GM Volt Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
601 Posts
I got home last night with my MY2012 Volt with 4 miles range left on the guess-o-meter. I left it parked in the driveway as my wife was charging her Volt at the time. Within 15 minutes of getting home we were off with friends to a church function. About 2 1/2 hours later we got back home, my wife's volt was finished charging so we moved hers out of the way. I then got in mine to move it up the driveway so I could charge it. I was really surprised that the 4 miles of range I had when I parked it about 3 hours earlier was now gone, and it immediately showed me being on fossil fuel. Since it was raining, I knew it was not due to cold temps. What could cause the 4 miles to disappear in a matter of 3 hours and not running?
 

·
Registered
Joined
·
4,405 Posts
I got home last night with my MY2012 Volt with 4 miles range left on the guess-o-meter. I left it parked in the driveway as my wife was charging her Volt at the time. Within 15 minutes of getting home we were off with friends to a church function. About 2 1/2 hours later we got back home, my wife's volt was finished charging so we moved hers out of the way. I then got in mine to move it up the driveway so I could charge it. I was really surprised that the 4 miles of range I had when I parked it about 3 hours earlier was now gone, and it immediately showed me being on fossil fuel. Since it was raining, I knew it was not due to cold temps. What could cause the 4 miles to disappear in a matter of 3 hours and not running?
Did you leave the IGN on? It's a common occurrence on G1's. We did this a couple times, hence why there was a reflash about it.

Another? Any teens in the household? I used to "borrow" my parent's cars up until I was caught.

Unknown to me - Battery conditioning in cold weather. That's a wild guess. I have not seen that because we plug in when parked.
 

·
Registered
Joined
·
2,130 Posts
I got home last night with my MY2012 Volt with 4 miles range left on the guess-o-meter. I left it parked in the driveway as my wife was charging her Volt at the time. Within 15 minutes of getting home we were off with friends to a church function. About 2 1/2 hours later we got back home, my wife's volt was finished charging so we moved hers out of the way. I then got in mine to move it up the driveway so I could charge it. I was really surprised that the 4 miles of range I had when I parked it about 3 hours earlier was now gone, and it immediately showed me being on fossil fuel. Since it was raining, I knew it was not due to cold temps. What could cause the 4 miles to disappear in a matter of 3 hours and not running?
Normal behavior considering that number is nothing more than an estimate based on numerous criteria.

BTW - MY2012 is redundant, 2012 means model year 2012 :)
 

·
Registered
Joined
·
1,314 Posts
I've had a couple miles "disappear" before, not sure 4 but definitely 1 or 2. Batteries are tricky things, they are not like gas tanks with their fixed volume of liquid. If you're actively using a battery, it's voltage might be x. But if you let it rest a while (sometimes even just 10 minutes), the voltage can drop a bit... if you're near the lower state-of-charge window already, this lower voltage might be enough for the computer to decide the pack is depleted (I don't know exactly how they determine this, but surely it tries to integrate energy usage over time, but also must have low-voltage-cutoff type sensing). I pretty much expect that if I park with 1 mile left, it will be gone when I turn the car back on. This only seems to happen at lower charge levels, I don't notice it with mid or high levels of charge (though of course the guess-o-meter can change at any time for many reasons, so maybe I just haven't noticed it).

I've seen this in the RC (radio controlled) world... you get the longest flights when you're charging and using the same pack over and over (charging one pack while flying another, rinse and repeat). Whereas even if you had just charged that pack yesterday, it won't perform as well because the voltage sagged a bit.
 

·
Registered
Joined
·
777 Posts
I agree 100% with Joe67, normal behavior.

Consider that when you first parked, the estimation program calculated how far you could go on a warm battery. After 3 hours, your battery cooled off some and when the estimation program ran again, using the current battery temperature as input, decided you have 0 miles left.
 

·
Registered
Joined
·
261 Posts
I think there are gremlins living under the hood that like to eat miles. I occasionally see a loss of miles on my 2016 in hold mode. Not sure why, but not too concerned about it, either. Actually, I think air and battery temps are the biggest factors here.
 

·
Registered
Joined
·
347 Posts
I have a 2011. I charge it and back it on to the driveway (about 20 feet), and leave it for a few hours. Upon restarting the range estimate goes down by 10-11 miles, but its a bogus estimate as my actual range has not changed.
 

·
Registered
Joined
·
1,034 Posts
The EV Range Estimate does indeed have a mind of it's own, but it is probably smarter that you and most others give it credit for. Most likely when you parked your Volt it was basing the range projection on historical data, how you had been driving just prior to parking it, the outside temp, etc. When you started it back up 3 hours later I'll bet the temp. had dropped, the battery charge had probably slumped a little, etc. therefore it activated the ICE and said you could go no further on battery. I've seen it many times on the other end of the temperature scale in Arizona and in as little as 10-15 minutes.

VIN # B0985
 

·
Registered
Joined
·
1,890 Posts
I agree that this kind of thing happens with Volts and doesn't indicate a problem. But I hesitate to agree in calling it "normal".

I've lost up to 3 miles before in moderate temps when only leaving the car for 10 minutes. (Nothing to do with battery temps there.) I call that "unacceptable".

To most of us, the battery pack and its associated controls software/logic is a black box. But my understanding of battery pack controls is that usually direct measurements of pack/cell voltages are what is used to determine when a battery is "empty". And yet the voltage of Li-Ion packs/cells actually rebounds (increases) when no load is placed on it for several minutes (like when the car is off). So the fact that you often lose miles after turning off and restarting the car makes little sense to me.

So, as an engineer trying to understand why my Volt often under-performs expectations in this way with no obvious explanation that I can think of, it's particularly frustrating.
 

·
Registered
Joined
·
84 Posts
I have observed this countless times on my 2013, and consider it 'normal'. IIRC, what I found when monitoring things with MyGreenVolt is that my Volt keeps the SOC around 19% when the battery has been depleted and it is running on fuel. However, I have been able to drive the SOC down to 15-16% at the end of a drive without the ICE starting up and showing 1-2 miles on the GOM by slowing down and using gentle acceleration the last mile or two. When I power the vehicle off and back on, these 'ghost' miles disappear.
What may be happening is that the car disregards any 'miles' from the previous cycle when it is below this ~19% SOC threshold. If you notice when you start under this condition, you can still do some light-footed acceleration (albeit very limited) before the ICE actually starts. The juice is still there, the car simply changes mode and operates under assumption that the ICE will be providing all the power and brings the battery back up to ~19% SOC as you begin driving.
 

·
Registered
Joined
·
601 Posts
Discussion Starter #11
Thanks to all.... I just consider it the nature of the beast and just keep driving and enjoying it.
 

·
Registered
Joined
·
1,536 Posts
Consider, too, that a range estimate is simple math: average mileage x available fuel.

When the Volt is parked for a time, the computer draws additional data and, if needed, updates the battery soc estimate, which may or may not change the amount of available fuel that had been used to calculate the range estimate... any fuel consumed for battery maintenance while parked also impacts the amount of available fuel... and environmental conditions while parked (e.g., 3 hours of sitting in the rain) might have impacted the algorithm used to calculate the average mileage portion of the range estimate calculation.
 

·
Registered
Joined
·
1,261 Posts
It's not unusual to go to CS mode when parked with 5 miles or less. I've parked with 5, come back later to "0." Sometimes, the engine will switch on right away, other times, I'll start the car and it will be in CS mode, but may get anywhere from 3-5 additional EV miles before the engine starts.

It's definitely an art, not a science, for the car to figure out the last handful of miles left. Because of this uncertainty, I rarely park the car with less than 5 miles if I can help it. I may use hold to keep 6+ miles as then I'm confident that I'll get back in the car with at least some EV miles remaining.

It's one of the few things I don't like about the Volt, despite knowing the difficulty with calculating this information. Obviously, with full BEVs I hope the issue is not a problem as I wouldn't want people stopping with 3 miles left thinking they can get to their home 1 mile away--and then restart to an "empty" battery. My guess is the software will have a buffer for these scenarios. The beauty of the Volt is that our "buffer" is a range extender.
 

·
Registered
Joined
·
1,051 Posts
My 2013 has done the same thing before. I lost 3 miles in 15 minutes last week when I stopped for lunch. Outside temp was about 4F. I figured it was due to a colder battery pushing a few less volts. No problem though, I burned a cup of gas driving home and plugged in to recharge.
 

·
Registered
Joined
·
244 Posts
My estimated range seems pretty stable. I have left the car parked in the driveway for a week or more with no change. However, the car always had a full charge.
 

·
Registered
Joined
·
3,945 Posts
I agree that this kind of thing happens with Volts and doesn't indicate a problem. But I hesitate to agree in calling it "normal".

I've lost up to 3 miles before in moderate temps when only leaving the car for 10 minutes. (Nothing to do with battery temps there.) I call that "unacceptable".
I'm pretty sure there was a bulletin for that small range drop when parked.
 

·
Registered
Joined
·
1,261 Posts
I'm pretty sure there was a bulletin for that small range drop when parked.
Yes, if you lose more than 5-7 miles--but only on 2013s that had HPCM #2 reset during a specified time. It's Bulletin #PIC6138. I don't think that applies to this specific circumstance here. These drops would generally only occur between 10 to 30 remaining EV miles, but didn't really affect SOC calculations at the lower and higher end of the estimate.
 

·
Registered
Joined
·
208 Posts
I have often driven across the state to visit relatives,and when I get back in town, I will stop and fill up my gas tank.
even though I get 380 miles per full tank, the guess meter will show a 3/4 full tank of fuel,even though the tank is full
the guess meter will show 8,8 gallons in the tank
I just ignore it and drive normally
 
1 - 18 of 18 Posts
Top