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Discussion Starter #1 (Edited)
Just returned yesterday from 3 days of salmon fishing in Port Angeles, Washington. Got 3 nice King Salmon but fishing was not like it was a few years ago, but it was still enjoyable staying and fishing with family.

I drove our 2016 Volt for the trip. I was amazed that it returned great gas mpg's, when of course running on gas, 417.8 gas miles driven, 7.755 gal's used, 53.87 mpg on gas only.

Now on the way home just prior the Megler Bridge on Highway 101 on the Washington side, I switched from hold mode to electric mode as I still had 18 miles of electric range indicated, and 22 miles or so from home.

When I was about 3 miles or so from home the electric range indicated 0 miles left. I was waiting for the gas engine to fire up but it didn't. I was traveling about 45-25 mph in town at the time. The electric gauge indicate no more miles being driven on electric but now the gas miles used began to tick up for another 3 miles or so I made it home with the gas engine never firing up. So, were those electrons being now used stored somewhere in the battery when I was running in hold mode for over 200 miles, and when the battery was empty it pulled them out somewhere in the battery as having previously being stored when running on gas. I really don't know how this happened, I'm not complaining but it just seem to be a mystery...
 

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The car does some strange accounting. Since you were running in Hold mode the power the car used to keep the batteries at the hold level is attributed to the gas usage, not to wall usage. Basically the car tracks miles and efficiency based on where it believes the power came from - the gas port on the rear passenger side or the electric port on the front driver side.
 

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I saw similar behavior when my first generation Volt was newer. Doesn't happen anymore now that I think of it.

The voltage is flat across the discharge so it's difficult to estimate. You weren't going very fast so you might get 5 miles out of a kWh. And of course when you were going faster the estimated miles/kWh would have been lower than you'd actually get when going slower.
 

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Happens virtually every time I use Hold Mode. As mentioned it had a few miles built up in the battery that were put there by the ICE when in HM. Therefore it checks those off as gas miles.
 

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The gen 1 does that below 25mph

You were using the hybrid buffer that resides below your normal usable battery area

Had the engine started it would charge the buffer back up, since it didn't you used electricity from the wall.
 

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When using Hold or Mountain mode, indeed, the accounting for electric miles or gas miles driven is very iffy. I was trying to see if I can improve my MPGcs score and I found that out when driving over up and down terrains.
 

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... So, were those electrons being now used stored somewhere in the battery when I was running in hold mode for over 200 miles, and when the battery was empty it pulled them out somewhere in the battery as having previously being stored when running on gas. ...
Exactly. In Hold mode, your Volt is running as a Hybrid. Sometimes the battery is being used and discharged, and sometimes the battery is not being used and the car is recharging it. The charge level will fluctuate around the level you began Hold, sometimes you'll have more, sometimes less. In this case, you had more, when you switched back.
 

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My gen 1 would sometimes run for miles on 0 range all using electric. Never started the engine or used gas, but it did count them as "gas" miles?

 

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Assuming you didn't do a partial charge, your kWh suggests you over-regened. That is a known bug with the vehicle software. If you over-regen past full, the computer sees extra energy that shouldn't be there, and presumably assumes it must be from gas.
 

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Assuming you didn't do a partial charge, your kWh suggests you over-regened. That is a known bug with the vehicle software. If you over-regen past full, the computer sees extra energy that shouldn't be there, and presumably assumes it must be from gas.
There are several explanations for registering distances as Gas Miles without using gas, some arcane (e.g., continued downhill regen filled the upper overflow buffer, forcing the car out of Electric Mode, so distances are recorded as Gas Miles).

There are also odd explanations for registering distances as Electric Miles without using electricity. I’ve driven my 2012 Volt many an Electric Mile on Mountain Mode recharged battery power while the kWh Used and Gas Used remained unchanged.

I’m not sure if I’ve every read anything that said the use of power other than grid electricity taken from the battery could increase the kWh Used numbers, so I suspect the 15.0 kWh Used includes a partial recharge. I seem to recall reading that after a partial recharge, some owners would then unexplainedly register gas miles on that recharged power... Is this what happened here?
 

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I've gone as far as 5-10KM (3-6 miles) with the battery gauge reading zero but without the ICE starting, but it takes super careful driving to make it happen, and a little regen whenever possible doesn't hurt either.

However, when the engine finally DOES start in this scenario it runs at a more moderate RPM for a longer period of time to rebuild the buffer before falling back into the traditional.

So yes, I agree with others, you are using small portion of the normally reserved buffer in this scenario.
 

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Assuming you didn't do a partial charge, your kWh suggests you over-regened. That is a known bug with the vehicle software. If you over-regen past full, the computer sees extra energy that shouldn't be there, and presumably assumes it must be from gas.
I'm in FL. There's not many hills to regen down here, certainly not 40% SOC.

I've over regenerated coming down Saluda and the Green river gorge in NC and the car refused to use the engine to slow the car at all. It was almost as if someone threw the car in Neutral even though it was in "L" Mode. It is very disturbing to happen when you expect the car to slow sown and it just takes off and accelerates ( due to gravity ).
 

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I'm in FL. There's not many hills to regen down here, certainly not 40% SOC.

I've over regenerated coming down Saluda and the Green river gorge in NC and the car refused to use the engine to slow the car at all. It was almost as if someone threw the car in Neutral even though it was in "L" Mode. It is very disturbing to happen when you expect the car to slow sown and it just takes off and accelerates ( due to gravity ).
It actually does still offer some slowdown even after full, but severely reduced. The two motors run against each other, but there's only so much inefficiency between them. Experienced it this summer (but on purpose, I wanted to record it via OBD to see what happens)

As for your initial picture, then it's not a bug we've seen before. What I described is the only way we've seen to get more than the normal kWh used number without doing a partial charge.
 

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In a similar odd bug, I was driving in mountain mode last night and was getting close to home so thought I'd put my '17 Volt back into Normal mode for the last little stretch to burn off my 2 bars that MM holds....the electric side lit up green again but said zero miles and the motor didn't turn off and remained lit as well. I pulled over, powered down the car and then re started it and it worked in Normal mode as it was supposed to
 
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