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Discussion Starter #1
Hi all,

I checked the manual but couldn’t find a definitive answer to a concern I have.

I currently have a 2018 Volt that I got back in May and really love. I charge every night in my detached garage using the 110 cord. I pretty much wipe my charge each day due to a 46 mile round trip to work. Depends on the time of year as I’m finding out as colder weather approaches here in Massachusetts.

It’s now time to replace my wife’s car. A Bolt is on the short list of vehicles. My issue is that the wiring to my detached garage is barely suitable to support my 110 cord for my Volt. There’s no way I can charge another vehicle in there at the same time.

In the spring we plan to have a new line run to the garage that will support two level 2 chargers. The trick is getting by until then.

My wife’s commute is about half of what
mine is so we could get by using the 110 cord in the garage on the weekend to give her enough of a charge for the week. My car would be on the cord each weeknight. I could always run on gas for a day if she needed the cord during the week.

My concern is that this temporary arrangement would mean that one car or the other, my Volt or her Bolt, would be plugged in at a time. Is this going to put either vehicle at risk during a Massachusetts winter?

Thanks in advance for any advice.
 

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Ah yes. The Dreaded Winter cometh.

Yes. You need to (or should) be plugging both of these cars in for TMS reasons.
Will it harm either if you don't? Who knows.... It is not ideal for a Li-Ion battery pack to operate at very low temps.

Buy a 12 ga. extension cord that will reach to another dedicated outlet in the house until the dual L2's are up and running.
Go for dual 7.2kW capabilities ! Now that's a future proof garage!

Actually the Bolt could nightly use the L1 on 8A for just TMS reasons if you only want to purchase one of the L2's for now.
But definitely run the heavy wire to the sub-box in the garage now.

Oops edit.....
 

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Discussion Starter #3
Thanks for the good suggestions. I do have another outlet on the house that I could plug the extension cord into, at least on the 8 amp setting for battery maintenance.

On that same thought, if it happens to be a frigid 5 degree day and my Volt sits in the parking lot at work unplugged all day, is that putting the battery at risk? I think that’s a fairly realistic scenario for folks that live in cold climates.
 

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....On that same thought, if it happens to be a frigid 5 degree day and my Volt sits in the parking lot at work unplugged all day, is that putting the battery at risk? ....
Not ideal. But what are you going to do? It's a car. It can't be pampered 100% of the time.
There is a very low Temp Point where the Gen1 Volt gets 'Bricked' because it won't use the HV Battery to start the engine.
You get a "Must Plug In" msg to warm the HV Battery.
I assume the Gen2 Volt might be similar.
 

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I would purchase a 12 or 10 gauge cord, and run it, not 20 gauge possibly a typo.
BTW, most cords are rated for 300 volts so if you had an adapter to a 208-240 v circuit, you could use the charger on that. Possibly a dryer or range plug adapter. That would probably be a good way to charge the Bolt on the weekend, until you get a 60 amp or greater sub panel in the garage.
 

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You won't cause any damage to your 2018 Volt if you don't plug in during cold weather. The Volt's temperature management system (TMS) will delay charging the battery until you do plug in and/or the battery has warmed to the minimum temperature needed to charge (~32F). When you start the Volt the gas engine will start automatically if the temperature is below 35F or 15F (if the Engine Assist Heat setting is set to deferred.) Engine Assist Heat will warm the cabin, the battery relies on the TMS to manage the battery temperature and uses an electric heating element to warm the battery as required. If the gas engine is running due to temperature (ERDTT) the engine will cycle on and off after initially running to warm the engine coolant to 160F, then maintain the engine coolant between 120F and 140F. The Volt will also run on the battery in cold weather provided there is sufficient battery charge, then switch to the gas engine. In very cold weather battery range will be reduced by at least 25%, your commute may then involve using some gas that would not be required in warmer conditions.

If you want to see how a Volt performs in extremely cold temperatures there are some Youtube videos of the Volt being started, driven in -25F and -40F conditions. Also, I recall a video where GM engineers cold soaked a Volt in a large refrigerated storage locker and then drove the car. While you are unlikely to have this issue, it is possible for the Volt's 12V AGM battery to get so cold that it could freeze, be unable to boot up the Volt's systems. Plugging in the Volt does not address this issue as the 12V battery is not warmed even when the Volt is plugged in. In the unlikely scenario where the 12V battery is too cold to start the Volt you may want to keep a fully charged portable 12V jump starter pack inside the house, warm and ready to be used, as a contingency plan for starting the Volt using the 12V battery jump start terminals located under the hood in the engine compartment (see your Owner's Manual for details.)

If both vehicles are parked in the garage, in very cold weather only, you could use an electric space heater or a properly ventilated kerosene or propane fueled heater inside the garage. Ideally you would want to keep the temperature of your vehicle batteries above 32F. That is what the Volt's TMS does when the Volt is plugged in. Keep in mind that the ~500lb battery in the Volt and the ~900lb in the Bolt represent huge thermal masses that will retain their heat for many hours even if the vehicle is not powered on or plugged in.
 

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The Volt's battery is insulated and it won't be parked for more than probably 14 hours at a time. The car is designed to handle low temp situations. The engine may start just to warm the battery in some extreme cases, but I really don't think you have anything to worry about in terms of damage. These cars were tested in more extreme places like Alaska.

But if running an extension cord from the house is an option, then that seems like a reasonable idea. Just heed the best practices for safety. The manual says not to use an extension cord, so make sure your connections are all excellent and check for any heat build up. Or you could park the Volt close enough to the house to directly plug in there with no extension cord. You will get your charge and the battery will be at optimum temperature. You can even precondition more efficiently.
 

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The Volt's battery is insulated and it won't be parked for more than probably 14 hours at a time. The car is designed to handle low temp situations. The engine may start just to warm the battery in some extreme cases, but I really don't think you have anything to worry about in terms of damage. These cars were tested in more extreme places like Alaska.

But if running an extension cord from the house is an option, then that seems like a reasonable idea. Just heed the best practices for safety. The manual says not to use an extension cord, so make sure your connections are all excellent and check for any heat build up. Or you could park the Volt close enough to the house to directly plug in there with no extension cord. You will get your charge and the battery will be at optimum temperature. You can even precondition more efficiently.
I believe is has been shown through disassembly that the Volt's battery pack has no special insulation, just the packaging of the battery cells and the housing that is designed to circulate coolant around the battery. The Volt's battery maintains its temperature for extended periods due to its large (500lb) thermal mass.

The Volt's gas engine is never used to warm the battery. The Volt heats the battery pack, as required, using an electric heating element within the battery coolant loop, drawing power from the battery. When the gas engine is running either because of ERDTT or because the Volt is in Hold or Mountain mode the waste heat can be used to heat the passenger cabin.
 

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...

The Volt's gas engine is never used to warm the battery. The Volt heats the battery pack, as required, using an electric heating element within the battery coolant loop, drawing power from the battery. When the gas engine is running either because of ERDTT or because the Volt is in Hold or Mountain mode the waste heat can be used to heat the passenger cabin.
I have read on this forum that there is a special mode that the Volt can go into if cold soaked in extreme cold weather where the engine will run and provide all of the drive energy even though the battery has a charge and hold mode has not been selected. This is not the same as ERDTT. This continues for a while then eventually transitions into normal ERDTT mode. Presumably after the battery has warmed up enough to be used for driving power. This is what I was referring to. This was documented by one of our Canadian members, but I don't think it is well documented in the manual. I think the battery has to get very cold, something like below 5 degrees F, for this to happen. Which means weather colder than that for an extended period of time with the car sitting a long time without having been driven or plugged in.
 

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I live in Quebec city,
I experienced this (with my GEN1 MY2013), the car was at insanely cold temperature for the day at work, unplugged. When I left, started the car and engine started immediately and it took maybe 5 to 10 minutes to see the battery come back again on the DIC when the car warmed up a bit (battery was gray with 0 miles left even if I knew the battery wasn't empty). After the 5/10 minutes warmup the car resumed to normal behaviour and the battery had the same charge level when I parked at work in the morning. It surprised me the first time it happened but I think it happened one or two more time that winter. I never experienced this with my GEN2 so far but this usually happends in extreme cold condition only and these are rare situations.
I won't be too worried about letting the car unplugged in Massachusetts where the temperature is never as cold as in QC.
 

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As a fellow New Englander, I think your Volt will be fine in your detached garage over the weekend. It is a quite rare occurrence that the temps get low enough to worry about your battery. Besides, while your wife's Bolt is charging, it will be giving off some heat and I suspect it will rarely go below 30 degrees F in the garage.
 

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I have read on this forum that there is a special mode that the Volt can go into if cold soaked in extreme cold weather where the engine will run and provide all of the drive energy even though the battery has a charge and hold mode has not been selected. This is not the same as ERDTT. This continues for a while then eventually transitions into normal ERDTT mode. Presumably after the battery has warmed up enough to be used for driving power. This is what I was referring to. This was documented by one of our Canadian members, but I don't think it is well documented in the manual. I think the battery has to get very cold, something like below 5 degrees F, for this to happen. Which means weather colder than that for an extended period of time with the car sitting a long time without having been driven or plugged in.
We are saying the same thing. In extreme cold the engine will run as you describe, also in a later post on this thread by a Volt owner in QC, this powers the wheels. The only mechanism the Volt's TMS has for heating the battery is the electric heating element in the battery coolant loop. The Volt has no means of routing waste heat from the gas engine to warm the battery, only for heating the cabin via the cabin heat exchanger. The Volt's high voltage battery pack may be too cold to provide enough power to drive the electric motor(s) but even when cold the battery can provide enough power (up to an undetermined number of kW but not more than 9kW) to warm itself enough to be able to power the electric drive. It is possible that in the most extreme cold conditions the battery would not be able to warm itself, then the Volt would have to be plugged in for a period of time for the TMS to sufficiently warm the battery.
 

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We are saying the same thing. In extreme cold the engine will run as you describe, also in a later post on this thread by a Volt owner in QC, this powers the wheels. The only mechanism the Volt's TMS has for heating the battery is the electric heating element in the battery coolant loop. The Volt has no means of routing waste heat from the gas engine to warm the battery, only for heating the cabin via the cabin heat exchanger. The Volt's high voltage battery pack may be too cold to provide enough power to drive the electric motor(s) but even when cold the battery can provide enough power (up to an undetermined number of kW but not more than 9kW) to warm itself enough to be able to power the electric drive. It is possible that in the most extreme cold conditions the battery would not be able to warm itself, then the Volt would have to be plugged in for a period of time for the TMS to sufficiently warm the battery.
I have no information on how the Bolt would handle this same situation but I suspect that if the Bolt was parked for an extended period in very cold temperatures and not plugged in, when the Bolt was started, if the Bolt's battery was too cold to be driven the Bolt's TMS would use the battery coolant loop's electric heating element to warm up the battery. I imagine the Bolt would display a message on the driver information console such as "Battery thermal conditioning, wait to drive." I don't know the answer but it raises an interesting question for how the Bolt operates in extreme cold.
 

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... The car is designed to handle low temp situations. The engine may start just to warm the battery in some extreme cases, but I really don't think you have anything to worry about in terms of damage. ...
Say What???
I never heard of this and it sounds like a recipe for disaster in an attached garage....:(
 

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Say What???
I never heard of this and it sounds like a recipe for disaster in an attached garage....:(
I was not trying to imply that the Volt would start up by itsself while it is parked. I was referring to to a driving mode more fully explained in later posts in this thread.
 

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Discussion Starter #17
Wow, lots of excellent information. Thanks everyone.

From the sounds of it, I would be better off leaving the Bolt plugged in, even if not charging, and the Volt unplugged if I had to choose between one car or the other.

At least the Volt has the gas engine as a back up so in extreme weather, it could still be driven whereas the Bolt would sit until plugged in long enough to warm the battery to operating temperature. Do I have that correct?
 

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We are saying the same thing. In extreme cold the engine will run as you describe, also in a later post on this thread by a Volt owner in QC, this powers the wheels. The only mechanism the Volt's TMS has for heating the battery is the electric heating element in the battery coolant loop. The Volt has no means of routing waste heat from the gas engine to warm the battery, only for heating the cabin via the cabin heat exchanger. The Volt's high voltage battery pack may be too cold to provide enough power to drive the electric motor(s) but even when cold the battery can provide enough power (up to an undetermined number of kW but not more than 9kW) to warm itself enough to be able to power the electric drive. It is possible that in the most extreme cold conditions the battery would not be able to warm itself, then the Volt would have to be plugged in for a period of time for the TMS to sufficiently warm the battery.
I agree that the battery is warmed via an electric heating element. My assumption is that if the gas generator is running to provide the driving energy, in order to spare the cold battery that duty, then the gas generator is also probably the source of the energy to the electric heating element. But of course this detail is likely hidden to all but GM engineers.

It is an interesting point, though, regarding how the Bolt might handle the same situation, as you mentioned. Obviously the Bolt would be restricted to using battery power or being plugged in.
 

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I agree that the battery is warmed via an electric heating element. My assumption is that if the gas generator is running to provide the driving energy, in order to spare the cold battery that duty, then the gas generator is also probably the source of the energy to the electric heating element. But of course this detail is likely hidden to all but GM engineers.

It is an interesting point, though, regarding how the Bolt might handle the same situation, as you mentioned. Obviously the Bolt would be restricted to using battery power or being plugged in.
Normally if the gas engine is running some of gas engine output drives the wheels and engine output is also used to spin MGA to generate electricity to power MGB. Any excess power generated would be sent to the battery. If the Volt's battery is too cold to power the vehicle it would also be too cold to charge so there would be nowhere to route the excess power being generated, at least until the battery warmed up. The Volt always draws power from the battery when heating or cooling the battery (via the electric heating element or the AC unit.) If the Volt was parked, plugged in the TMS would warm the battery as needed using power from the battery. The Volt would sense the power being drawn from the battery and the on-board battery charger would be switched on to replenish, top off the battery.
 

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Wow, lots of excellent information. Thanks everyone.

From the sounds of it, I would be better off leaving the Bolt plugged in, even if not charging, and the Volt unplugged if I had to choose between one car or the other.

At least the Volt has the gas engine as a back up so in extreme weather, it could still be driven whereas the Bolt would sit until plugged in long enough to warm the battery to operating temperature. Do I have that correct?
Yes, absoluletly. Bolt has no "backup plan" so keeping it plugged when you can is the best way to go. Don't worry about damages due to the cold on both cars, they will survive winter easily.

By the way, nice avatar! Go Bruins!
 
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