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Discussion Starter #1 (Edited)
So, I’m a few weeks into owning a 2014 Volt (Ampera in my case) there have been temperatures only down to around 40f, and I notice that overnight there is no power drawn from the socket, so I guess there is no attempt to keep any battery temperature overnight ?

I’d also like to ask about preconditioning, is preconditioning for the dual purpose of heating the battery, and also providing heat output for the interior heaters / seats, mirrors, heated screen etc ?
Is preconditioning still worthwhile for warming the battery only, even if there’s no real intention of producing tonnes of interior heat, Half of the time I forget to set the heating so that it’s armed for the preconditioning... my journey to work is not so far, and I get away nicely with the seat heater
Is it a better idea to do a five to 10 minute preheat, and in this case, does it make the battery any more efficient for the start of driving since it’s warmer.... or are we just helping out the maximum range since it won’t need to draw so hard on the battery pack for the battery heater like it would have to with a stone cold battery ?

I’d just hazard a guess that if it’s close to freezing, that preconditioning whilst plugged into the wall is simply just the best way ?

Any advice most appreciated

Thanks
 

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The thermal management heater only kicks in when the battery drops below about freezing, and it takes a while for it to get that cold even if the outside temp is below that. It does not try to raise the battery temp to a high level, just keep it above freezing.

The preconditioning is specifically to warm the cabin and defrost the windows. As far as I know it is not trying to preheat the battery as well, and it probably does not make the battery work more efficiently. The range boost you get from it is because you can warm the cabin using shore power so that saves some battery power.

If your HVAC is set to fan only and you precondition, the car is smart enough to override the fan only setting and turn the heat on.
 

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So, I’m a few weeks into owning a 2014 Volt (Ampera in my case) there have been temperatures only down to around 40f, and I notice that overnight there is no power drawn from the socket, so I guess there is no attempt to keep any battery temperature overnight ?

I’d also like to ask about preconditioning, is preconditioning for the dual purpose of heating the battery, and also providing heat output for the interior heaters / seats, mirrors, heated screen etc ?
Is preconditioning still worthwhile for warming the battery only, even if there’s no real intention of producing tonnes of interior heat, Half of the time I forget to set the heating so that it’s armed for the preconditioning... my journey to work is not so far, and I get away nicely with the seat heater
Is it a better idea to do a five to 10 minute preheat, and in this case, does it make the battery any more efficient for the start of driving since it’s warmer.... or are we just helping out the maximum range since it won’t need to draw so hard on the battery pack for the battery heater like it would have to with a stone cold battery ?

I’d just hazard a guess that if it’s close to freezing, that preconditioning whilst plugged into the wall is simply just the best way ?

Any advice most appreciated

Thanks
The following applies to the Gen 2 Volt, I have no experience with your Ampera.

If the Volt is plugged in the temperature management system will heat or cool the battery pack as needed. If the temperature falls below 0C the TMS will warm the battery, maintain the battery pack temperature between 0C and 4C.

Preconditioning only warms the passenger cabin. The battery is heated separately whenever the Volt is plugged in.

Preconditioning while plugged in the way to go, conserves your battery range. The gas engine can start during preconditioning if it is cold enough. Again, this is all about pre-warming the cabin and heated seats (where equipped). The battery is taken care of by the TMS when the Volt is plugged in. A cold battery is less efficient, may be unable to charge until it has been warmed but you can drive using gas.

Your definition of cold may be different from what the Volt engineers when they designed the vehicle. Check Youtube for videos of Volts being started, driven in -31C and -40C temperatures. The Volt starts, even in the extreme cold, the gas engine immediately starts running to produce heat for the cabin and help to drive the wheels (Gen 2 only.)
 

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Discussion Starter #4
Thanks for the replies... I’m learning :)

Loving the car, seems all very well designed

I think I notice that I get better range if I unplug and drive away with a nice warm battery ? So it might be worthwhile having the charge finish right before I set off ?
 

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Thanks for the replies... I’m learning :)

Loving the car, seems all very well designed

I think I notice that I get better range if I unplug and drive away with a nice warm battery ? So it might be worthwhile having the charge finish right before I set off ?
Yes, your estimated/actual battery range can be better if you start with a battery pack that is warm as a result of just having been charged. The temperature management system will only keep the battery pack temperature above 0C (32F) and below 4C (40F.) Charging can warm the battery, at no additional cost, this will maximize the battery's chemistry when discharging and improve overall range. The optimal battery temperature is probably in the range of 29C (85F) - 32C (90F) but I don't believe charging will result in that much warming especially in winter.
 

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For whatever reason, I've noted that this year my Gen2 sucks significant additional power (according to my L2 charger) after the battery is fully charged from the previous drive. The garage temperature is above 32F. Does this sound right, or is there some setting or other issue I should be addressing?

Thanks.
 

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For whatever reason, I've noted that this year my Gen2 sucks significant additional power (according to my L2 charger) after the battery is fully charged from the previous drive. The garage temperature is above 32F. Does this sound right, or is there some setting or other issue I should be addressing?

Thanks.
Cell balancing? Cooling the battery (maybe only using the circulating pump and the radiator fan)? Charging the 12V battery?
 

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Here's a couple of graphs from my JuiceBox Pro connected to my 2018 during a chilly overnight. Car was in the garage and I think the overnight outdoor temps were in the 20s if I recall correctly. The first graph shows the charging cycles that happened every few hours and the second graph is a zoomed in picture of one of the cycles which was about 8 minutes long.


Screen Shot 2018-12-12 at 11.14.30 PM.jpg Screen Shot 2018-12-12 at 11.15.25 PM.jpg
 

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Here's a couple of graphs from my JuiceBox Pro connected to my 2018 during a chilly overnight. Car was in the garage and I think the overnight outdoor temps were in the 20s if I recall correctly. The first graph shows the charging cycles that happened every few hours and the second graph is a zoomed in picture of one of the cycles which was about 8 minutes long.


View attachment 156679 View attachment 156681
I wonder what happens if you use the OE Level 1 EVSE at the default 8 amp setting. That setting is limited to ~960W maximum. If the battery heating circuit uses ~2kW then the the high voltage battery is supplying the power to keep the battery warm, then the on-board charger needs to charge the battery to top off.
 

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This probably a silly question, but with just 10 days under my belt with our 2018 Volt LT, I have to ask: is "preconditioning" the same as "remote start"? Thanks.
 

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This probably a silly question, but with just 10 days under my belt with our 2018 Volt LT, I have to ask: is "preconditioning" the same as "remote start"? Thanks.
Yes. You can precondition your Volt's cabin using the key fob or via the MyChevrolet app provided you have an active Onstar service plan that supports the remote key fob functions.
 
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