[KevinW]

I leave my car outside (carport) during the winter, and wondering if it is a "best practice" to have the vehicle plugged into my Level 2 charger. My preference, lacking guidance, is to only plug in when I need to charge from ~20% to ~80%, as opposed to every time I park the car in my carport.

Taken from a different website:

"

1. Minimize exposure to low temperatures—Here again, the danger is mostly parking unplugged in extreme low temperatures. If you can plug in, the battery's thermal management system can keep the battery comfy. Some EVs automatically run the thermal management system even unplugged, until capacity drops to 15 percent, after which things get ugly.

"

Thanks in advance

 

[Rousie13]

If you can easily plug your car in every night, then I recommend doing it. You can control charge rates/percentages, so it will stop charging when you want it to. When I schedule departures/etc in my model 3, it will pull power from the EVSE so your battery is at your set percentage when you’re ready to leave. Also when the car is plugged in and I open the door to cause the heat/ac to kick on, you can see the car pulling current from the EVSE.

 

[fiehlsport]

Not sure on this. I don't know how the ID.4 manages battery temps when plugged in, if at all.

Tesla pulses the stators in each motor to warm up the battery when you do remote climate. VW does not. Does anyone know how the ID.4 heats the battery? Resistance heater elements within the battery, or in the coolant loop?

 

[SunWizard]

Does anyone know how the ID.4 heats the battery?

Its now been confirmed by VW in the NHTSA docs that the ID.4:
< 46°F: heating battery by the Z132 Heating Element (PTC) in the coolant loop
95°F (in vehicle operation): cooling by the heat exchanger for heat condenser (AC)
86°F (during charging): cooling by the heat exchanger for heat condenser (AC)
At a temperature of 59°F (15°C) or higher the thermostat opens, allowing battery coolant to flow to the radiator (passive cooling).
No need for any pre-conditioning for charging unless its <46F then it will always be heating, but only while charging or driving.

 

[surprising]

As @SunWizard points out, it appears no active battery management if not plugged or in operation. I can confirm during crazy heat wave (110+) we got in the pacific nw this summer that I never heard the fans turn on while it sat in my driveway unplugged.

I only plug in to charge at EA stations every few days. I wonder if I am doing damage by not having it plugged in when not in use..

 

[VW TECHNICIAN]

Not sure on this. I don't know how the ID.4 manages battery temps when plugged in, if at all.

Tesla pulses the stators in each motor to warm up the battery when you do remote climate. VW does not. Does anyone know how the ID.4 heats the battery? Resistance heater elements within the battery, or in the coolant loop?

It has coolant heater dedicated for battery heating.

 

[VW TECHNICIAN]

As @SunWizard points out, it appears no active battery management if not plugged or in operation. I can confirm during crazy heat wave (110+) we got in the pacific nw this summer that I never heard the fans turn on while it sat in my driveway unplugged.

I only plug in to charge at EA stations every few days. I wonder if I am doing damage by not having it plugged in when not in use..

It has passive and active cooling or heating when necessary...difference is that when plugged to L1 or L2 it will keep temperature with different calibration temperature threshold vs unplugged.
Cold has very little effect on battery life. ..and there are algorithms that will lower max discharge when started cold until onboard coolant heater brings the battery to sweet spot.
Battery BMS continuously adjust max charge or discharge depending on various sensors information....
Active battery management is always watching...plugged.... not plugged.

 

[SunWizard]

The question I still have is whether the battery heater will be active as needed (<46F) when left plugged in, but not charging. If it does not, that would be mean charging as late as possible before driving would be the best strategy to keep battery >46F. So that the car battery doesn't get consumed to provide that initial battery warming at startup.

Edit: and the opposite would be true for cooling when really hot, which some of you southerners might already be able to answer whether the AC condensor fan comes on and off when plugged in but not actively charging.

 

[VW TECHNICIAN]

The question I still have is whether the battery heater will be active as needed (<46F) when left plugged in, but not charging. If it does not, that would be mean charging as late as possible before driving would be the best strategy to keep battery >46F.

Yes ...when plugged it will draw power from L2 and if not enough power it will use battery and continue to charge when battery management has heated battery...
When unplugged it will have different calibration and algorithms that will keep battery warm with battery pack minimum impact on SOC .
Algorithms when not plugged will prefer lower temperature and wait for owner to start driving what is more efficient than keeping battery unnecessary at the sweet spot. Also electronics loop will be used for less use of onboard coolant heater to heat battery from electronics waisted heat ( radiator will be completely bypassed).
Take better look at the battery management diagram.

 

[VW TECHNICIAN]

There is two mixing valves one is thermostat operation and another is thermostat and solenoid dual purpose operation mode.

 

[Otto]

The question I still have is whether the battery heater will be active as needed (<46F) when left plugged in, but not charging. If it does not, that would be mean charging as late as possible before driving would be the best strategy to keep battery >46F. So that the car battery doesn't get consumed to provide that initial battery warming at startup.

Edit: and the opposite would be true for cooling when really hot, which some of you southerners might already be able to answer whether the AC condensor fan comes on and off when plugged in but not actively charging.

I assume that if my level 2 EVSE that I currently use to schedule charging is not in the charging time period but still plugged in means that the car can't pull any current even for conditioning the battery? (if that is a thing that is done)

 

[d287]

I assume that if my level 2 EVSE that I currently use to schedule charing is turned not in the charging time period but still plugged in means that the car can't pull any current even for conditioning the battery? (if that is a thing that is done)

That sounds likely… when it is off it should be just as if the car is unplugged

 

[Nai3t]

I assume that if my level 2 EVSE that I currently use to schedule charing is turned not in the charging time period but still plugged in means that the car can't pull any current even for conditioning the battery? (if that is a thing that is done)

That's correct. There is no provision in the J1772 protocol to allow negotiated or cooperative charging. The EVSE can only communicate "X amps are available" to the car, and the car's charger has no way to request power from the EVSE.

But timed charging ought to be working early next year, so just get through this cold winter and all will be sun and flowers. :/

 

[Don]

Personally, I wouldn't be worried about it at 46F. If temps were forecasted to go below freezing, I think I would plug it in, although the only real danger with lithiums in cold weather is to make sure you're NOT charging them when the actual battery temp is below freezing

There are many EV's (and I own a couple of them) which have no battery thermal management system at all and they are sold in places like Canada and Norway and extreme cold hasn't been seen to be a problem with them for the past 10 years. Still, with a new $40K car, if I had an available plug and it was forecasted to get really cold, my car would be plugged in . . . . but mine are kept in garages so even when it's 20 degrees outside, they're relatively safe - But, if it ever gets THAT cold here, it will be plugged in regardless, just in case

Don

 

[Otto]

That's correct. There is no provision in the J1772 protocol to allow negotiated or cooperative charging. The EVSE can only communicate "X amps are available" to the car, and the car's charger has no way to request power from the EVSE.

But timed charging ought to be working early next year, so just get through this cold winter and all will be sun and flowers. :/

That is a shame. Thinking about it if I were design something today I think I would allow the car to call for “accessory” power outside of proper charging if it is plugged in and not providing power. The EVSE could then decide if it should supply the power and how much.

I’m sure there are reasons why this isn’t the case but seems like it could be beneficial.

 

[Joe_U698745]

Has anyone found info in the Users Manual about keeping the car plugged into the EVSE for battery management purposes. I've looked in various places in the manual and have found zero information.

I've had 2 Chevy Volts previous to the ID.4 and GM did go out of there way to mention the importance of keeping the EVSE plugged into the car for battery heating in cold weather and battery cooling in warm.

It could be that the ID.4 battery is large enough that maybe it doesn't matter if the EVSE is plugged in or not.

 

[Nai3t]

I have a recollection from past posts that this system is being built out by VW and that whatever we have now is not in its final form. Maybe that's why we're lacking specific info?

Like your Volts, my i3s have had a lot of good manufacturer-provided info out there explaining the operational parameters of some of these systems. I'm thankful we have @VW TECHNICIAN on this site; he's provided valuable insight into our ID.4s I haven't seen elsewhere.

 

[edid4]

I have a WallBox Pulsar Plus EVSE and as long as it is plugged in and a charge session is scheduled CarNet can not initiate charging. If I remove the charge schedule from the WallBox then CarNet can initiate charging. I just tried this so I know it works.

So if I'm sitting in the house warm and cozy and the outside temp is going to take a dip below 46F I just remove the scheduled charge from the EVSE and the ID.4 should then be able to request power when needed. Is this correct?

 

[jgoodnough]

This seems like another application for an EVSE that allows for reduction of charging current. By slowing down the charge rate you could extend the charging time so the car would be finishing up it's overnight charge just before you want to leave in the AM. The side benefit is the car would remain "on-power" so it can continue warming the battery during the entire charge period. My Juicebox 40 allows the charging amps to be adjusted to a desired level. It also has a "minimum charge" setting but I've never been able to figure out what that does. Perhaps it provides a trickle-like charge that will keep the thermal management system operating?

 

[Nai3t]

...for an EVSE that allows for reduction of charging current. ... Perhaps it provides a trickle-like charge that will keep the thermal management system operating?

This might be getting into symmantics, so sorry if this is what you meant, but all EVSE's do allow reduction of current. The EVSE can advertise 60 amps and the car can pull as little or as much as it likes.

Your approach is ideal, but with the current state of our charging tech requires the car to make these calculations, since the EVSE can't see the battery's state of charge.

A car that's charging right before departure can have a battery pre-heated by latent heat of charging, and at other times, the rate can be kept to a minimum to go easy on the battery.

What better system to provide this functionality than the car's? As long as it has power available, it calls all the shots. If the EVSE was doing it, it would be blind to what's happening at the other end of the cord.