GoldenZephyr
Posts: 11
Joined: Sat Oct 07, 2017 9:57 pm

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Mon Jan 08, 2018 7:36 pm

oilerlord wrote:
gpsman wrote: And of course, they never ever get a flat tire.



EV's don't get flat tires, however they ARE prone to "sudden tire failure". :D

The OP's issue could simply have happened due to a low 12V battery. If he's so concerned, just take the car in for service, and do the board a solid by reporting back. Who knows, there may be a TSB on this.


Ok, it obviously wasn't due to a low 12V battery. Dismissing the warning message restored full power, which wouldn't have worked if the 12V battery was low.

As for cars randomly losing power while at speed on the open road, that's clearly a safety issue. Drivers don't expect the cars in front of them to suddenly slow down, especially in the absence of brake lights or turn signals. It's not remotely paranoid to imagine this behavior leading to rear-end collisions. Imagine losing power in the middle of an intersection!

Now power loss would be expected when the high-voltage battery is depleted. Not when the gauge shows a minimum of 15 miles remaining. This is clearly a software issue. There's no need to be an apologist for bad programming.

SeanNelson
Posts: 1343
Joined: Tue Jul 05, 2016 2:43 am
Location: Vancouver, BC

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Mon Jan 08, 2018 8:38 pm

GoldenZephyr wrote:Ok, it obviously wasn't due to a low 12V battery. Dismissing the warning message restored full power, which wouldn't have worked if the 12V battery was low.

While I agree that it seems unlikely, it's still possible that a low 12V battery caused some funky condition to be set somewhere that then eventually triggered the reduced propulsion power. 12V battery issues can be a real source of gremlins for battery and hybrid electric vehicles.

GoldenZephyr
Posts: 11
Joined: Sat Oct 07, 2017 9:57 pm

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Mon Jan 08, 2018 11:39 pm

SeanNelson wrote:
GoldenZephyr wrote:Ok, it obviously wasn't due to a low 12V battery. Dismissing the warning message restored full power, which wouldn't have worked if the 12V battery was low.

While I agree that it seems unlikely, it's still possible that a low 12V battery caused some funky condition to be set somewhere that then eventually triggered the reduced propulsion power. 12V battery issues can be a real source of gremlins for battery and hybrid electric vehicles.


Hmm. I've always assumed that the 12V battery was kept fully charged by the main battery pack. I also never received any sort of error message regarding the 12V battery.

My bigger concern at the moment is my "fully charged" Bolt showing a median predicted range of 169 miles. I'm not sure where the oft-quoted 238-mile range figure originates. Maybe all downhill, with no curves, no AC, and no heat? And this is from someone who uses the regen paddle at every opportunity, and forgoes the heater (even when it's 0 degrees outside), except for intermittent windshield defrosting purposes. The combination of predicted mileage in the mid-100's, and being unable to use the last 10% or so of the battery charge without hitting the "power down" error, effectively makes this a 150-mile range vehicle.

LeftieBiker
Posts: 792
Joined: Tue Jan 10, 2017 7:13 am

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Tue Jan 09, 2018 1:16 am

My bigger concern at the moment is my "fully charged" Bolt showing a median predicted range of 169 miles. I'm not sure where the oft-quoted 238-mile range figure originates. Maybe all downhill, with no curves, no AC, and no heat? And this is from someone who uses the regen paddle at every opportunity, and forgoes the heater (even when it's 0 degrees outside), except for intermittent windshield defrosting purposes. The combination of predicted mileage in the mid-100's, and being unable to use the last 10% or so of the battery charge without hitting the "power down" error, effectively makes this a 150-mile range vehicle.


EVs are generally range tested in mild weather, with no heat or A/C. Some newer tests include some use of both, but in general range figures are to be taken as "in mild weather, at moderate speeds." It is accurate to say that in Winter, the Bolt is a 150 mile EV. My Leaf is currently a "42 mile EV." When it warms up this week it will be a "50 mile EV."

SeanNelson
Posts: 1343
Joined: Tue Jul 05, 2016 2:43 am
Location: Vancouver, BC

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Tue Jan 09, 2018 3:28 am

GoldenZephyr wrote:Hmm. I've always assumed that the 12V battery was kept fully charged by the main battery pack. I also never received any sort of error message regarding the 12V battery.

The charging protocol for the 12V battery is a lot more complex than you might expect. It's not the case that the battery is charged continuously - when the car is turned off the onboard computers check the battery state of charge only periodically and on an ever-increasing interval, and they only charge it for a set amount of time upon each check.

If the car was sitting untouched on some dealer's lot for several months, the battery may have run down enough to damage it to the point where it won't hold a proper charge even when the car is left for just a couple of days.

If the battery is low, it can lead to funky readings from the vehicle sensors which then result in mysterious codes or conditions that are extremely difficult to troubleshoot. That's why checking the 12V battery is almost always recommended whenever you see weird things happening with the vehicle.

None of this is peculiar to the Bolt - if you frequent other BEV or Hybrid forums such as those for the Prius you'll see much the same kind of discussions. It's the result of electric drive - you don't need a honking big battery to turn over the engine, but at the same time you've got these control computers that always place a drain on the battery and which tend to go a little strange if the voltages get too low.

GetOffYourGas
Posts: 1076
Joined: Tue Oct 20, 2015 5:25 pm
Location: Syracuse, NY

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Tue Jan 09, 2018 12:43 pm

GoldenZephyr wrote:
SeanNelson wrote:
GoldenZephyr wrote:Ok, it obviously wasn't due to a low 12V battery. Dismissing the warning message restored full power, which wouldn't have worked if the 12V battery was low.

While I agree that it seems unlikely, it's still possible that a low 12V battery caused some funky condition to be set somewhere that then eventually triggered the reduced propulsion power. 12V battery issues can be a real source of gremlins for battery and hybrid electric vehicles.


Hmm. I've always assumed that the 12V battery was kept fully charged by the main battery pack. I also never received any sort of error message regarding the 12V battery.

My bigger concern at the moment is my "fully charged" Bolt showing a median predicted range of 169 miles. I'm not sure where the oft-quoted 238-mile range figure originates. Maybe all downhill, with no curves, no AC, and no heat? And this is from someone who uses the regen paddle at every opportunity, and forgoes the heater (even when it's 0 degrees outside), except for intermittent windshield defrosting purposes. The combination of predicted mileage in the mid-100's, and being unable to use the last 10% or so of the battery charge without hitting the "power down" error, effectively makes this a 150-mile range vehicle.


Yup, unfortunately that's completely normal for any BEV. All cars are less efficient in the cold. Cold air is denser, causing more drag. There may be snow or slush on the road, causing more drag. In addition, BEVs don't have "free" heat from an inefficient engine, so they have to generate heat from battery power. PLUS batteries hold less energy when they are cold, so you have less energy to begin with.

In my climate (Syracuse, NY), I figure that my Bolt has, at worst case, a 100-mile range. That's dead of winter, plowing through snow, running the heat, etc. I also know from experience that during warm weather, my car will easily travel the 238 miles or more driving 65 MPH down the highway with the A/C running (contrary to ICEV experience, the A/C adds very little load whereas the heat is what really kills your range).
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
2012 Leaf SV (traded for Bolt)
2015 C-Max Energi (302A package)
2017 Bolt Premier

GoldenZephyr
Posts: 11
Joined: Sat Oct 07, 2017 9:57 pm

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Tue Jan 09, 2018 9:55 pm

Yes, 100 mile range (running heat full blast), or 150 mile range using it only for windshield defrosting sounds about right in the northeast, during Winter. 100 or even 150 miles is not equivalent to 238 miles, however, and an approximate Winter range (say, road tested at 32 degrees, with interior heat running and thermostat set at 62 degrees), would be extremely helpful information to have posted on the car's window decal while it sits in a dealer's lot. About 170 miles before sudden power loss was all my Bolt could achieve on my recent trip, without the heat on except for defrosting. It was a depressing drive, made more so by the fact that the interior car temperature hovered near the below-freezing exterior temp (because I kept the heat off to conserve power). It was like driving through a snowstorm in a convertible.

The current situation, in which only the 238-mile figure is quoted, would be equivalent to the window decals on ICE cars mentioning only the highway MPG, without even noting that it's the highway MPG. Actually, it's worse than that, since having your ICE car run out of gas sooner than you expect just means looking for a ubiquitous gas station for a 5-minute fill-up, whereas when your BEV runs out of charge prematurely, you're probably calling for a tow truck...

I imagine that in a few years, when regulators catch up to the issues specific to BEV's, there will be a requirement for more realistic and detailed range estimates to be provided by manufacturers. Until then, unless you live in CA or some other "not too hot, not too cold" part of the country, it's definitely a case of caveat emptor.

LeftieBiker
Posts: 792
Joined: Tue Jan 10, 2017 7:13 am

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Tue Jan 09, 2018 11:33 pm

All true. In the meantime, I suggest we tell people that an EV has "about half" the range in Winter as in mild weather, or half what is posted as the official range..

DNAinaGoodWay
Posts: 246
Joined: Fri Sep 23, 2016 11:19 am
Location: Central Massachusetts

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Fri Jan 12, 2018 9:52 am

There’s a couple more reports on the Facebook group of this OP’s problem. Both early builds under the recall. New packs installed, issue resolved.
Leaf SL 2012-2014
Leaf SV 2014-2017
Bolt LT 2017-
6.72 kW Solar

winterescape
Posts: 150
Joined: Sun Jun 25, 2017 1:35 pm
Location: Upstate, NY

Re: Bolt EV powers down while driving, with "Minimum" 15 miles charge remaining

Fri Jan 12, 2018 12:55 pm

DNAinaGoodWay wrote:There’s a couple more reports on the Facebook group of this OP’s problem. Both early builds under the recall. New packs installed, issue resolved.


Good to know, thanks for the updated info

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