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Discussion Starter · #1 ·
Tried this once before and logging stopped after an hour or so.

On that logging session battery temp started at right around freezing, and the battery heater operated until the battery temperature was 35F+ and then shut off.

This time, my battery temp started at 37.4, and battery temperature peaked during the charging phase about 4 hours into the charge at 44.6F, and then started to actually go down as ambient air temperatures dropped further (air temp started at 30F and dropped down to 24F by end of charge) with battery temperature dropping to 41F by the end of the charging phase.

In other words, actual L2 charging does very little to warm the battery when ambient temperatures are below 30ish deg F.

At the end of the charging session, when the battery reached 87.5% SOC (hill top reserve active) the battery heater came on for the next hour raising the battery pack temperature from 41F to 60F at which point it shut off and stopped drawing power from my ChargePoint 32 amp L2 charger.

Now, if you set the Bolt for Time of Departure charging, does it set you up to end charging at your departure time, or end battery pack conditioning at your departure time? I can see getting much better range out of a 60F pack than out of one at 40F or lower...

Keith
 

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If you set the Bolt for Time of Departure charging, does it set you up to end charging at your departure time, or end battery pack conditioning at your departure time? I can see getting much better range out of a 60F pack than out of one at 40F or lower...
In my experience a bit of both. I find that most of the time charging is done five to ten minutes before departure, and so it gets to do a little bit of warming before the departure time.
 

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Discussion Starter · #3 ·
In my experience a bit of both. I find that most of the time charging is done five to ten minutes before departure, and so it gets to do a little bit of warming before the departure time.
So, in my situation with no TOU price plan to worry about, I could set up my departure time an hour before my actual departure time to get the full benefit of a 60F battery pack. I will not change my charging pattern at this point since I am gathering temp vs efficiency data on my daily commute.

I wonder if it uses the battery heater when you do a precondition of the car? I will check my battery pack temp when I leave work this morning (working night shift) and see if the battery is included in preconditioning or if it is only the cabin. Car will have been sitting for 12 hours in 30F ambient, so we will see what battery temp is when I leave. If the battery is NOT warmed, I will repeat the check with the car plugged in to see if it reacts differently.

Keith

PS: I have been gathering temp vs efficiency data on my daily commute... and I don't know what days I preconditioned and what days I didn't... if preconditioning does warm the battery it will definitely throw off my data set a bit, and I will stop using preconditioning to get better "raw" data. If not then I will continue to use the precondition feature.
 

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So, in my situation with no TOU price plan to worry about, I could set up my departure time an hour before my actual departure time to get the full benefit of a 60F battery pack... .

This is what I have started doing for the exact reasons you describe. I had been charging immediately upon returning from work because in the summer my solar panels were still generating some juice when I would normally get home if I didn't bike to work. But in the winter this meant that the battery would be charged in the early evening and the conditioning would raise the battery temps at the end of the charge cycle, and then sitting over night in the cold garage the battery would loose heat before the following morning commute. It would also sometimes do another battery conditioning cycle to warm the battery, which was really just a waste of electricity...


Setting the car up to be finished charging ~30 minutes before I depart for work in the morning gets the battery above 50F, but not quite to the stopping point of 60F (this varies depending on how cold the garage is). But this charging strategy is doing a better job of enabling me to have a warmer and more efficient battery for the morning commute without wasting battery conditioning power. Although even with this strategy the EV efficiency in cold weather sucks. Data and links to pics in this thread: https://www.chevybolt.org/forum/90-...ge-discussion/23497-cold-weather-effects.html
 

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This time, my battery temp started at 37.4, and battery temperature peaked during the charging phase about 4 hours into the charge at 44.6F, and then started to actually go down as ambient air temperatures dropped further (air temp started at 30F and dropped down to 24F by end of charge) with battery temperature dropping to 41F by the end of the charging phase.

Keith
This is making me think that the setup you might want for the Bolt EV is:
  • Immediate charge to 40%
  • Set charging for departure time (1 hour before actual departure)
  • Run two 20-minute preconditioning sessions while you get ready in the morning
  • Do the ICE routine and actually start the Bolt EV about 10 minutes before you leave, running all climate on max while plugged in
 

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This is making me think that the setup you might want for the Bolt EV is:
  • Immediate charge to 40%
  • Set charging for departure time (1 hour before actual departure)
  • Run two 20-minute preconditioning sessions while you get ready in the morning
  • Do the ICE routine and actually start the Bolt EV about 10 minutes before you leave, running all climate on max while plugged in

Sounds like a job for Mr. Arduino or Ms Pi.:nerd:
 
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