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Discussion Starter #1 (Edited)
I had a discussion today on uses/value of Level 1 charging. I mentioned that in addition to: 1) true commuters driving no more than 35-40 miles a day; 2) airport long-term (>72 hours) parking lots; 3) college dormitory students who drive only on weekends and park for 4 days; there was, 4) parking in very cold weather just to keep the battery warm (condition the battery). I was told that Teslas can condition the battery ONLY at 240 or > volts, and that my Bolt was probably the same. I thought that when the battery gets really cold, it can use its own charge to condition or ANY voltage being supplied by being plugged-in. I garage park at home in WV (cold winters, but not many below zero days), so have never experienced cold conditioning. Can we condition at 120VAC or only when Level 2 charging?
 

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As a real world example, I had nothing but the 120v charger for the first week I owned my Bolt; I've since had a level 2 charger installed. When it was on the 120v charger, I heard it conditioning the battery (fans on) several times after being fully charged in the hot garage. I would assume the same thing would happen in the opposite extreme (cold).

Mike
 

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High voltage battery conditioning can be done at 120V per these instructions from the owner's manual:
So, as a Nevadan that just enjoyed 112F today and find it still 101F at 10pm tonight (and well over 90 all day/night in the closed and insulated garage), that will pose an interesting question to GM support engineers...

"Should I really be using the peak/off-peak hours settings if it gets really hot during peak times? Does telling the car not to charge from 1pm to 7pm also preclude it from conditioning the batteries during that time?"

I would hope/presume the answer would be no, but that is a subtle enough question that I probably won't trust the local dealership to accurately answer it. Thoughts?
 

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So, as a Nevadan that just enjoyed 112F today and find it still 101F at 10pm tonight (and well over 90 all day/night in the closed and insulated garage), that will pose an interesting question to GM support engineers...

"Should I really be using the peak/off-peak hours settings if it gets really hot during peak times? Does telling the car not to charge from 1pm to 7pm also preclude it from conditioning the batteries during that time?"

I would hope/presume the answer would be no, but that is a subtle enough question that I probably won't trust the local dealership to accurately answer it. Thoughts?
That's a great question. Purely anecdotal but during the winter, I was never able to catch my Bolt conditioning the battery during the night if using the departure timer (but it would condition at the end of the charge). If set to immediate and plugged in, it would wake up and condition.

Yesterday, I found a way to manually trigger battery cooling. The car was at 60% state of charge. I set the Bolt to charge to 55% (2019 only). I then plugged in and immediately the fans kicked on and started cooling the battery.
 

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I'm trying to figure out under what conditions the car will condition the batteries. I live in the Northeast and my previous EV (Ford Focus) was plugged in all the time with "Charge now" so I didn't have to worry about schedules. In those conditions I heard the car conditioning the batteries numerous times. Typically in the winter since the car is in a detached unheated garage, but even sometime in the summer when we get over 90F.

Now I have the Bolt and typically don't charge but once, sometimes twice a week. Also, my electric company now offers discounts for off hour charging (9PM to 7AM).

So I have two scenarios / questions:

If I use my charger schedule (ChargePoint Home), will it allow the car to condition the batteries off schedule? I doubt it but have posed the question to ChargePoint without response.

If I use the Bolt schedule, will it condition the batteries off schedule? I hope so, but really don't know. I need to know this since the car sometimes will sit a week in below 0F conditions.

A side issue when using the car scheduler is that the charger loses it's frame of reference. When I plug the car in, the car will immediately "check" the charger's capabilities, even off schedule. I'm assuming it does this so that it knows how long it will take to charge the batteries. I can see this in the ChargePoint app where the charging graph goes up immediately to ~7.5 kw and then drops to zero. The charger believes after this brief interaction, the car is fully charged and reports so. Even later, when the car starts charging at 9PM, the charger reports nothing. It's confused. This could easily be fixed with a SW upgrade.
 

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I'm trying to figure out under what conditions the car will condition the batteries. I live in the Northeast and my previous EV (Ford Focus) was plugged in all the time with "Charge now" so I didn't have to worry about schedules. In those conditions I heard the car conditioning the batteries numerous times. Typically in the winter since the car is in a detached unheated garage, but even sometime in the summer when we get over 90F.
Based on my own testing.

1. If the car is plugged in and not charging (either charge complete or charge not needed) the car will periodically wake up and condition the battery to about 27C
2. If the car is not plugged in but turned on and the battery temp is above about 34C the car will cool the battery to about 31C.
3. If the car is not plugged in and not turned on the car will not do anything to cool the battery (I have seen my battery get as hot as 37C, it's possible that the car would actually cool the battery if it got to some temperature hotter than that but I have not observed it)
4. If the car is plugged in and turned on the car will cool the battery to about 27C.

In case 1 (or in case 2 or 4 if the passenger A/C is not turned on) the car will cycle the A/C compressor on and off 2-3 times per minute as it cools the battery.

In case 2 or 4 if the passenger A/C is turned on the A/C compressor runs continuously and also chills the battery coolant temperature to a colder temperature (by about 10C) which would in theory cool the battery faster.

In case 4 the car will cool the battery to about 27C even if the amount of power being provided by the EVSE is less than the amount of power being used to cool the battery. This means if you are getting less than about 3kW from your EVSE you will be cooling your battery partially from battery power and partially from the power provided by the EVSE.

I have it on my list to test whether the behavior in case 4 is the same when plugged into an L1 EVSE but I expect it will be.

I have no data on battery heating because it never gets cold enough here that battery heating would take place.

Edit: also to add if you are using any type of scheduling (either in the EVSE or the car) for charging it does not count as "plugged in" when the car is not allowed to charge.
 

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Yesterday, I found a way to manually trigger battery cooling. The car was at 60% state of charge. I set the Bolt to charge to 55% (2019 only). I then plugged in and immediately the fans kicked on and started cooling the battery.
I found the same thing out last year after I accidentally charged to 100%, when I got home from work I was still above 90% and when I plugged in (with Hill Top Reserve turned back on) the car immediately started a battery cooling cycle without charging the battery.

Obviously this is much more useful for 2019+ Bolt owners because they could just set the target charge level to something below the current SoC and the car will immediately go into battery conditioning mode if it's needed.

If I had Target Charge Level on my car I would leave my car plugged in all the time when I was at home.
 

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Based on my own testing.

3. If the car is not plugged in and not turned on the car will not do anything to cool the battery (I have seen my battery get as hot as 37C, it's possible that the car would actually cool the battery if it got to some temperature hotter than that but I have not observed it)
I don't know what my battery temp was, but while I was at work, the air was at 95F and the car was parked in the sun and unplugged. It had conditioned the battery sometime during the day as when I got in the car, the Energy display showed conditioning. (I was actually pretty happy to see it because it was the first time in my 10 months of ownership that battery conditioning occurred and I was beginning to wonder if something was wrong with the system and preventing it from working.)
 

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Edit: also to add if you are using any type of scheduling (either in the EVSE or the car) for charging it does not count as "plugged in" when the car is not allowed to charge.
So if this is true, I'm amazed at all the charging schemes people have in order to maintain the capacity of the battery. I would think that allowing the car to not condition the battery during extreme temperatures (either hot or cold) would do more damage.

Maybe that is why GM recommends keeping the car plugged in.
 

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So if this is true, I'm amazed at all the charging schemes people have in order to maintain the capacity of the battery. I would think that allowing the car to not condition the battery during extreme temperatures (either hot or cold) would do more damage.

Maybe that is why GM recommends keeping the car plugged in.
Pick your poison, if you keep your 2017 or 2018 Bolt plugged in all the time, it will charge to ~90% (assuming Hill Top Reserve enabled) and stay there, in my case if I plugged in every night it would spend almost it's entire life above 80%, only dropping below that on my occasional longer drives. Heck most of the time it would only drop below 85% on my drive home from work so it would in reality spend ~12 hours per day pegged at ~90%, 10-11 hours between 85% and 90% and 1-2 hours between 80% and 85%.

Combine that with the reality that most people (myself included) do not even have the option to stay plugged in during the hottest parts of the day anyways, so the only time I could leave my car plugged in would be at night when the car wouldn't be conditioning anyways so I'd just be stressing my battery (by charging to and holding a high SoC) for no benefit in terms of keeping the battery cool when it needs to be. Now I could potentially get some benefit on weekends because I almost never drive my Bolt on Saturday or Sunday but since my parking spot at home (unlike at work) is shaded my battery rarely gets hot enough just parked in the shade that it would be cooled if I left it plugged in sitting at 90% SoC all weekend long.

Life would be simpler if I had Target Charge Setting, or even if HTR was at ~75% SoC instead of ~90% (89% on my car).

Also, extreme cold temporarily effects the performance of the battery but it doesn't cause any damage/stress to it like extreme heat (at least not at temperatures the Bolt will ever see).
 

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I don't know what my battery temp was, but while I was at work, the air was at 95F and the car was parked in the sun and unplugged. It had conditioned the battery sometime during the day as when I got in the car, the Energy display showed conditioning. (I was actually pretty happy to see it because it was the first time in my 10 months of ownership that battery conditioning occurred and I was beginning to wonder if something was wrong with the system and preventing it from working.)
See that's interesting, because my battery temp doesn't really get to 35C until ambient temps get over 100F, when I saw my battery at 37C the outside temp was at 108F IIRC.

It's been speculated the car doesn't cool the battery from battery power until the battery gets to 40C, If that's true I don't know how your battery could get to 40C in ~95F ambient temperatures if mine was at 37C in 108F ambient temperature.

Does it cool off at night where you are or does it stay hot all night long? I know even on our hottest days it will cool down to the 70's, even the 60's overnight and the battery passively sheds a good bit of heat over the course of the night and early morning.

On a typical very hot day for me the car will cool the battery to 31C on the drive home, then I plug in for 30 minutes and let mode 4 cool the battery further to 27C. By the time I leave for work in the morning the battery is usually down to about 23C.

Also worth noting there is a 1C-2C difference in my peak battery temperature depending on whether or not I take my car to lunch. If I walk to lunch or ride with someone else my battery will be cooler at the end of the day than if I leave it parked all day long. My belief is that in the hour or so I'm at lunch my parking spot (which had been shaded by my car since morning) soaks up a lot of heat from the sun which it proceeds to radiate up into the battery over the course of the afternoon.
 

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If I use my charger schedule (ChargePoint Home), will it allow the car to condition the batteries off schedule? I doubt it but have posed the question to ChargePoint without response.
I also doubt it. There's nothing in the J1772 protocol to let the EVSE know the reason why the car might want juice and to allow or disallow it based upon the reason.

From looking at https://openev.freshdesk.com/support/solutions/articles/6000052074-basics-of-sae-j1772, I'm guessing that during the times when the EVSE isn't supposed to supply power (due to scheduling), it could set the duty cycle to 0% or set the proximity to not connected and/or just not supply any power, even if the connected vehicle requests it.

ChargePoint folks may not know as they may have no idea what's really going on at the car side, since they don't control it and GM could change what happens on that end.
 

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I'm surprised my Bolt battery pack is at 87.8F. My Leaf battery pack was at 87.6 as well. I would have thought with TMS the Bolt battery back would be able to run cooler than a Leaf's!
 

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There's a phenomenon I've run into with technology from time to time. Sometimes I find myself overthinking how to use or set up a product and end up making it worse in the process. Remember that these vehicles were designed for the masses, most of which will just plug their cars in when they need to, and drive them when they need to. I've set my charge limit to 80% and I just plug it in and leave it plugged in after I drive it. I figure that's how it was designed to work and I'm not going to worry about monitoring temps, optimization schemes, fully discharging the battery from time to time or fully charging it to try to calibrate the GOM. I'm just going to drive it and enjoy it.

Mike
 

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Ah, I'm starting to yearn for the "Good ole days" before cars had computers. Now days, one has to understand how the algorithms work and the programming that goes into the compute chips. We could spend eternity trying to figure that out, since the chips can be incredibly complex. The results are this thread, where we try to guess the logic in the chips. It would be nice if Chevrolet just released the programming. But I'm sure that would be considered "proprietary knowledge".
 

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I'm surprised my Bolt battery pack is at 87.8F. My Leaf battery pack was at 87.6 as well. I would have thought with TMS the Bolt battery back would be able to run cooler than a Leaf's!

The last few days have been our warmest this year, so far. Yesterday we did an 85 mile round trip to a peach orchard. The ambient temp hit the high 90s F. We had the AC on the whole drive, but it didn't encourage the battery to cool, as it does when plugged in. The traction pack sat in the mid 80s F to 91 F max. The motor/gearbox saw 160 F, the battery coolant sensor, which I suspect is located near the battery's tankless heater, between the motor/gearbox and the front of the battery pack, saw 101 F after sitting in the asphalt parking lot.

About ten miles from home, the battery cooling finally kicked in and dropped the battery coolant into the low 60s F. The cooling kicked in again at the end of charging, as it always does in the summer weather.
 

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There's a phenomenon I've run into with technology from time to time. Sometimes I find myself overthinking how to use or set up a product and end up making it worse in the process. Remember that these vehicles were designed for the masses, most of which will just plug their cars in when they need to, and drive them when they need to. I've set my charge limit to 80% and I just plug it in and leave it plugged in after I drive it. I figure that's how it was designed to work and I'm not going to worry about monitoring temps, optimization schemes, fully discharging the battery from time to time or fully charging it to try to calibrate the GOM. I'm just going to drive it and enjoy it.

Mike
I'm with you Mike and believe I will just enjoy the car and not fret over it. My luck I would figure out a scheme that would have the battery fail at 8.5 years just after the warranty expires.

I do have some experience with my previous electric car, the Ford Focus. That car was plugged in every time I came home whether I drove 60 miles that day or 2. The decision is easier when the range is only 75 miles, I get it. But on occasion the car would condition the batteries in the summer, and frequently in the winter. So I don't know which is worse, not conditioning the batteries in extreme temperatures, or keeping it plugged in all the time.

I can tell you that after owning the car for almost 5 years, the last day I drove it to the Chevy dealer, I drove 50 miles that day. When I got to the dealer the GOM read 40 miles left. Of course it was a gorgeous day so no air conditioning needed, but I don't think I lost much capacity in that battery after 5 years.
 
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