Battery Preconditioning: Some measured data.

[Gullwingdmc]

You should check out @Mach-Lee's tests too.

https://www.macheforum.com/site/thr...ting-taking-requests.24393/page-7#post-570808

@Mach-Lee is the best!

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[Mach-Lee]

And here's the full plot of the HVB temperature. It's clear that the car started warming the battery right at that ~30 km (18 mile) range (just before 14:07). I started charging at about 14:39. So either the battery cooled off from the target temperature or the car overshot the target temperature.

Ah, battery went from 12ºC to 26ºC (∆T = +14ºC) during the en-route precondition. So this seems designed around you preconditioning on L2 before you leave so the battery starts at 12ºC or so. If you do not precondition before your trip, the first DCFC will still be slow because the battery will not be warmed up enough (unless you were just driving downhill). I was wondering why it was only 30 km, the engineers must have designed the feature with the assumption the pack would start in the 12-15ºC range after a departure time precondition.

In your case the pack was warmed up quite a bit from extensive regen before your charging stop. For most others driving on flat land, the battery will probably only be in the 5ºC range in cold temps.

In summary, I want to make an important point: L2 departure time preconditioning + en-route preconditioning must be used TOGETHER to achieve desired results.

 

[SpaceEVDriver]

Ah, battery went from 12ºC to 26ºC during the en-route precondition. So this seems designed around you preconditioning on L2 before you leave so the battery starts at 12ºC or so. If you do not precondition before your trip, the first DCFC will still be slow because the battery will not be warmed up enough (unless you were just driving downhill). I was wondering why it was only 30 km, the engineers must designed the feature with the assumption the pack would start in the 12-15ºC range after a departure time precondition.

In your case the pack was warmed up quite a bit from extensive regen before your charging stop. For most others driving on flat land, the battery will probably only be in the 5ºC range in cold temps.

In summary, I want to make an important point: departure time preconditioning + en-route preconditioning must be used TOGETHER to achieve desired results.

Yeah, this trip had a lot more regen than we usually experience on our longer trips.

I really need to get my L2 charger re-installed (we moved and took the charger with us, but I haven't had time to install it yet).

 

[Murse-In-Airy]

I may have a chance to collect more data next week. I’m going to have to find which car my OBD reader is in and get more familiar with car scanner. But there is a good chance I’ll be doing a long drive in 10° F weather.

 

[Ride_the_lightning]

Ah, battery went from 12ºC to 26ºC (∆T = +14ºC) during the en-route precondition. So this seems designed around you preconditioning on L2 before you leave so the battery starts at 12ºC or so. If you do not precondition before your trip, the first DCFC will still be slow because the battery will not be warmed up enough (unless you were just driving downhill). I was wondering why it was only 30 km, the engineers must have designed the feature with the assumption the pack would start in the 12-15ºC range after a departure time precondition.

In your case the pack was warmed up quite a bit from extensive regen before your charging stop. For most others driving on flat land, the battery will probably only be in the 5ºC range in cold temps.

In summary, I want to make an important point: L2 departure time preconditioning + en-route preconditioning must be used TOGETHER to achieve desired results.

There is no way your pack stays warm after driving 300 miles, even if you L2 precondition. I’ve plotted that data on my own, and the pack starts to cool off significantly within 30 minutes of leaving my house. After an 80% drop in capacity on a long trip the battery would be very cold again (except for any effects of regen).

 

[the golden eel]

Then I began to wonder if we could use that same capability to cause the car to do a better job of conditioning (warming) the battery before going on a long trip or before going on a trip when it's cold. I think we can, and I think it does a bit better job than setting a Departure Time.

Can you expand on what you are thinking here?

Thanks for the thread and sharing all your info.

 

[SpaceEVDriver]

Can you expand on what you are thinking here?

Thanks for the thread and sharing all your info.

In the general EV universe, one of the concerns for range, charge speed, and long-term battery life is its operating temperature.

I'm not all that concerned about long-term battery life on the Mustang. There are so many ways Ford was excessively conservative that I'm confident I'll have more than 90% health after 200,000 miles. (I don't take the car to the track and rarely hit its maximum acceleration.)

I do like to arrive at my destination with all the kWh I can have. A secondary concern to me is speed of charging. To maximize battery capacity and efficiency, and to improve charge speed without reducing battery health, operating temperature should be kept at ideal temperature for its use case at any given moment. That is, when charging the battery should be at one temperature. When driving at highway speeds, it should be at a different temperature. Etc.

Ford did not provide a perfect vehicle. One way that less-than-perfect nature shows is that the battery isn't at an ideal temperature for cold-weather driving in the first 30-60 minutes even after setting the Mustang to be prepared with a departure time.

There is also no one-button way to tell the Mustang to precondition the battery for driving whenever you like. I do know that the car tries its darndest to set its battery temperature to the ideal if you let it know you're going to be at a DCFC at least 18 miles from the charger.

A work-around for cold-weather driving might be to tell the car you're going to a nearby DCFC (within 18 miles) before you start driving. There are several more parameters to test with this (one example: does it work better at low SOC? I did all my testing at high SOC). I also don't have my Level 2 charger installed and the car may not be pulling enough juice to do its best on my Level 1 charger.

If that doesn't explain clearly, let me know. I tend to get bogged down in minutiae when I'm geeking out.

 

[the golden eel]

Thanks for the detailed reply. Yes, I understand what you are saying.

My ears perked up when you said this... "Then I began to wonder if we could use that same capability to cause the car to do a better job of conditioning (warming) the battery before going on a long trip or before going on a trip when it's cold. I think we can, and I think it does a bit better job than setting a Departure Time."

I was wondering if you meant there was a way to trick the car into doing a battery pre-condition while it is not plugged in. Like remote start, enter a DCFC location - but then don't drive anywhere, just let the battery warm itself.

I have not used the Ford navigation myself, I always use android auto. Just thinking out loud.

 

[Murse-In-Airy]

Thanks for the detailed reply. Yes, I understand what you are saying.

My ears perked up when you said this... "Then I began to wonder if we could use that same capability to cause the car to do a better job of conditioning (warming) the battery before going on a long trip or before going on a trip when it's cold. I think we can, and I think it does a bit better job than setting a Departure Time."

I was wondering if you meant there was a way to trick the car into doing a battery pre-condition while it is not plugged in. Like remote start, enter a DCFC location - but then don't drive anywhere, just let the battery warm itself.

I have not used the Ford navigation myself, I always use android auto. Just thinking out loud.

In theory this will work. Turn car on and set a waypoint in Ford Nav to a DCFC station less than 30km from your current location. However, without being plugged in you’ll simply be using battery power to warm the battery. Depending on how cold the battery is, you’ll most likely lose more range by warming the battery, than you would gain by having a warm battery.

 

[Logal727]

Is there any preconditioning that is done for when pack heat is too high? Like in warmer climates? Is this a thing on any other vehicles?

 

[the golden eel]

In theory this will work. Turn car on and set a waypoint in Ford Nav to a DCFC station less than 30km from your current location. However, without being plugged in you’ll simply be using battery power to warm the battery. Depending on how cold the battery is, you’ll most likely lose more range by warming the battery, than you would gain by having a warm battery.

Oh I agree completely. I wasn't asking for range so much as battery health. @Mach-Lee mentions that dumping all the energy from regen braking into a cold battery is bad for it - and I know that my friend's tesla does not use near as much regen braking when his battery is cold.

So I was just thinking out loud about how to warm the battery after sitting all day at work with no access to a charger. Especially on days like today when it's below zero (Fahrenheit) outside.

 

[AZBill]

30 km is 18.641 miles, so yeah 18-19 mi range approximately, just wanted to verify it's 30 km. My view is that isn't long enough to get the battery up to a desirable temp of 70ºF or higher for full speed DCFC right off the bat. Your data shows it still had to heat the battery for a while after plugging in.

GM is using a 30 minute rule to start the pre-conditioning, rather than miles from the charger. That logic makes more sense.

 

[ckt]

Has anyone been able to find out at what SoC % will battery nav preconditioning won't work at? Assuming 100% wouldn't work. I.e. battery nav precondition while 100% SoC in Garage plugged in level 2.

 

[AZBill]

Is there any preconditioning that is done for when pack heat is too high? Like in warmer climates? Is this a thing on any other vehicles?

The pack cooling is always running when the battery gets warm, too much heat is not good for the battery whether it is charging or discharging.

 

[SpaceEVDriver]

Has anyone been able to find out at what SoC % will battery nav preconditioning won't work at? Assuming 100% wouldn't work. I.e. battery nav precondition while 100% SoC in Garage plugged in level 2.

This is a good question. I'll be running an ~1200 mile trip in the near future and will gather data, but I'm not going to lay out specific testing just to test this (it's a work trip). I'll report back with the data I do gather, though.

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