separate heating/cooling circuit for this battery and there is a separate element and module for heating this circuit. Here are two citations:

http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/

http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/
My point was that even if you turn the heater off, the car will still heat itself to keep the battery warm. I didn't get into the specifics about the different heaters and loops. Personally, I'd rather be warm and blow my EV mileage than be one of those crazy people who don a snowmobile outfit and disable ERDTT to gain a few miles or avoid a fuel burn. Especially when I am known to take on any and all pony cars at stoplights. With all this abuse, I'm still achieving 70 mpg lifetime, way better than any Prius - except now maybe the Prius prime is getting close to achieving gen1 numbers.
 

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My point was that even if you turn the heater off, the car will still heat itself to keep the battery warm. I didn't get into the specifics about the different heaters and loops. Personally, I'd rather be warm and blow my EV mileage than be one of those crazy people who don a snowmobile outfit and disable ERDTT to gain a few miles or avoid a fuel burn. Especially when I am known to take on any and all pony cars at stoplights. With all this abuse, I'm still achieving 70 mpg lifetime, way better than any Prius - except now maybe the Prius prime is getting close to achieving gen1 numbers.
I agree with your sentiments. I drove my 2012 in ways to maximize my numbers and still only achieved a lifetime mpg of 87.5. Maybe driving only 52% in CD mode (17186 miles out of 33063) contributed to that.

I'm doing even worst in my 2014 (currently 56.9 mpg); only 26% in CD mode (10538 miles out of 40881) but I've done two cross-country trips and a number of trips to Florida, always in CD mode while away from home. Funny, my ICE stat is nearly the same for both cars: 38.6 mpg lifetime average from 15,877 miles in CS mode in the 2012 and 37.9 mpg lifetime average from 30,382 miles in CS mode in the 2014. Locally, if I have passengers, I switch to Hold mode, punch the Auto button and generate comfortable cabin heat. If I'm alone, I'll drive without heat most days, relying on the heated seat to keep me semi-comfortable. Local trips are under 25 minutes, tops, so I'm not in the icebox for long.

The Volt is the car that has best suited my needs, being the most comfortable, the most economical, the quietest, the sportiest when I want it to be, surpassing the 1965 Porsche 356SC cabriolet I owned, and hands down the best road car of all the cars I have owned.

The 1965 Porsche 365SC cabriolet was a beauty. Mine was in a dark blue. I paid a little over $4,000 for it (probably half my annual salary, but I was single so what-the-hay). Look at what it can cost now: https://www.hemmings.com/classifieds/cars-for-sale/porsche/356sc/1901283.html
 

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My point was that even if you turn the heater off, the car will still heat itself to keep the battery warm. I didn't get into the specifics about the different heaters and loops. Personally, I'd rather be warm and blow my EV mileage than be one of those crazy people who don a snowmobile outfit and disable ERDTT to gain a few miles or avoid a fuel burn. Especially when I am known to take on any and all pony cars at stoplights. With all this abuse, I'm still achieving 70 mpg lifetime, way better than any Prius - except now maybe the Prius prime is getting close to achieving gen1 numbers.
It probably is. Too bad there still doesn't seem to be a "PriusStats" website. :) (Fuelly is okay for guessing what the overall average mpg is (~46mpg) for all Priuses, but it's all self-reported and nobody seems to know wtf kind of Prius they got. (don't laugh, the Volt figures there are worse).) (Did I get all the parens right there?)
 
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