Remote recondition source of power?

[Oceanbreeze]

I am hoping someone knows more about the electrical characteristics of the onboard HVAC systems and perhaps explain how they get powered under various scenarios (plugged in and charging, plugged in and fully charged, during regen).

Q1: If the car is plugged into a L2 EVSE, does remote reconditioning (RR) still get powered directly from the battery pack, or off the EVSE/onboard inverter?

Q1a: (And if it's the latter, does the battery charge at a slower rate while RR is running?)

Q2: Since the onboard charger will draw a max of 3.3kW, I've set the L2 EVSE to 16A max. Does the car draw more than 3.3kW when it is charging AND also running RR?

Q3: do the heated front seats run off the 12v battery?

Q4: when does the 12V AGM battery get recharged, and from what power source?

Thank you.

 

[Infinion]

I am hoping someone knows more about the electrical characteristics of the onboard HVAC systems and perhaps explain how they get powered under various scenarios (plugged in and charging, plugged in and fully charged, during regen).

Q1: If the car is plugged into a L2 EVSE, does remote reconditioning (RR) still get powered directly from the battery pack, or off the EVSE/onboard inverter?

Q1a: (And if it's the latter, does the battery charge at a slower rate while RR is running?)

Q2: Since the onboard charger will draw a max of 3.3kW, I've set the L2 EVSE to 16A max. Does the car draw more than 3.3kW when it is charging AND also running RR?

Q3: do the heated front seats run off the 12v battery?

Q4: when does the 12V AGM battery get recharged, and from what power source?

Thank you.

• Q1: Assuming your charge settings are set to "Immediate", then the answer is both. Pre-conditioning will take power from the EVSE until the battery needs to supplement additional power.
  Also, keep in mind that a L2 EVSE is just a relay that closes 240V to the on-board charger. There's no power conversion going on in there. The on-board charger takes this 120/240V AC and turns it into high voltage DC which is fed to the high voltage busbars where it gets used towards either charging or powering the various high voltage loads depending on what is active.
  
  
  
• Q1a: Yes, the Spark EV will pull its 3.3kW limit or the EVSE's limit, whichever comes first. It will not pull additional power for other loads, and as a result, you get less net power provided towards battery charging.
  
  
  
• Q2: No, the 3.3kW is the limit. If your supply sags to 190V, it will not pull more current to reach 3.3kW either. However, if your supply rises to 246-250V, the input current will drop to ~13.5A as to not exceed the power limit.
  
  Even if the EVSE is set to 32A @ 240VAC, the on-board charger is incapable of exceeding 16A because of either the current rating of the cables/connectors, or current limits of the on-board charger's components such as transistors, diodes, or transformer windings that are programmed into the on-board charger's power management controller.
  
  If the load current exceeds the supply current, the on-board charger has no way of exceeding its limits, not even momentarily.
  
  
  
• Q3: No, while the heated seats are connected to the 12V battery, they do not "run" off of the 12V battery. While the car is "ON", in service mode, or during preconditioning from your remote-start key or the MyChevrolet / MyGMC app, the Accessory Power Module will engage and increase this voltage to somewhere between 12.9V-14.5V. In other words, the 12V battery never has power priority unless 12V power exceeds ~2kW (3.6kW fused) which isn't really possible anyway, unless there's some kind of fault or 3rd party accessory like an inverter drinking power. As long as voltage remains above ~12.6V, power comes from the Accessory Power Module, which comes from the High Voltage busbar (See Q4 Fuel Economy Mode for an exception). If the On-board charger is actively making power, then the heated seats are powered by your EVSE. Otherwise, if you are pre-conditioning the vehicle while charging and this exceeds the 3.3kW limit, then the heated seats are supplemented by the high voltage battery.
  
  If you hold the power button on the infotainment screen, you can run the radio off the AGM. Headlights and DRL, brake lights, interior dome light, and all other automotive accessories not locked out by the 'start' button will draw power from the 12V battery, as the APM will be disabled. The AGM is really reserved for closing the contactors in order to initially connect high voltage power for the APM to run continuously. You can try this yourself when you start the car. Watch as the interior dome light makes a marked increase in brightness. This only happens after you hear the high voltage contactors sequentially close.
  
  Also, the heated seats draw somewhere in the range of 20-30W each. This will also turn on during pre-conditioning if the button is in the on position.
  
  This also applies to cabin heat. Pre-conditioning heats the cabin to whatever the current temperature setpoint is. If you don't want to pull more than the EVSE can supply, maintaining a temperature a few degrees below where you like it can be a good idea to reduce the time that the battery is supplementing extra power for. I can't remember if keeping the HVAC button off also keeps it off during pre-conditioning.
  
  
• Q4: The battery charges while the vehicle is in the 'ON' state, or in 'service' mode (hold start button down for 5s). It charges as you drive like any ICE with an an alternator would.
  Also, the APM is responsible for charging.
  
  However, I should say a few things here:
  The AGM bounces between 85% SoC and 100% SoC while on.
  According to the service manual (which you can pick up for $10/year at alldatadiy.com with discount codes) under "Vehicle » Starting and Charging » Charging System » Description and Operation"
  Charging won't kick in until one of the following is true:
  
  Normal Mode:
  - The wipers are ON for more than 3 seconds.
  - GMLAN Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control head. High speed cooling fan, rear defogger and HVAC high speed blower operation can cause the BCM to enter the Charge Mode.
  - The estimated battery temperature is less than 0°C (32°F).
  - Vehicle Speed is greater than 145 km/h (90 mph)
  - Current Sensor Fault Exists
  - System Voltage was determined to be below 12.56 V
  
  If none of these are true, the charging system can enter Fuel Economy Mode, Headlamp Mode, Voltage Reduction Mode, or Battery Sulfation Mode
  
  Headlamp Mode
  The BCM will enter Headlamp Mode whenever the high or low beam headlamps are ON. Voltage will be regulated between 13.9-14.5 V.
  
  
  Fuel Economy Mode
  The BCM will enter Fuel Economy Mode when the ambient air temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is greater than -8 A but less than 5 A, and the battery state of charge is greater than or equal to 85 percent. Its targeted APM set-point voltage is the open circuit voltage of the battery and can be between 12.6-13.2 V. The BCM will exit this mode and enter Normal Mode when any of the conditions described above are present.
  
  Voltage Reduction Mode
  
  The BCM will enter Voltage Reduction Mode when the calculated battery temperature is above 0°C (32°F) and the calculated battery current is greater than -7 A but less than 1 A. Its targeted APM set-point voltage is 12.9-13.2 V. The BCM will exit this mode once the criteria are met for Normal Mode.
  
  If the car isn't started at all for days/weeks, the battery will be tended for up to around 2 months or the battery pack drops to a low SoC, whichever comes first. You can still overdischarge your AGM battery, however. I don't have specifics right now for how the floating algorithm works, but if anyone else wants to chime in, it would be appreciated.

If you pre-condition the car while it is plugged into an L2 EVSE, the car will pull 2.4kW for the battery heater if battery cell temperatures are less than 13ºC. If you had the HVAC on, it will pull up to 7kW of resistive heating until cabin temperature reaches the setpoint and throttles down. This is why it's always a good idea to precondition if you aren't immediately leaving for at least 5-10 mins so the battery has time to recover some lost charge as the loads drop out. Ofcourse, this time is completely arbitrary and depends on the temperature in your area and the temperature set in the vehicle.

 

[Oceanbreeze]

Thank you. I really appreciate the detailed explanation.

 

[NORTON]

This is all great info! Thanks for sharing these details.

I question having to set the car's HVAC settings the night before doing a Precondition.
I thought even if it is all turned off it will heat or cool the cabin to some default, even if the controls were not set.
Except for the seat heat. That button probably needs to be pressed in for seat heat to work.

Frosty morning here. I'll go out and test this....

edit:
28° morning.
Just checked after turning off the HVAC with the car on. Turned on the driver's seat. Powered off the car.
Stepped out and locked it and started a Precondition.
Went back 16 minutes later and the frost on the glass was melted and the interior was warm-ish.
But there was no seat heat that I could feel even though the seat heat switch was lit.
Powered up the car and saw that the rear window defrost came on by itself during the Precondition.

So, you don't have to fiddle with the controls when you leave the car. It will do a Precondition as needed when you command one from the Key Fob.

 

[Oceanbreeze]

I can confirm the same. We rarely need to use HVAC while driving. It only gets used during preconditioning (which IIRC runs for up to 20-25 min) and without the need to have it on before shutting off the car. And yes, it never makes the cabin hot enough, just warm-ish. I'd prefer that it stops after it warms the cabin a little more. Worth trying to set desirable cabin temp before shutting off to see if that also sets the preconditioning set point.

One other thing I haven't figured out yet, preconditioning turns on the marker lights all around. Do they stay on during the entire preconditioning cycle? I noticed mine stay on for 10 min sometimes and maybe more at other times.

 

[SparkE]

Anecdotal evidence here (not from the manual) ...

* I checked the voltage across he 12V "accessory" battery while charging. When charging the Spark EV main (traction) battery, the voltage at the 12V is 13.4V (or 13.6,V I can't remember which). This happens when charging on L1, L2, or DCFC. The same happens when the car is turned on for operation (i.e., driving). So the 12V battery is being charged (if needed) at those times.

* I have gotten in the habit of setting the cabin HVAC controls to 'comfortable' settings when I park the car during the winter. That way, if I need/want to pre-condition the vehicle while plugged in it pulls (most of) the current from the wall and I have a toasty interior when I drive off.

* third - timed charging. (Departure timing). I set the charging to "Departure timing" and set the time of departure to 60-90 minutes LATER than my estimated departure time (because I rarely need a full charge for runs around town). That way the battery is charged to 75-85% of full when I unplug (which rumor has it prolongs the life of the battery, not charging to full ALL THE TIME) and letting the battery sit for hours at a full charge. (I am not sure how this affects "battery conditioning" during winter - i.e., keeping the battery 'warm enough' overnight - it really doesn't get that cold in San Francisco, and preconditioning takes care of that.) When I think I will need a full charge the next day, I simply plug-unplug-plug the L2 and that defaults the car to "immediate charge" (for this one charge session) : see " delayed charge modes can be temporarily overridden to an immediate charge mode for one charge cycle" in the manual, section 5-26. .

 

[Infinion]

This is all great info! Thanks for sharing these details.

I question having to set the car's HVAC settings the night before doing a Precondition.
I thought even if it is all turned off it will heat or cool the cabin to some default, even if the controls were not set.
Except for the seat heat. That button probably needs to be pressed in for seat heat to work.

Frosty morning here. I'll go out and test this....

edit:
28° morning.
Just checked after turning off the HVAC with the car on. Turned on the driver's seat. Powered off the car.
Stepped out and locked it and started a Precondition.
Went back 16 minutes later and the frost on the glass was melted and the interior was warm-ish.
But there was no seat heat that I could feel even though the seat heat switch was lit.
Powered up the car and saw that the rear window defrost came on by itself during the Precondition.

So, you don't have to fiddle with the controls when you leave the car. It will do a Precondition as needed when you command one from the Key Fob.

Thanks for testing this, fantastic! Haha, yeah, you'd think that 7kW would heat the cabin fully by 16 minutes. There's a good chance it could be throttling early as the cabin temp sensor gets closer to the setpoint, so in that case, you could crank it a few degrees higher to keep it at peak power.

That being said, summer preconditioning is much better. I think the A/C compressor is rated for around 6kW at full power (and 30A fused on HV bus), and though I don't know the COP, it's absolutely going to be higher than 2. It uses R-1234yf refrigerant which is the comparable but far more environmentally sustainable refrigerant compared to R-134a by probably 300x (breaks down in 11d vs 10y in atmo), with ~10%-15% drop in performance. Anyway, at a very conservative COP of 2, it should be able to reject 12kW of heat (ignoring compressor efficiency) from the cabin at full blower speed, and should pre-condition way faster than a heater core at COP 1 and 7kW.

Went back 16 minutes later ... But there was no seat heat that I could feel even though the seat heat switch was lit.

No seat heat after 16 minutes is very strange, especially when the button is illuminated... Does it heat up at all, normally?

Yeah, I just checked the circuit diagram and if the LED is illuminated then the seats are energized because they're connected in parallel.

I can confirm the same. We rarely need to use HVAC while driving. It only gets used during preconditioning (which IIRC runs for up to 20-25 min) and without the need to have it on before shutting off the car. And yes, it never makes the cabin hot enough, just warm-ish. I'd prefer that it stops after it warms the cabin a little more. Worth trying to set desirable cabin temp before shutting off to see if that also sets the preconditioning set point.

One other thing I haven't figured out yet, preconditioning turns on the marker lights all around. Do they stay on during the entire preconditioning cycle? I noticed mine stay on for 10 min sometimes and maybe more at other times.

If you're referring to the brake lights and daytime running lights, then yeah, they stay on as long as the car is preconditioning, which is also powered by the EVSE, lol. Also, if you try terminating a pre-condition, those lights should go off.

 

[NORTON]

Thanks again for all the detailed info!
On second thought, with the driver's seat heat switch lit during the precondition, maybe I did not sit there long enough to feel the heat come through.
It was in the low 20's and I had jeans and liners on.
It works normally. I'll leave that switch on before I shut down the car for the night from now on.

 

[SparkE]

Thanks for testing this, fantastic! Haha, yeah, you'd think that 7kW would heat the cabin fully by 16 minutes. There's a good chance it could be throttling early as the cabin temp sensor gets closer to the setpoint, so in that case, you could crank it a few degrees higher to keep it at peak power.

.
To be really clear, that is a max of 7 kW being *used*, only a tad over 3 kW of which is coming from the wall (if the car is plugged in for charging using a L2 charging cable ).

It seems to me (anecdotal) that the heater draws less than 7 kW pretty soon after heating starts. Say, pulls 6-7 kW at the beginning, then drops to 3-4 kW after the resistance elements heat up (3-5 minutes? around SF Bay Area - if in WA state, temps around 20F all night long, it would probably pull 7 kW for a longer amount of time).

As Infinion said, when pre-conditioning leave some (post pre-conditioning) time for the battery to "recover" some of the energy used to heat/cool the vehicle. ( "This is why it's always a good idea to precondition if you aren't immediately leaving for at least 5-10 mins so the battery has time to recover some lost charge as the loads drop out. Of course, this time is completely arbitrary and depends on the temperature in your area and the temperature set in the vehicle." )

 

[NORTON]

.... Of course, this time is completely arbitrary and depends on the temperature in your area and the temperature set in the vehicle[/i]." )

But then, if the HVAC system was set to OFF when you last powered down the Spark EV, it will still heat or cool as required to a default temp, correct?
It may not use the temp setting on the HVAC controls for a Precondition.
More testing ....
You could test setting different fan speeds. That would be an easy to confirm test.

But then, it works either way. I don't care

 

[Oceanbreeze]

Reading about how preconditioning may draw power from both the EVSE and HV battery, I am wondering if that plays a role in how the GOM estimates range after a full charge.

In the summer a full charge showed a range estimate of 95-105 (which I take with a grain of salt). Since we started using preconditioning (and sometimes HVAC while driving), at full charge it shows about 75-85m of range. I am not worried about battery degradation and suspect this is related to the increase in non-traction loads.

Does anyone have a good grasp of the GOM algo as far as range is concerned.

I usually reset the trip odo after a full charge.

Merry Christmasto all Spark EVs.

 

[MrDRMorgan]

Basically, anything in the vehicle that draws power will, to some degree, affect the GOM number. Fo instance, my latest GOM number in my 2014 Spark EV is about 3.5 miles / kWh. I have the heater set to 73 degrees, and the fan speed to 2 and the headlights are turned on. Same thing goes when I use the A/C only it is not quite so bad. If you have access to TorquePro, you can get the capacity number in kWh for the HV battery. The HV battery does degrade but slowly. The GOM is a variable miles /kWh value depending on how you are driving and what accessories you are using at the time. For instance, if you were at Echo Summit near South Lake Tahoe. and were driving downhill to Folsom, you would see a fantastic mi/kWh number for GOM.

I would pay more attention to the Torque Pro value for your HV battery capacity. If you do not have access to TorquePro, try using the information displayed on the energy information screen in the car and calculate the HV battery capacity. It will not be as accurate as the TorquePro value, but it will give you a reasonable estimate.

 

[Oceanbreeze]

Hmmm, I am relatively new here but I am using the term GOM to describe the range min and max on the battery bars on the left.

I am a fairly clear on the trip mileage (miles/kWh), and generally I am not surprised by those -- they seem to be actuals, rather than estimates. FWIW, with my driving style I usually get 5.4-7.5 mi/kWh in town, and I am okay with that calculation including heat loads, etc.

 

[NORTON]

Hmmm, I am relatively new here but I am using the term GOM to describe the range min and max on the battery bars on the left.

.. I usually get 5.4-7.5 mi/kWh in town, ...

The Guess-O-Meter is the main number displayed on the left. It also has a guess at the max and min.

It's a guess at your range by looking at how you previously drove the car.
It has no way of knowing if you are loading up the car with your heavy In-Laws and heading up a mountain with the heat working hard.

And it had trend lines that show which side of the GOM you are trending to, min or max.
It's nice data to see, but limited on this short range EV.

Now, on a cross country trek in a Bolt the trend lines are very useful!
You know the distance to the next DCFC station. You know what your GOM currently shows. But your speed, elevation, the wind and temp can change during that leg and if you see your trend line way down by the min number and that is not good for getting to the DCFC station..
It's time to slow down a few mph and/or change the HVAC to use less power.
In 5 minutes or so you'll see the trend line moving back up toward the GOM number.

 

[SparkE]

In my 2015 Spark, it runs at whatever the last HVAC setting was during pre-conditioning. Fan speed, temp, etc. Others here have said that even with HVAC off, the inside is slightly warmed during pre-condition. (But was "auto" set???) YMMV.

 

[NORTON]

... Others here have said that even with HVAC off, the inside is slightly warmed during pre-condition. (But was "auto" set???) YMMV.

Easy enough to test!
Turn it all off on cold and dark winter night.
Precondition the next morning with the key fob.
Mine will also turn on the rear defrost if it's cold enough.

Good question: what if we RTFM?

 

[SparkE]

Good question: what if we RTFM?

The manual is remarkably crappy on providing much detail about it. I stopped reading after the FOURTH virtually identical cut-N-paste text about "remote start" of the vehicle strewn thoughout the manual. (I have the PDF file, and can search for text in the manual.)

trying this and that is a much better option in this case, IMO.

 

[Porsche]

I also find that with remote start, the cabin will pre-heat even if the HVAC is off. For me, existing fan settings are ignored, and I get more than adequate heating. If I'm not mistaken, during remote start all of the climate control settings are ignored, except for temperature so it knows whether to pre-heat or pre-cool. If it's not toasty warm, maybe you had the temperature set too low. I've also noted that when I turn off the pre-conditioning, the HVAC stays on, so I have to turn it off. Hmm, then again, that might be because my wife left it on during the last trip. Not sure if I have "auto" selected or not. I suppose for now, I'm also guilty of not RTFM, but I must say, even with checking the manual in the past, it does seem like I'm occasionally wrestling with the HVAC to get it to do what I want.