[imanjunk1963]

So I am just wondering how is it possible for me to get 10.9 kWh out of my battery when its only rated 10.7 for 2014 usable, its going on 5 years old with about 56k miles on it. Im not complaining just wondering how. During the winter I noticed on average its down to 10.2 kWh but during this summer I have seen it get 10.5 and then now and then 10.7 and above or like today 10.9 as shown in the picture. And it was just typical driving which after I used a 0.10 gallon of gas to get the rest of the way home once the battery was used up. See picture.

 

[Orienteer]

Regen! If you happened to coast a lot during this cycle, you ended up putting in the extra watts which get counted towards total usage.

 

[VoltenRock]

Variations of 0.2 to 0.5 off your typical kWh used is within normal range of the estimate. It’s just an estimate, not an actual meter. The only time for real concern is if you start dipping into the low 9s and showing loss of actual EV RANGE.

These are typical variations. My Gen 1 2013 was 10.0-10.5, my Gen 2 is 13.8-14.4.

 

[wordptom]

The 2014 Volt has a 16.5 kWh battery, with a ~65% usable window (~10.7 kWh usable). Each 0.1 kWh is therefore only 1/165 = ~0.6% of the full capacity. The usable state of charge window is usually thought to be between a 20-22% "switch to gas" soc and a 85-87% "full charge" soc (which, if you think about it, is a "usable window" of 63-67%). Perhaps on this particular day, charging conditions had produced a "full charge" soc around 87.5%, and perhaps you were driving under moderate conditions with little power demand as the battery charge dropped to the cutoff point, so the computer chose to switch you to gas just as the charge dropped to the 21.5% soc level. On this particular day, the slight increase in the "full charge" soc, combined with a slight delay in the switching to gas soc produced circumstances that resulted in a usable window of ~66%, creating a kWh Used = 10.9 kWh. On other days, "full charge" might have been reached at a slightly lower soc point, or driving conditions might result in switching to gas at an soc slightly above the calculated level, slightly shrinking the usable window into the 64+% range, giving a kWh Used number below 10.7.

It’s not because of regen... the kWh Used number on the energy usage display is not a meter reading, but a net calculation: grid power used less regen put back into the battery (if you drive down a long hill in Electric Mode, you may see the kWh Used number decrease as the amount of regen created increases).

 

[hosedup]

Regen! If you happened to coast a lot during this cycle, you ended up putting in the extra watts which get counted towards total usage.

Regen is not the reason. If you watch the kWh used as you regen, the kWh number will go down. Actually you should be watching the road Seriously though, drive to the top of a big hill, make mental note of kWh used, then regen all the way down to the bottom coming to a near stop and you will see that the number did decrease. I agree with what VoltenRock said as the reason.

 

[FI Spyder]

Saw 13.4 Kw used on display after shutting down on last out of town trip on my 2013. I drove from full, last bit on gas to save some electric, charged up fully from near empty on free charge at mall, drove home in the dark with lights on 70 Km with last bit on gas (auto change over). The road has some hills but over all is same altitude. Is the amount additive or just calculates amount used since last charge? Seems high or do I have a really good battery?

 

[hellsop]

Saw 13.4 Kw used on display after shutting down on last out of town trip on my 2013. I drove from full, last bit on gas to save some electric, charged up fully from near empty on free charge at mall, drove home in the dark with lights on 70 Km with last bit on gas (auto change over). The road has some hills but over all is same altitude. Is the amount additive or just calculates amount used since last charge? Seems high or do I have a really good battery?

Meter resets on a charge to full. So the addition at the mall didn't take you there, and therefore it just got added on.

 

[Steverino]

Variations of 0.2 to 0.5 off your typical kWh used is within normal range of the estimate. It’s just an estimate, not an actual meter. The only time for real concern is if you start dipping into the low 9s and showing loss of actual EV RANGE.

These are typical variations. My Gen 1 2013 was 10.0-10.5, my Gen 2 is 13.8-14.4.

Correct, the display of kWh Used is an estimate, not a meter reading.

 

[FI Spyder]

Meter resets on a charge to full. So the addition at the mall didn't take you there, and therefore it just got added on.

The charge at the Mall was a full charge (green light blinking on dash as well the Chargepoint email said it was a full charge as a back up indicator) so it should have then been reset. If it was additive it should have shown as about 20 Kw. used unless something else was going on.

 

[hellsop]

So I am just wondering how is it possible for me to get 10.9 kWh out of my battery when its only rated 10.7 for 2014 usable, its going on 5 years old with about 56k miles on it. Im not complaining just wondering how. During the winter I noticed on average its down to 10.2 kWh but during this summer I have seen it get 10.5 and then now and then 10.7 and above or like today 10.9 as shown in the picture. And it was just typical driving which after I used a 0.10 gallon of gas to get the rest of the way home once the battery was used up. See picture. View attachment 155457

Generally speaking, as others said "It's not a meter". Technically, it's metering the output, but the decisions about what to do when are made by VOLTAGE from the pack, and voltage alone. If you take power out of a battery SLOWLY, the voltage will stay higher compared to how much power you've extracted than if you drain it quickly. Winter gets heater use (up to 6 kw), it's harder to push cold components like tires and grease around, so the car has to pull power out of the battery faster to do the same job. That means fewer electrons come out before the battery voltage goes down to the magic threshold of "Time to turn on the engine!". You'll see the same effect if you compare how much power you get out at 75MPH vs 30 MPH.

(There are many magic thresholds, all based on voltages: "Turn on CS mode" is ever so slightly above "Turn on ICE in CS Mode", and well below "Turn off ICE while in CS mode". Hold Mode comes with its own "Turn on Hold Mode" point that is set when you turn it on, that has corresponding "turn on ICE in Hold Mode" and "turn off ICE in Hold Mode" points. Mountain Mode has a "turn off ICE" point. Below the CS one is a "Propulsion Power Reduced" point, and below that one is an even more dreaded "shift to park" level of voltage. But they're all VOLTAGES so they move around a little bit in relation to each other and what you've been doing, based on many things. I'm convinced that older Gen 1 batteries in model years with self-adjusting windows sometime can let "turn on CS mode" get too close to "PPR" to the point that the car can move past CS into PPR faster than it should and that's why we saw a rash of "My 2013 almost killed my wife on the freeway" posts until GM understood what's going on and pushed a fix to dealers.)

 

[canehdian]

To further what wordptom and hellsop have stated, it's a combination of the two.
The kWh calculation is a meter (despite the mantra always thrown around), in that a meter takes measured inputs (voltage, amps) and increments the output value (kWh) - the same as your house grid meter would. What they likely mean to say is that the kWh display is not necessarily a meter of battery health or capacity.
The part that's fuzzy is the start and end points, which are always fluctuating.

The top charge point is highly based on temperature of the cells. I've seen it naturally charge anywhere from 81-87%, after resting and allowing temperature (and voltage) to settle. The charger is programmed to aim for a specific voltage, which corresponds to 83.5% SOC. Problem is, the computer typically overrides the SOC when receiving a 'charge full' signal. Always 83.5%. Normally, that's ok, but if there is a significant change in the state of the battery by the time you drive, you're not really at 83.5%.
In the winter, the cells may cool down and you're actually at 81%. In the summer they may warm up and you're actually at 85%. But the charger is working to 83% in both situations. If you're starting at 81% you're already 0.3kWh off of the theoretical "full charge". Conversely, if your battery was cold and you topped off the charge back to full - you could get more than "full charge" if the temperature warms up by the time the battery is used.

And at the bottom, as hellsop said, depending on the load on the battery, the voltage may dip too far and cause it to switch over to ICE even though there would still be some energy left to continue in EV mode under a lighter load.

In short, you pretty much never have a textbook "full charge" available as your start and end points are always floating.
Between those two points though, I've found it to be incredibly accurate - it is metering that value correctly.
i.e. if it says 10.9, you used 10.9 and that's how much will be refilled from the wall (not counting losses). Doesn't mean your battery is necessarily any better or worse than a day it says 10.2, however.

 

[hellsop]

In short, you pretty much never have a textbook "full charge" available as your start and end points are always floating.
Between those two points though, I've found it to be incredibly accurate - it is metering that value correctly.
i.e. if it says 10.9, you used 10.9 and that's how much will be refilled from the wall (not counting losses). Doesn't mean your battery is necessarily any better or worse than a day it says 10.2, however.

Yup. It can count electrons coming out pretty good. It just doesn't seem to use that count for much of anything beyond display. It's not like it gets to "Well, you've used 10.2 kwh, time to put on the engine!" That's a "the battery voltage got low enough"-triggered event. As are most things.

I'd like to elaborate this, though:

The top charge point is highly based on temperature of the cells. I've seen it naturally charge anywhere from 81-87%, after resting and allowing temperature (and voltage) to settle.

Not because it's wrong, but (in more more general battery charging than just Volt) because the temperature rise is the signal not that it's done charging but it is an indication that the battery is done with the bulk charge cycle and finishing charging safely means switching from constant-current "take everything it can get" charging, to a limited-current charging to (finally) constant voltage (at the nominal "full charge" voltage level, which automatically supplies an appropriate taper). This also happens to be about where Volts stop charging batteries (80-85%), but Volts stop charging well before "safe full". And it's not where (for example) Bolts stop. They'll charge much higher than just the end of bulk charge, and do a taper or two before that thermal rise (as a "preemptive absorption" if you like) before that so they reach that mark at quite so fast a rate, with a lot of latent heat still to manifest.