Preconditioning Improves Range up to 20% [Ford Brochure]

[RickMachE]

So with the new update, how does one precondition? Asking for a friend

Setting a departure time, plugged in, is still the only way.

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[RickMachE]

Non-scientific:

Vehicle charges to 90%, warm battery due to charging. Has 90% SOC at end. 82kWh.

Battery cools. Still 90%, but now 73kWh.

Battery warms on its on due to temperature going up. Ends up back at 82kWh, and stays at 90%.

You drive, and it stays at 90% for a while, because it warms more than when it was charged, and gains 1kWh.

 

[RickMachE]

True, but only to the ambient temperature at the time you were driving. If the wind chill caused by driving feels like ‐20F on a 5F degree day and you stick your hand out the window, both your hand and you car will chill to 5F, only faster than if you sat in your parked car under the same conditions, doing the same thing (don't try this at home ?). While wind chill speeds heat loss, it does not decrease ambient temperature. It will not chill to -20 F under either condition.

Perhaps you realize this, but many others do not. I had a guy tell me on a sub-freezing, windy Minnesota day, not to park my car facing the wind because "It'll freeze your block to 40 below!" When I didn't move my car, he said "You'll be sorry!"

I wasn't sorry.

Physics.

However, that blasting wind, while not having a wind chill effect, will cool the engine block faster.

True story - living in Erie, PA. Parked at Cleveland Airport, went skiing for a week. Came home, bitterly cold. Car would not start, battery fine. Engine block was simply too cold. Got rental car and hotel. Next morning pushed it into the sunlight, with hood open, and connected rental car's battery. A few hours later, it started. There was maybe 2 inches of snow. In Erie, more than 4 feet.

 

[ArthurDOB]

However, that blasting wind, while not having a wind chill effect, will cool the engine block faster.

True story - living in Erie, PA. Parked at Cleveland Airport, went skiing for a week. Came home, bitterly cold. Car would not start, battery fine. Engine block was simply too cold. Got rental car and hotel. Next morning pushed it into the sunlight, with hood open, and connected rental car's battery. A few hours later, it started. There was maybe 2 inches of snow. In Erie, more than 4 feet.

Yes, I did say that it would happen faster.

 

[superdave80]

At 8% I don't see much benefit to spend the money preconditioning unless you need absolutely all of your range in a trip.

But you will have to then use power to warm/cool your cabin from your battery, so you are still spending money on electricity.

 

[astronut325]

Question: Should we be setting multiple departure times during cold nights to keep the battery in an ideal temperature? Or just the morning commute departure? Trying to ensure battery life stays long, not necessarily concerned with range/performance.

 

[SpaceEVDriver]

Question: Should we be setting multiple departure times during cold nights to keep the battery in an ideal temperature? Or just the morning commute departure? Trying to ensure battery life stays long, not necessarily concerned with range/performance.

I live in a colder-but-not-COLD area (lowest temperatures get to about -15 F, but that's once or twice during the worst part of winter). The Mustang lives outside. We just leave the vehicle plugged in overnight. We do not set multiple departure times. The car will maintain its battery temperature above harmfully low temperatures. It won't keep it up at the ideal temperature, but it's good enough.

 

[AKgrampy]

But you will have to then use power to warm/cool your cabin from your battery, so you are still spending money on electricity.

Not advising one way or another but you can pre-heat cabin without preconditioning batteries. No extra range but not as much electricity used as in preconditioning.

 

[Mach-Lee]

Question: Should we be setting multiple departure times during cold nights to keep the battery in an ideal temperature? Or just the morning commute departure? Trying to ensure battery life stays long, not necessarily concerned with range/performance.

No, just leave it plugged into an active Level 2 EVSE at night and set one morning departure time.

Staying plugged into Level 2 will ensure the battery stays above freezing. Level 1 will not keep up in cold climates and only heats after charging is complete (charges a freezing battery). It may take an additional 2 hours after charging is complete to heat the battery on Level 1. If L1 charging does not complete, then the battery stays cold.

If you park in freezing temperatures, you really need a Level 2.

Extreme cold will not damage the battery as long as it’s not being used or charged. The battery must be warmed up before those should occur.

 

[SpaceEVDriver]

Your example is perfect for my present conundrum! First the simple part: heat up battery and the SOC drops as a warmer battery can hold more electrons and therefore more kWh. Now here is the rub and it is really obvious in your case - you can’t increase the electrons in the battery without shoving more in. In your case you are draining the battery at 6 kW for the time period so how can your battery charge increase? It should have decreased.

Another good but opposite example is I would drive 10 miles in the winter, start with SOC of 90 and end with 93. That was due to battery cooling down and computation of SOC. Back to garage later car would warm up and the SOC would change but there is no way the kW could increase unless I charged the battery.

Or maybe I have to do a bit more research on batteries!

Nope.
Batteries are not volumetric containers.
They're chemical potential energy devices. When a battery warms up, the rate of chemical reactions increases. The internal chemistry increasing in activity means the battery increases its state of charge (adds electrons). Even when it uses its own energy to warm itself up!

A well-designed battery can do that, anyway. A poorly-designed battery could go too far and create a run-away reaction that causes it to burn up.

Oh, and this is really going to bake your noodle.

The slower you discharge (for reasonable discharge rates), the more you can pull from the battery. These batteries generally have a rated capacity based on a 1C or close to 1C discharge rate. That is, for a battery with rating of 100 kWh of capacity, a discharge rate of 1C means it takes one hour to fully discharge (a discharge rate of 100 kW) and you'll get 100 kWh of usable energy from the battery.

But if you take, say three hours to discharge that battery (33 kW), you might get something like 120 kWh of usable energy from the same battery.

And if you discharge the battery at a faster rate, say 200 kW rate, you might only get 80 kWh of usable energy from the battery.

The main reason we see longer range at lower speeds is aerodynamic drag. But another factor is that if the discharge rate is low enough, you can get more energy out of the battery than the 1C rated capacity suggests.

I don't have the charts in front of me, so these are made-up numbers.

 

[AKgrampy]

Oh, and this is really going to bake your noodle.

The slower you discharge (for reasonable discharge rates), the more you can pull from the battery. These batteries generally have a rated capacity based on a 1C or close to 1C discharge rate. That is, for a battery with rating of 100 kWh of capacity, a discharge rate of 1C means it takes one hour to fully discharge (a discharge rate of 100 kW) and you'll get 100 kWh of usable energy from the battery.

But if you take, say three hours to discharge that battery (33 kW), you might get something like 120 kWh of usable energy from the same battery.

And if you discharge the battery at a faster rate, say 200 kW rate, you might only get 80 kWh of usable energy from the battery.

The main reason we see longer range at lower speeds is aerodynamic drag. But another factor is that if the discharge rate is low enough, you can get more energy out of the battery than the 1C rated capacity suggests.

I don't have the charts in front of me, so these are made-up numbers.

I have to study this a bit more but something does not seem quite right. I understand there are many actions and parameters involved; however, if you store say 50kW of energy in the battery I just can’t see how it is possible to pull out more than 50kW. As a matter of fact you should pull out less as there should be losses involved. The more I think about it the more I am sure there is more to this. If you are correct then you have solved the worlds energy problem. We will charge a battery to 100 kW then slowly discharge and pull out 200 kW while charging two batteries to 100 kW each. Repeat and we will have 400 kW. That is not possible!

 

[SpaceEVDriver]

I have to study this a bit more but something does not seem quite right. I understand there are many actions and parameters involved; however, if you store say 50kW of energy in the battery I just can’t see how it is possible to pull out more than 50kW. As a matter of fact you should pull out less as there should be losses involved. The more I think about it the more I am sure there is more to this. If you are correct then you have solved the worlds energy problem. We will charge a battery to 100 kW then slowly discharge and pull out 200 kW while charging two batteries to 100 kW each. Repeat and we will have 400 kW. That is not possible!

No.

The battery manufacturers need to provide a capacity rating based on some discharge rate and the standard is 1C.

The capacity rating given is based on a particular extraction rate, which creates a specific internal resistance. If the extraction rate is higher, the internal resistance increases and the amount of useful energy that can be extracted is lowered. If the extraction rate is lower, the internal resistance is lower and more useful energy can be extracted. But, the lower the rate of energy extraction, the higher the ratio of resistance to usable energy, so at some point of slow extraction, it's just not worth it.

There's obviously a maximum amount of energy that can be extracted because there's a specific amount of chemistry that can happen.

 

[dbsb3233]

But you will have to then use power to warm/cool your cabin from your battery, so you are still spending money on electricity.

And that's surely where a lot of the "range" savings are coming from: initial cabin preheating off the plug instead the battery.

I find a lot of this inapplicable. Range typically only matters on road trips. And we're usually only plugged in overnight for the first leg of the day (and not even that at many hotels). Still useful a few times per year, but not much more than that unless one has really long daily commutes.

 

[Woeo]

I definitely get better efficiency after preconditioning because the car doesn’t have to waste battery energy to heat the battery to a decent range. Unfortunately preconditioning was pretty expensive, at least $20/month so I stopped doing it every day. It’s a trade off of battery cycles vs electricity cost.

The efficiency calculation reported by the preconditioned car after a drive does not include the energy pulled from the wall to heat the battery.

 

[Sam2084]

The efficiency calculation reported by the preconditioned car after a drive does not include the energy pulled from the wall to heat the battery.

Exactly. If I don’t precondition, the energy needed to heat the pack comes from the battery, killing my efficiency.

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