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Discussion Starter #1 (Edited)
My 2015 Nissan Leaf survived 3 Midcoast Maine winters in fine shape with
no indication of battery degradation (22,000 miles). The word then was
don't charge to 100% unless the car will be used relatively soon. This
raised the question, why not do the same with the Bolt.

Experiment #1 . Leave the L1 plugged in (Hill top on) and measure kW
expressed as cost per dayfor the electricity along with garage
temperature for a few days.
26F $1.97 31F $1.07 34F $1.08 44F $1.08
(Significant but ok if battery helped)

Experiment #2 . Unplug the L2 and measure kW over about 12 hours for
various days.
22F .1Kw 23F .1Kw 27F 0kW 27F 0kW 29F 0kW
(Insignificant current from battery)

Conclusion: At least at this latitude don't leave power plugged
in in cold weather and save a few $$.

A friend with a Volt did one example of each of the above and
seemed to agree with the above conclusion.

Does anyone see anything wrong with the conclusion?
 

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Cold (in the temperature ranges you are talking about) won't cause battery degradation. Capacity may be temporarily reduced, but no degradation.
Heat is one of the main components that results in actual degradation (permanent loss of capacity), so AZ summers are an issue, not NE winters.

Performance of the battery in extreme cold will be impacted, and at some point the BMS will limit draw and performance. At even colder temps it will refuse to let you operate the car until the pack warms.
 

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So plug the car in an hour before you plan on leaving, and "remote start" the vehicle 5 minutes before departure so that the interior is warmer than the garage. Reduce your kWh consumption, and save a few trees.
 

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Conclusion: At least at this latitude don't leave power plugged
in in cold weather and save a few $$.

A friend with a Volt did one example of each of the above and
seemed to agree with the above conclusion.

Does anyone see anything wrong with the conclusion?
When left unplugged in cold weather, after starting the vehicle I've seen a big kick-up in kWh usage as the battery gets conditioned amongst other things. It seems to be a much bigger initial usage as compared to a plugged-in Bolt where battery is already kept conditioned (kept around 40F as I understand it). I don't have any data to prove this. But IMO there's some "payback" to be made against what looks like savings by leaving vehicle unplugged. Don't know what the breakeven point might be.
 

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When left unplugged in cold weather, after starting the vehicle I've seen a big kick-up in kWh usage as the battery gets conditioned amongst other things. It seems to be a much bigger initial usage as compared to a plugged-in Bolt where battery is already kept conditioned (kept around 40F as I understand it). I don't have any data to prove this. But IMO there's some "payback" to be made against what looks like savings by leaving vehicle unplugged. Don't know what the breakeven point might be.
I prefer to leave my car mostly unplugged. I wonder what the power consumption would be over 30 days where the average temperature is 10 degrees?

This is one thing that caught me off guard. I never thought about the Bolt consuming power to keep the battery warm but I've seen 6% a day, which is around $.40 and about $12 for a month. I'm sure people that are way up north have seen larger numbers. It's not much in the grand scheme of things but seems pricey for the Bolt to sit there and do nothing.
 

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I prefer to leave my car mostly unplugged. I wonder what the power consumption would be over 30 days where the average temperature is 10 degrees?

This is one thing that caught me off guard. I never thought about the Bolt consuming power to keep the battery warm but I've seen 6% a day, which is around $.40 and about $12 for a month. I'm sure people that are way up north have seen larger numbers. It's not much in the grand scheme of things but seems pricey for the Bolt to sit there and do nothing.
My Bolt was idle during the first half of January for 439 hours (over 18 consecutive days). Average temperature (in garage) over those days was -6C/21F. Ranging 24 hr daily averages from low= -14C/8F to high 7C/44F.

Used 106 kWh's at the EVSE for battery conditioning over those 18 days. Total cost here= $11.

To me, well worth it in order to suppress paranoia of frozen battery. Which won't happen with Bolt's LI-ion I guess but I've had to deal with it with conventional lead-acid batteries and it ain't pretty.

Unplugged sitting in extreme cold (minus F's) there's a little evidence in other threads that unplugged batt cond usage can be up in the area of 7 kWh/day. But that cuts back apparently when battery hits 30% SOC and lower. Don't know how long at what temp sitting unplugged, the battery becomes inoperative. There should have been more put in Bolt owner's manual specifically about this.
 

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Don't know how long at what temp sitting unplugged, the battery becomes inoperative. There should have been more put in Bolt owner's manual specifically about this.
Agreed. We're having to figure it out ourselves and there's no doubt most dealers wouldn't have a clue.
 

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Boba- Would be better to get the actual kWh consumed rather than cost, since that is a variable depending on location. Good data otherwise.

I'm surprised the consumption is as much as it is with the car being in a garage. I wouldn't be ok with an undriven car costing $1/day in "fuel".

there's some "payback" to be made against what looks like savings by leaving vehicle unplugged. Don't know what the breakeven point might be.
Heat attempts to reach an equilibrium with the surrounding environment. The greater the difference in temperature, the greater the transfer of heat. What this means is that it will always take more energy to keep something warm (bigger heat difference) than to allow it to cool off (smaller heat difference) until it is needed to be warmed.

So, even though it takes a higher amount of energy to heat something that has cooled off, the total consumed energy will always be less than if you had kept it warm the entire time.

This certainly applies to heating/cooling the home, where it is always more efficient to turn off the heater/cooler when you leave the house than to leave it running while you are gone.

Unplugged sitting in extreme cold (minus F's) there's a little evidence in other threads that unplugged batt cond usage can be up in the area of 7 kWh/day. But that cuts back apparently when battery hits 30% SOC and lower. Don't know how long at what temp sitting unplugged, the battery becomes inoperative. There should have been more put in Bolt owner's manual specifically about this.
My understanding was that traction battery consumption was eliminated altogether when it went below 30% SOC (correct me if wrong). I would expect the 12v battery to go flat long before the traction battery died, possibly years sooner given Li-ion low self-discharge rate at low SOC. That Canadian hockey guy on this forum went below 30% SOC and then attempted to DCFC in -20 weather, and it wasn't possible because the battery temp went below some threshold (still trying to find out what that is) and DCFC is incapable of conditioning the battery before charging it.
 

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Bolt owner's manual doesn't help ?

Page 204
“Parking the vehicle in extreme cold
for several days without the charge
cord connected may cause the
vehicle not to start. The vehicle will
need to be plugged in to allow the
high voltage battery to be warmed
sufficiently.”


Suggests that there might be threshold battery temperature under which the high voltage battery says: “nope we ain’t goin nowhere”. Don’t know if/when the high voltage battery stops recharging the 12v AGM battery. If below 30% SOC there’s no more automatic battery conditioning, then what other draws would be on the 12v ? AGM’s do fairly well in cold and don’t discharge very quickly on their own.

Page 231
“It is recommended that
the vehicle be plugged in when
temperatures are below 0 °C (32 °F)
and above 32 °C (90 °F) to
maximize high voltage battery life.”


In another thread GM engineers indicated charging to 100% full is not detrimental to battery life. Although some think that may be a bit of an overstatement. This paragraph on page 231 makes specific reference to battery life. Below freezing 32F isn’t very cold in context of this winter’s temperature swings. And 32F isn’t far off the belief that 40F is Bolt’s cold weather battery conditioning target. Why does this paragraph make reference to battery life ?
 

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It's probably not beneficial to sales for GM to disclose the heavy power usage in cold weather, whether it be battery conditioning while doing nothing or how much of a hit the range takes when heating the cabin.
 

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I follow the manual’s recommendation and only keep the Bolt plugged in when temperature in my attached garage dips below 32f.

Even though it’s been a pretty cold winter I’ve only had a few days or nights when the garage temp has gotten that low. It’s usually at least 10-15 degrees above the outside temp.

In cold weather I do plug in the car before departing, and use the precondition feature for about 10-15 minutes. Not sure if that’s enough time to bring the battery fully up to operating temperature, but the cabin is nice and toasty. Once underway I drop the cabin temp a few degrees which minimizes battery drain, at least for a portion of each ride.
 

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I prefer to leave my car mostly unplugged. I wonder what the power consumption would be over 30 days where the average temperature is 10 degrees?

This is one thing that caught me off guard. I never thought about the Bolt consuming power to keep the battery warm but I've seen 6% a day, which is around $.40 and about $12 for a month. I'm sure people that are way up north have seen larger numbers. It's not much in the grand scheme of things but seems pricey for the Bolt to sit there and do nothing.
So, the LEAF owners have no battery temperature management and get nearly zero standby loss.

Bolt owners get all the advantages of temperature management, like repeated DCFC in hot weather, better winter range, better longevity, etc. But at the cost of energy losses for battery conditioning. No free lunch.

I would actually like the car to be more aggressive heating the battery in cold weather road trips...so that it would DCFC at the normal rate. Perhaps a user selectable 'road trip' mode when you want to maximize DCFC speed.
 

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Perhaps a user selectable 'road trip' mode when you want to maximize DCFC speed.
Yes, this is one thing I wish the Bolt had. I should never need to use DCFC except in an emergency so I'd prefer to keep the battery temp at the absolute minimum for propulsion power so money isn't wasted heating the battery. However, if I regularly used DCFC, I'd want the battery temp at a point where it can consume the most amount of power. Seems like such a simple concept.

Then again, Chevy couldn't even offer adjustable sun visors........
 
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