Does Preconditioning Really Matter?

[Kitten]

• The preconditioning of the battery will only be effective while it's plugged in. The system will look at the current temperature and then determine how much in advance it has to start to precondition the battery. The cabin is the last to precondition.
• Setting a departure time when it's NOT plugged will act like a remote start and just concentrate on the cabin.
• You only really need to precondition when you need max range, or extremely cold temps, and it should be plugged in anyway.

Makes sense. Thanks.

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[SpaceEVDriver]

@TonyaE, you asked a question in another thread and I wanted to point you to this conversation about preconditioning.

 

[TonyaE]

@TonyaE, you asked a question in another thread and I wanted to point you to this conversation about preconditioning.

Thank you. I’ve looked but don’t think my question was really answered.

 

[SpaceEVDriver]

I need help with understanding the preconditioning (set departure time) vs remote start. I plan to charge from 9pm-6am. I leave at different times everyday for work. Would I set departure time for 6am? I may not leave until 10:30 am. Do remote start 15 minutes before I leave or will it stay preconditioned from 6am departure schedule?

I also leave at variable times. If I need the battery to be nicely preconditioned but not necessarily at 100%, I set a reminder in my phone for about 60-30 minutes before departure and then tell the car to charge to 100%. It won't reach that charge, but that's okay, I'm really trying to get the battery warmed up. Then 10 minutes before I leave, I start the car (keeping it on the "charge to 100%" setting).

If I need it to be at full charge, I usually just tell it to charge to 100% the night before. This doesn't necessarily precondition the battery if the charge ends at 06:00 and I leave at 09:00, but it's usually been okay. I still start the car 10-20 minutes before leaving.

There's nothing that flexible in the FordPass app, unfortunately.

 

[TonyaE]

You guys bare with me. This will be my first EV. I asked this in another thread and was kindly ignored One nice person suggested this thread.
I will charge from 9pm-6am nightly (off peak). Should I set departure time for 6am so the car will be preconditioned? I may not leave home until until 9am or 10:30am. The start of my workday varies daily. Should I also remote start the car before I leave? It gets pretty hot where I am.

 

[TonyaE]

I also leave at variable times. If I need the battery to be nicely preconditioned but not necessarily at 100%, I set a reminder in my phone for about 60-30 minutes before departure and then tell the car to charge to 100%. It won't reach that charge, but that's okay, I'm really trying to get the battery warmed up. Then 10 minutes before I leave, I start the car (keeping it on the "charge to 100%" setting).

I also leave at variable times. If I need the battery to be nicely preconditioned but not necessarily at 100%, I set a reminder in my phone for about 60-30 minutes before departure and then tell the car to charge to 100%. It won't reach that charge, but that's okay, I'm really trying to get the battery warmed up. Then 10 minutes before I leave, I start the car (keeping it on the "charge to 100%" setting).

If I need it to be at full charge, I usually just tell it to charge to 100% the night before. This doesn't necessarily precondition the battery if the charge ends at 06:00 and I leave at 09:00, but it's usually been okay. I still start the car 10-20 minutes before leaving.

There's nothing that flexible in the FordPass app, unfortunately.

If I need it to be at full charge, I usually just tell it to charge to 100% the night before. This doesn't necessarily precondition the battery if the charge ends at 06:00 and I leave at 09:00, but it's usually been okay. I still start the car 10-20 minutes before leaving.

There's nothing that flexible in the FordPass app, unfortunately.

So you don’t set a standard departure time. You precondition based on when you think you are leaving? Am I getting that right? If you set car to charge to 90% nightly until 6am let’s say. So if you plan to leave about 0930, you hit charge to 100% at 0800?

 

[ctenidae]

It's not just the batteries that get preconditioned. It warms/cools your cabin too, using line power rather than battery power. That way you only need to maintain temp, not achieve it. It takes a lot to warm up a well cold soaked car interior.

 

[SpaceEVDriver]

So you don’t set a standard departure time. You precondition based on when you think you are leaving? Am I getting that right? If you set car to charge to 90% nightly until 6am let’s say. So if you plan to leave about 0930, you hit charge to 100% at 0800?

Basically, yes.

My partner has times set for when she goes to the gym. Those are regular, early mornings. She tells the car to be ready by 05:30 MWF.

We keep it charged up to 85% or 90% all nights.

If know I'm going somewhere at 09:00, I'll tell the car to start charging at 08:00.

 

[TonyaE]

Basically, yes.

My partner has times set for when she goes to the gym. Those are regular, early mornings. She tells the car to be ready by 05:30 MWF.

We keep it charged up to 85% or 90% all nights.

If know I'm going somewhere at 09:00, I'll tell the car to start charging at 08:00.

That makes sense. Thanks

 

[SpaceEVDriver]

That makes sense. Thanks

But if you want the cabin to be warm (or cool), you'll also have to tell it to Start 10 or 20 minutes before you leave.

All of this is best done while plugged into your L2 charging station so you're drawing grid power, not HVB power.

 

[ckt]

Very interested to know how much more range one would get if preconditioning is used to do a highway trip from 100% SOC down to 5% SOC? Thoughts? Can one expect greater than 5% increase in range assuming exterior temp is 32F (at all times) and car was preconditioned outside?

 

[SpaceEVDriver]

Very interested to know how much more range one would get if preconditioning is used to do a highway trip from 100% SOC down to 5% SOC? Thoughts? Can one expect greater than 5% increase in range assuming exterior temp is 32F (at all times) and car was preconditioned outside?

I haven't done the experiments, but obviously one such experiment was done by the OP, but for a much shorter range. There are several other similar experiments discussed in the forum.

There are a couple of things that will impact the answer to your question.

• Theoretically, you could gain up to about 30% increase in battery capacity if you precondition, depending on the temperatures. This isn't an increase in efficiency, but it is an increase in range. Someone else gave the pretty good analogy of a gallon jug of water left outside as a way of thinking about your battery capacity. If it's cold enough, some ice will form in the jug and you won't be able to pour the entire gallon of water out of the jug. This is a decent analogy to how batteries work in the cold. You can't get the full 91 kWh from it if it's too cold. Preconditioning "melts" that "ice" and allows you access to more of the battery.
• How much of your drive to the highway is stop-and-go? Starting at 100% SOC impacts the battery's ability to accept regenerative power from braking, so you'll lose a bit of efficiency if you start at 100% compared with if you start at, say 90% or 95%. But only if you have to drive a "lot" in stop-and-go before you get to the freeway. I haven't tested if you lose enough efficiency to warrant starting at a lower SOC (i.e., if you start at 95%, can you gain at least 5% range via regen?).
• How hard do you accelerate? If you accelerate too hard, you lose battery capacity. The only (poor) analogy I can come up with is to think about a rubber tube with a hole in it. If you put more pressure on that tube trying to push more fluid through it, the hole will expand and more fluid will escape through the hole. If you push just the right amount through, you lose very little (or none). This is nonlinear. The faster you discharge the battery, the less capacity you have. With hard accelerations, you're losing both efficiency and capacity.
• Preconditioning also warms up the interior. How much you use the HVAC will determine how much this impacts your efficiency. If you use grid power to warm up your car, you aren't using battery capacity which can be used to move your vehicle. You do still use energy, but you get longer range.
• I'm sure I'm missing some others. It's early for me and I just finished my coffee.

A lot of people mix up efficiency and battery capacity, which is fine. There isn't always a clean line between the two. If you precondition you can go farther, partly because you have higher battery capacity and partly because you have a right-temperature cabin, lending you more power for moving. If you charge to 100% before stop-and-go, you might be able to go farther, but you won't have the same efficiency because regen won't be as active.

This seems all very technical and complex. But really, just set a departure time or set a reminder in your phone to charge to a higher % SOC and start the car before you leave if it's not something that happens regularly.

Back when I was a kid, we had to pre-condition our ICE vehicles. We'd put a big bucket of fireplace coals under the engine and cover the engine with a heavy wool blanket. Then when we started it up, we would leave it running for 10-30 minutes to warm up the cabin and the engine and transmission (if it was an AT). Honestly, the EV preconditioning is a lot more forgiving and a heck of a lot easier.

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