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Discussion Starter · #1 ·
OK, so today I picked up my daughter from school in my 2017 Volt. Left the garage on a full charge, display showing 43 miles on the guess-o-meter. Upon returning, I had gone 24 miles with an estimated 24 remaining, but...

- The battery meter was on the 6th chunk (50-60%)
- kWH used since last full charge said 4.4 kWH

If I only used 4.4 kWH on an 18.4 kWH battery, that should be only about 24% of the battery used. So why is it saying I used 40-50% of the battery if I only used 4.4 kWH of juice?

Now, I realize nothing is 100% efficient but I would think the losses would be part of that "energy used", wouldn't it? Something doesn't add up. Where am I going wrong in my thinking? Obviously I just don't understand something or one of my "assumptions" is wrong: just wondering what that is?

Thanks,
Mike
 

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Discussion Starter · #3 ·
Well, you don't get all of that 18 kWh, only about 14 is usable. That would put you closer. Is this a new Volt, it can take a few cycles to get accurate, I think.
It's not new: I got it used with 19,000 miles on it. But it might still be getting used to my driving. The first and last leg of every trip is a 5 mile run at 65 MPH so I don't expect to get 53 miles of eV range. I'm quite happy with it. I thought 18.4 kWH already took into account that GM doesn't use the full capacity. If it's closer to 14, that would explain it.

Thanks,
Mike
 

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To clarify..

The battery is indeed 18.4kWh nominal capacity. However some of the capacity is kept in reserve for hybrid/range extended mode, and the car also never charges the battery to 100% nor discharges it to 0% for battery longevity reasons.

The dash indicator only shows the 14kWh of capacity used for EV only driving. This is easily illustrated by looking at the "energy used" indicator right after the car switches into range extended mode. It will typically switch at 13.9-14.4kWh used.

The only way to see the real state of charge is via ODBII readings.
 

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It's not new: I got it used with 19,000 miles on it. But it might still be getting used to my driving. The first and last leg of every trip is a 5 mile run at 65 MPH so I don't expect to get 53 miles of eV range. I'm quite happy with it. I thought 18.4 kWH already took into account that GM doesn't use the full capacity. If it's closer to 14, that would explain it.

Thanks,
Mike
The 18.4 number is the full capacity of the battery not the available capacity which is a little over 14KWh. The Volt never fully charges or discharges the battery, 4KW is used as a guard band. This greatly extends the life of the battery which is why even Sparky, the famous Volt that has gone over 400,000 miles, has barely seen any battery degradation. For marketing reasons they quote the total capacity even though you can only use about 80% of it. Disk drive manufacturers do something similar, they quote the capacity of the disk in decimal K, i.e. 1000, rather than binary K, 1024, which is what computers actually use, on top of that they don't account for the overhead of the file system which is why your new 4 Terabyte disk shows about 3.5 Terabytes when you put it in the machine.

The range on the Guess-O-Meter is based on history, if you have a consistent driving style it should eventually settle on a number that better approximates your actual range. You may find yourself adapting your driving style to maximize the range, that's what I've done, today my Guess O Meter is at 71.
 

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Discussion Starter · #6 ·
OK, thanks. It all makes sense now. I'm really surprised how much I'm loving this car, particularly since I've had (literally) nothing but muscle cars and sports cars since I was 16 (I'm 50 now). It's just so different, so smooth, so responsive.

I've had so many cars that'll snap your neck with acceleration, this is actually something really different... and welcome. Sure, I may miss the occasional romp on the go pedal from the car I traded (2015 Challenger SRT) but I'll tell you something. No matter how fast your car is, there's always something a little bit faster. With the Volt, I feel like I have something truly unique as there is literally nothing else like it, anywhere!

Mike
 

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OK, thanks. It all makes sense now. I'm really surprised how much I'm loving this car, particularly since I've had (literally) nothing but muscle cars and sports cars since I was 16 (I'm 50 now). It's just so different, so smooth, so responsive.

I've had so many cars that'll snap your neck with acceleration, this is actually something really different... and welcome. Sure, I may miss the occasional romp on the go pedal from the car I traded (2015 Challenger SRT) but I'll tell you something. No matter how fast your car is, there's always something a little bit faster. With the Volt, I feel like I have something truly unique as there is literally nothing else like it, anywhere!

Mike
I've been there done that with the muscle car, my last car had a Hemi. You are right the Volt is completely different. I bought it because as soon as I test drove it I realized that electric cars were the future. The Volt is a transitional electric, it gives a taste to what cars will be like in the future while still having the ability to go anywhere an ICE car can. My plan is to go BEV in two or three years when the range of a reasonably priced (under $50K) reaches a practical level. The Bolt's not there, the 75KW Model 3 almost is, the addition of a couple more Supercharger locations would make the Tesla usable for me. The Volt's acceleration is decent, a little under 8 which would have qualified it as a muscle car in the 60s, but it's not neck snapping. The Bolt is 6.5 seconds 0-6 which isn't that far off of my 300C which was the standard Hemi that did 5.5 seconds, not the bored out supercharged Hemi in your SRT which was quicker. The Model 3 is exactly the same as my old Hemi, 5.5. which is as good as it ever needs to be, any quicker would just be for drag racing tracks.
 

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OK, so today I picked up my daughter from school in my 2017 Volt. Left the garage on a full charge, display showing 43 miles on the guess-o-meter. Upon returning, I had gone 24 miles with an estimated 24 remaining, but...

- The battery meter was on the 6th chunk (50-60%)
- kWH used since last full charge said 4.4 kWH

If I only used 4.4 kWH on an 18.4 kWH battery, that should be only about 24% of the battery used. So why is it saying I used 40-50% of the battery if I only used 4.4 kWH of juice?

Now, I realize nothing is 100% efficient but I would think the losses would be part of that "energy used", wouldn't it? Something doesn't add up. Where am I going wrong in my thinking? Obviously I just don't understand something or one of my "assumptions" is wrong: just wondering what that is?

Thanks,
Mike
The 43 miles on a full charge is prime suspect to me and it means you have a lead foot on the freeway with your last two recent use of the car. Now picking up your daughter from school, perhaps using a lot of non-freeway roads, it sorts of in-between guessing how you are going to use the Volt. So, you have gone 24 miles out of the usual 43, and so the battery meter shows. However, your actual consumption is on the entertainment display panel, which is only 4.4 kWH and the total usable SOC is 14.1 kWH.

If you continue to drive your Volt as you get nearer to the 14.1kWH usage mark, the bars would match the range and the kWH nearing the depletion.
 

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Discussion Starter · #9 · (Edited)
That's what the Volt is for me as well: transitional. I, however, don't know if I'll buy into full BEV until they do something like Tesla proposed a few years back (and since ditched) where the battery could drop out of the bottom for a quick "refill" via a pack exchange. I suspect about 98% of my driving will be electric only but when I want to exit the local area and take a 300-400 mile road trip, I want to know I can do it without an hour stop for a full charge. Even 15 minutes is an inconvenience when you just want to get where you are going on a long drive.

I'm glad I didn't have the money to buy a Tesla because I think that would have been a mistake for me. I work at home and do almost all local driving so the ~50 mile eV range is perfect for me. That only requires 120V to charge overnight and if you let your Tesla run down to near empty, it'd take 3 days to charge at 120V. Adding 240V service to my garage would have been another not insignificant expense because my electric panel would have to be upgraded so... electrician costs to be sure I could recharge it if I went on longer trips. I don't need that, nor do I need "ludicrous" power. I just want some pep, fun to drive, save on gas, and the ability to go anywhere without worry.

The 43 miles on a full charge is prime suspect to me and it means you have a lead foot on the freeway with your last two recent use of the car.
I drove like a granny the last couple times just to see how it would affect things and there was no difference. The meter typically shows 43-46 miles when fully charged. I think it's just that 10 miles driving at 65 MPH every trip. It's using between 15 and 20 kW to maintain that speed and I'm not putting it in hold mode at that speed: I see no need to as I know I'll make it home with battery to spare.

Mike
 

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I drove like a granny the last couple times just to see how it would affect things and there was no difference. The meter typically shows 43-46 miles when fully charged. I think it's just that 10 miles driving at 65 MPH every trip. It's using between 15 and 20 kW to maintain that speed and I'm not putting it in hold mode at that speed: I see no need to as I know I'll make it home with battery to spare.

Mike
If I drove like a granny (25-35 mph), I would get more than 100 miles per charge. Normally with 75% freeway (55-65 mph) driving and 25% city (35-45 mph) driving, I get 65-70 miles per charge. I drive about 90-150 miles per day charging at home and the office. A 43 mile after full charge could also mean that you're driving in very cold weather compared to us.
 

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Discussion Starter · #11 ·
If I drove like a granny (25-35 mph), I would get more than 100 miles per charge. Normally with 75% freeway (55-65 mph) driving and 25% city (35-45 mph) driving, I get 65-70 miles per charge. I drive about 90-150 miles per day charging at home and the office. A 43 mile after full charge could also mean that you're driving in very cold weather compared to us.
That's a bit concerning. Do you think my range is low? I'm in FL so the cold isn't going to be a factor. I do use AC and play the XM: don't know how much of an effect that has. But still, I used 4.4 kWH in 24 miles and it was telling me I had 24 miles remaining with the charge at 50-60% (6th bar). If I used 4.4 kWH and the battery has 14 kWH available, that should mean I could go a total of 76 miles. But the gauge and the guess-o-meter certainly don't seem to indicate that.

If I went 24 miles on 4.4 kWH with 24 miles remaining, it would seem to indicate that the guess-o-meter thinks I only have 8.8 kWH of battery available.

Is it possible that my battery has a lowered capacity? Keep in mind that so far, I've not drained it down past about 60% (4 bars showing). And I don't know what the previous owner did to it in the first 19,000 miles before I got it.

Mike
 

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Discussion Starter · #13 ·
I originally posted this in my other thread by mistake but...

Well, at about 6:30pm it said charge completed by 7:30pm and it indicated 47 miles of range. I just went out at 8:30pm figuring it'd be done but now it says charge completed by 8:45pm and the range has gone down to 44 miles.

Could this be an indication that the battery is having problems? Or am I just not used to the readings being screwy and this is normal?

Mike
 

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You noted that you went 24 miles with an indicated 4.4kWh. That's better than 5 miles per kWh, which is quite good, even for a gen 2.

We all know the kWh used isn't a perfectly accurate measurement, but it's not bad.

Your usage seems normal to me. I'd give things more time for you to get used to how the car reports estimated range ( which is a lot fuzzier than kWh used) and for the range estimate to settle in.

I have a commute with a big downhill at the end. This causes my estimated range to be a bit optimistic when I park. The trip home causes a big change in estimated range, as the first part of the trip is up the big hill - the the range estimate drops from being optimistic initially, to then being pessimistic ( b/c it starts figuring the high load on the uphill is going to be the norm for the reset of the trip), to being about right once i get home. This is all normal to me now, but at first it caused me some concern.


-Lumos

2014 gen 1
 

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Discussion Starter · #15 ·
I had been speculating that this was part of my problem. My house is 40 feet higher in elevation than the first traffic light toward town (4 miles away). So every time I come home, the last 4 miles are a gradual uphill climb of 40 feet. Yesterday the guess-o-meter said 33 miles at the start of that 4 miles and when I pulled into the garage, it had dropped to 24 miles: a drop of 9 miles in 4 miles of driving. I suspect that's a big contributor to my meter always showing low.

Still, it worries me that it said it had an hour left to charge with 47 miles of range. Then 2 hours later when the charge should have been long since completed, it said it still had 15 minutes left to go with only 44 miles of range. To me, taking an hour and 15 minutes longer than expected right near the end of the charge, and dropping 3 miles of range during the last 10%... sounds like it was having trouble balancing the battery pack.

Mike
 

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I think the suggestions of others to drive it until completely depleted would test if you may have a battery problem or none. Normally, you should be able to read out 14.1 kWH of electricity when the gas engine takes over.
 

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Discussion Starter · #18 ·
Too much thinking here. Just drive and stop over-analyzing the data.
I'll be the first to admit that I suffer from overthinking syndrome. I just like to know how things work and have never been able to subscribe to the "ignorance is bliss" mentality. ;) That said, seems that the recent suggestions to drive it until the ICE kicks in and see what reading I get for energy used makes the most sense. I'll do that when I can. I guess it's a good thing that I have to drive about twice my usual driving distance to get that done... but I'll add some miles to one of my trips and do it just to see.

Mike
 

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A Gen 2 Volt will use somewhere between 14.1 and 14.4 kWh before switching to 'charge sustaining' (i.e., gas) mode. If you are on the freeway it will be more like 14.1, and if you are hypermiling at 25mph with the HVAC off it will be like 14.4. I've depleted mine 14.3-14.4 a number of times when arriving home with a mile or so remaining. Have not heard anyone getting 14.5.

The 'Guess-O-Meter' will gradually learn your driving habits. Driving 24 miles round trip on 4.4 kWh is doing fine.
 

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I'll be the first to admit that I suffer from overthinking syndrome. I just like to know how things work and have never been able to subscribe to the "ignorance is bliss" mentality. ;) That said, seems that the recent suggestions to drive it until the ICE kicks in and see what reading I get for energy used makes the most sense. I'll do that when I can. I guess it's a good thing that I have to drive about twice my usual driving distance to get that done... but I'll add some miles to one of my trips and do it just to see.

Mike
All you have to do is convince yourself not to charge it for one or two nights. The usage doesn't have to take place all in one day.
 
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