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Discussion Starter #1
There's not much info about battery conditioning in the owner's manual. Can anybody answer the following questions:

1. Is it in any way dependent on the state of charge of the battery?

2. What battery temperature range does the system try to maintain, both when plugged in and unplugged?

3. How many peak watts does the system apply to battery heating and cooling, both when the car is plugged in and unplugged?
 

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There's not much info about battery conditioning in the owner's manual. Can anybody answer the following questions:

1. Is it in any way dependent on the state of charge of the battery?

2. What battery temperature range does the system try to maintain, both when plugged in and unplugged?

3. How many peak watts does the system apply to battery heating and cooling, both when the car is plugged in and unplugged?
Based on my casual. observations:

1. Not that I've seen.
2. Plugged in: ~60 F on the low end and ~90 F on the high end. Not plugged in: ~40 F on the low end and ~95 to 100 F on the high end.
3. That is not dependent on whether it's plugged in or not plugged in as far as I've observed. In both cases, it's ~ 3 kW. The Bolt EV has a separate battery heater, but it shares the cabin AC system.

(For those who have tracked the data more, please chime in and correct or add any precision to the above.)
 

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When you say "both cases", do you mean both plugged and unplugged, or both heating and cooling?
Both when plugged in/unplugged. The battery heater is ~3 kW. The AC system is the AC system. It might draw as much as 5 to 6 kW, but I can't remember the exact specifications.
 

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The high voltage (HV) traction battery {RESS = rechargeable energy storage system} and cabin A/C share the same HV compressor {ACCM = air conditioning compressor module} but have two separate "refrigerant" loops. The cabin refrigerant loop does not need a separate "coolant loop" since it cools the air directly. The battery refrigerant loop cools fluid in a "coolant loop" through the battery and back. The high voltage 2kW (if John Kelly is correct - it is not 3kW) battery heater {RESSH} uses the same "battery coolant loop" as cooling does. The cabin heater {HCH = heater coolant heater} is a separate HV module {under-hood passenger side wall} and has its own "'coolant loop" (which is used for heating in this case). The third coolant loop is the power electronics (PE) coolant loop (motor, SPIM, OBCM & APM). One loop can handle these 4 components since the OBCM (on-board charging module) cannot be active at the same time as the SPIM (single power inverter module) and the motor. [c.f. Weber Automotive YouTube Channel: "Chevrolet Bolt EV High Voltage Components" (12-5-18) and "Chevy Bolt EV Coolant System Loops" (12-11-18)]
 

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Discussion Starter #6
The AC system is the AC system. It might draw as much as 5 to 6 kW, but I can't remember the exact specifications.
When I turn on the cabin AC, I see on the DIC that it draws about 1kw. Does it take a lot more energy to circulate coolant than air?
 

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When I turn on the cabin AC, I see on the DIC that it draws about 1kw. Does it take a lot more energy to circulate coolant than air?
Is that on Max LO setting? The Bolt EV's climate control system will only draw as much energy as is needed to maintain the set temperature. If the cabin is close to the set temperature, it will hardly draw any power at all.
 

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Discussion Starter #8
Is that on Max LO setting? The Bolt EV's climate control system will only draw as much energy as is needed to maintain the set temperature. If the cabin is close to the set temperature, it will hardly draw any power at all.
I don't know what Max LO setting is. I'm driving a 2019 LT. But true, I have not yet used the AC in really hot weather. I started driving the car last October.

Somewhere I read that when the car is unplugged, the car won't condition the battery if its SOC is less than 30%. Could there be any truth to that?
 

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I don't know what Max LO setting is. I'm driving a 2019 LT. But true, I have not yet used the AC in really hot weather. I started driving the car last October.

Somewhere I read that when the car is unplugged, the car won't condition the battery if its SOC is less than 30%. Could there be any truth to that?
For LO, you have to turn the climate control system on auto, and turn the dial all the way to the left (lowest possible temperature setting). It should turn the AC on to max power.

As for not running battery conditioning when the car is unplugged and less than 30% battery, that makes sense to me. You wouldn't want to drain your battery completely. It's not going to get damaged by any temperatures that it's likely to encounter just sitting there.
 

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The high voltage (HV) traction battery {RESS = rechargeable energy storage system} and cabin A/C share the same HV compressor {ACCM = air conditioning compressor module} but have two separate "refrigerant" loops. The cabin refrigerant loop does not need a separate "coolant loop" since it cools the air directly. The battery refrigerant loop cools fluid in a "coolant loop" through the battery and back. The high voltage 2kW (if John Kelly is correct - it is not 3kW) battery heater {RESSH} uses the same "battery coolant loop" as cooling does. The cabin heater {HCH = heater coolant heater} is a separate HV module {under-hood passenger side wall} and has its own "'coolant loop" (which is used for heating in this case). The third coolant loop is the power electronics (PE) coolant loop (motor, SPIM, OBCM & APM). One loop can handle these 4 components since the OBCM (on-board charging module) cannot be active at the same time as the SPIM (single power inverter module) and the motor. [c.f. Weber Automotive YouTube Channel: "Chevrolet Bolt EV High Voltage Components" (12-5-18) and "Chevy Bolt EV Coolant System Loops" (12-11-18)]
I just bought a Juicebox 40pro. I set it to stop charging at 75%...But my fear is this: I park in a hot garage in phoenix and wonder "if the juicebox shuts-down when the battery reaches 75%, would the CAR assume that it is NOT PLUGGED-IN, therefore, NOT turn-on the "battery cooling" that it would normally do, if it thought it needed it to cool the battery. So, I'm trying to create a situation that keeps the battery healthier by only charging to 75%, but may be doing more harm, because the car might think it's not plugged-in, and not turn on the battery cooling, when it would be beneficial. I think the juicebox turns off, as if a circuit breaker is tripped. and car won't realize that it IS plugged-in. What do you think??
 

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So why not just set the car to charge to 75% and leave it plugged in at all times? Or if you have a earlier model Bolt, set the Bolt to Hilltop reserve?

Since the car is smart in terms of its charging, seems better to leave the EVSE simple and program the car.

ga2500ev
 

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The high voltage (HV) traction battery {RESS = rechargeable energy storage system} and cabin A/C share the same HV compressor {ACCM = air conditioning compressor module} but have two separate "refrigerant" loops. The cabin refrigerant loop does not need a separate "coolant loop" since it cools the air directly. The battery refrigerant loop cools fluid in a "coolant loop" through the battery and back. The high voltage 2kW (if John Kelly is correct - it is not 3kW) battery heater {RESSH} uses the same "battery coolant loop" as cooling does. The cabin heater {HCH = heater coolant heater} is a separate HV module {under-hood passenger side wall} and has its own "'coolant loop" (which is used for heating in this case). The third coolant loop is the power electronics (PE) coolant loop (motor, SPIM, OBCM & APM). One loop can handle these 4 components since the OBCM (on-board charging module) cannot be active at the same time as the SPIM (single power inverter module) and the motor. [c.f. Weber Automotive YouTube Channel: "Chevrolet Bolt EV High Voltage Components" (12-5-18) and "Chevy Bolt EV Coolant System Loops" (12-11-18)]
I just saw this post. Yes, the battery heater and chiller both work by heating liquid, so while the Bolt EV uses the AC to cool the battery, it's not functioning in the same way as it does when it's cooling the cabin. I would expect that the power draw is the same, though there might be additional losses with the liquid cooling system.

As for the heater, I would say that it needs to be at least 2 kW. According to my Torque Pro readings, I've seen as high as 2,700 to 2,800 W being drawn by the battery heater, so unless it is accounting for some other energy draw, the heater has to be rated for more than 2 kW.
 

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As for the heater, I would say that it needs to be at least 2 kW. According to my Torque Pro readings, I've seen as high as 2,700 to 2,800 W being drawn by the battery heater, so unless it is accounting for some other energy draw, the heater has to be rated for more than 2 kW.
Each of the three coolant loops has a surge tank and a pump, in addition to the components in the loop. Whenever the "request" for cooling or heating "arrives", the pump, as well as the component is activated. Perhaps (as I do not know for sure) the wattage used by the pump is added to the 'nominal' 2 kW of the RESSH to produce a higher reading on the Torque Pro.
 

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Now that's confusing. Please explain how a chiller works by heating liquid.
Is "heat" being used in a generic sense? It depends on the direction of the flow of the heat energy, much as I used "negative acceleration" for "deceleration" when I taught physics.
 

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Now that's confusing. Please explain how a chiller works by heating liquid.
His intention is to say that the battery is both heated and cooled by using liquid as a heat transfer medium. In one case a heater heats the liquid and its heat content is transferred to the battery. In the other case the battery heats the liquid and its heat content is transferred to the chiller.
 

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Now that's confusing. Please explain how a chiller works by heating liquid.
Yes, I should have been more clear and precise. Both the battery chiller and battery heater condition the battery through liquid. There's no airflow into the battery, so the liquid is either chilled or heated (depending on which is needed) and then pumped through the battery.
 

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Each of the three coolant loops has a surge tank and a pump, in addition to the components in the loop. Whenever the "request" for cooling or heating "arrives", the pump, as well as the component is activated. Perhaps (as I do not know for sure) the wattage used by the pump is added to the 'nominal' 2 kW of the RESSH to produce a higher reading on the Torque Pro.
Yes, that could be it. I have no reference to tell whether 700 to 800 watts makes sense for the energy required to pump coolant, though it could be right. Pumping liquid is fairly energy intensive.
 

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Discussion Starter #19
Professor Kelly at Weber State says the answers are as follows:

1. No.

2. Plugged in, ~65-70 degrees F (18.3-21.1 C). Unplugged with car on, same temperatures. Unplugged with car off, no temperature controls are used.

3. The battery heater is rated at 2kW max, cabin heater at 7.5kW max, AC compressor is 2.2kW max.
 

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2. Plugged in, ~65-70 degrees F (18.3-21.1 C). Unplugged with car on, same temperatures.
This is incorrect unless those are the new battery conditioning parameters after GM's recent cold weather update. Unplugged and on, the car definitely does not heat the battery past 60 F (tracking my logs, the heater appears to shut off at 40 to 45 F in my Bolt EV), and 60 F also appears to be the cutoff for heating with the battery plugged in.

One of the things I was doing on my recent trip down Highway 395 was attempting to track the Bolt EV's battery charging temperature parameters, so while I wasn't focused on the battery conditioning behavior, I was monitoring temperature and energy consumption. Now, it's possible that the battery heater was continuing to operate after 40 F when I was unplugged, and I simply missed it because I was driving. However, after ~40 minutes driving at highway speeds, I arrived at a DCFC, and the battery was still only 44 F.

But, on that same trip, I arrived at a L2 AC charger with the battery pack close to 60 F. After an hour and a half on L2 AC, the battery was still under 60 F, and I observed no battery heating taking place in the Torque Pro app.

One possible reason for the inconsistency is that I have one of the original Bolt EVs with the v1 battery pack, but I don't believe there were any changes to the battery temperature parameters between v1 and v2 packs.
 
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