Premature 'preconditioning battery for fast supercharging...?'

[rincewind]

Here's my recent experience. I had a road trip of 130 miles, so I programmed the Nav to stop at a Supercharger as a first stop. I had a 105 mile journey to the SC, which took nearly two hours. The battery preconditioning started the moment I began the journey, then stopped a few minutes later, proceeding to start and stop 3 more times before the final start as I got to within about 15 miles of the SC.

That cannot be correct surely?

 

[GtiMart]

Yes, I believe it is now the new way. It is heating the battery all along but it just needs to spend energy to generate heat a few minutes at a time, a few times. The message only appears when energy is being spent.
Motors heat up and then the glycol circulates transferring that heat into the pack. The car keeps the motors just a few degrees C higher than the current pack temp.
Prior, the conditioning would start later, motors would heat up way higher, and the glycol would probably enter the pack hotter. More stressful overall for many components, probably not a better result as the heat transfer is limited by physics

 

[BigNick]

It preconditions longer so that the batteries warm completely to the center of the cells. Starting and stopping allows the battery pack to come up to temperature gradually and evenly. This results in better charging performance and likely better battery longevity.

Think of the preconditioning a pack full of thick cold-soaked 4680s will take being more than double the diameter of the 2170s and triple the 18650s.

 

[rrolsbe]

Earl good point! It looks like the 4680 cells might be cooled/heated via a heat transfer plate located at one end of the batteries which would appear to be much less surface area than the current method.

 

[rrolsbe]

Yes, I believe it is now the new way. It is heating the battery all along but it just needs to spend energy to generate heat a few minutes at a time, a few times. The message only appears when energy is being spent.
Motors heat up and then the glycol circulates transferring that heat into the pack. The car keeps the motors just a few degrees C higher than the current pack temp.
Prior, the conditioning would start later, motors would heat up way higher, and the glycol would probably enter the pack hotter. More stressful overall for many components, probably not a better result as the heat transfer is limited by physics

Your comments make a lot of sense but I can't help thinking this change in heating strategy has something to do with newer cars with heat pumps (ie. they can scavenge heat from the traction battery)?

 

[GtiMart]

That is a good comment. It's possible that heatpump cars behave a bit differently, the heatpump can probably also provide heat to warm the battery... You would have to listen to some of the youtube videos that explain the octovalve system. I have a non-heatpump 2020 model.

 

[Nabush]

Hello, is there a study showing how much more energy usage this preconditioning for supercharging uses ? My wh/mile suck on mine but this message stays on all the time on big trip so wonsering if it impacts efficiency....

 

[Nabush]

Hello, is there a study showing how much more energy usage this preconditioning for supercharging uses ? My wh/mile suck on mine but this message stays on all the time on big trip so wonsering if it impacts efficiency....

Could not find how to edit my post... But yea on my last trips from Boise to Portland (28-38F) the battery preconditioning message stayed on between all supercharging stops. At the same time battery usage has been a lot worse than whar the planner (or ABRP) estimated. Like 9% more battery usage than initially planned. Firsr lef was showing 50% battery usage, used 58%. There was wind though. But this preconditioning has to be using more energy also. Wondering how much...

 

[Big Earl]

The effects of preconditioning can be seen in the trip planner. The dip at the 80 mile mark in this screen shot is where pre conditioning started. My efficiency started out batter than typical, but ended up dipping down to a little worse than typical by the end of the trip.

How much energy is required to heat the battery depends on how cold the pack is and what the exterior temperature is during the trip. Very cold weather will require more energy than mild weather. A larger pack will require more energy than a smaller pack.

 

[brkaus]

I noticed this on a recent trip. The precondition dialog popped up on and off for about 50 minutes.

I liked the results.

 

[Nabush]

View attachment 744593

The effects of preconditioning can be seen in the trip planner. The dip at the 80 mile mark in this screen shot is where pre conditioning started. My efficiency started out batter than typical, but ended up dipping down to a little worse than typical by the end of the trip.

How much energy is required to heat the battery depends on how cold the pack is and what the exterior temperature is during the trip. Very cold weather will require more energy than mild weather. A larger pack will require more energy than a smaller pack.

On my last trip, the battery preconditioning has been on all the time between superchargers... Where I drove, I had to supercharge every 100miles or so...
I got caught in a snow storm, there was so much wind that the car was doing 410wh/miles (plus elevation changes). Between Boise-Portland or Boise-Kennewick/tri cities my 2021 LR has less range than an SR+. I don't even know how an SR+ could do the trip by bad weather....55% of battery was barely doing 105-110 miles...

 

[Big Earl]

On my last trip, the battery preconditioning has been on all the time between superchargers... Where I drove, I had to supercharge every 100miles or so...
I got caught in a snow storm, there was so much wind that the car was doing 410wh/miles (plus elevation changes). Between Boise-Portland or Boise-Kennewick/tri cities my 2021 LR has less range than an SR+. I don't even know how an SR+ could do the trip by bad weather....55% of battery was barely doing 105-110 miles...

Yep. Snow and wind can be rough on range. Imagine how much time it would take if it didn’t heat the battery and your max charge rate was <50 kW.

 

[holmgang]

This morning my car left a 20C climate controlled garage with 95% battery. Ambient outside temp is 5C.

Navigation distance was 2.5hrs to the next Supercharger. Preconditioning was on the entire leg.

Next charging stop was 1.5hrs away. Preconditioning was on that entire segment too.

 

[GtiMart]

@holmgang, do you have a single motor or two? Single motors can almost never generate waste heat because they're almost always driving the car forward.

 

[holmgang]

@holmgang, do you have a single motor or two? Single motors can almost never generate waste heat because they're almost always driving the car forward.

2x980s

 

[holmgang]

The charging destination was to the v3 250kw chargers. Maybe needs extra warming for that power

 

[rrolsbe]

The charging destination was to the v3 250kw chargers. Maybe needs extra warming for that power

I believe the algorithm only

The charging destination was to the v3 250kw chargers. Maybe needs extra warming for that power

I believe the battery heating algorithm only takes into account that it is DC charging. Even if it is a 72KW urban charger makes no difference. I was sitting in a traffic jam in LA last Monday with an estimated arrival time to an Urban charger 90 minutes later when SMT showed battery temp of 127F and stator temp of 145F. When I set the navigation destination to a business across the street from that Urban charger, the stator temp started dropping. When I got within a mile of the charger, I switched the navigation back to the charger, charged at max of 72KW just fine.

 

[ranss12]

Look at the picture attached. 57F outside temperature, 100% battery charge, traveling from Manchester, CT to Rochester, NY. Supercharger preconditioning came on immediately even though my next charging station was more than 220 miles away. My lifetime Model Y Whr/mile is 237 over 12,000 miles, but on this leg of the trip it was over 500 Wh/m and I was never going to make it to the scheduled Supercharger. This was on the 2nd day of my Model Y ownership as I was driving it back from the Mt. Kisco delivery point. I am not a new Tesla driver - I traded in a Model 3 with 52,000 miles for this Model Y. I think there is a problem with their preconditioning.

algorithm.
Since then I have learned to turn off preconditioning and this has rarely (if ever) caused a reduction in Supercharging rate.