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Did you know the 3 heats the battery (actively) constantly while DC charging at any speed or temp?

FalconFour

Supporting Member
Mar 25, 2016
140
237
San Jose, CA
I cold soaked her last night, unplugged. Plugged her in this morning and this is what is being reported by Statsapp.
View attachment 486052
eventually it should ramp the charge rate
We're specifically talking about DC charging here. It's well known and expected that it'll warm up a cold battery. It's not so well established that it'll bake a warm battery, though, as we're discovering.
 

derotam

Member
Oct 31, 2018
825
700
Oak Hill, VA
I have never seen specific battery heating while charging at the same rate, even down to 30F... And I am watching the OBDII data.

Allow me to walk back my comment as I am known to be wrong on occasion. I did not have OBDII data until recently so I don't have data for cold temps yet. I did just see heating with a pack temp of 7C and the heating stayed on for a bit, but I need to get more data before trying to determine how the system fully behaves.
 

diamond.g

Active Member
Nov 5, 2015
2,421
1,361
Moyock, NC
We're specifically talking about DC charging here. It's well known and expected that it'll warm up a cold battery. It's not so well established that it'll bake a warm battery, though, as we're discovering.
That is fair. My scan tool is too cumbersome to gather that kind of data. Will have to rely on others with scan my tesla.
 

camalaio

Active Member
May 28, 2019
1,483
2,093
Vernon, BC, Canada
This is obviously not true. The battery is heated to prevent health impacts, so that the charge rate can be increased.

You could put in 250kW to a model 3 battery at any time but it would be ruined, and even more so when it's cold.

Re-contextualise what I said though. The heating isn't necessary because it's already allowed to charge fast enough without additional heating. It of course won't let you "put in 250kW" at any time for various reasons, but specifically in regards to temperature it's already limiting you from doing so if it would be detrimental. Right?

If I actually was able to get a faster charging rate with a hotter pack, sure, I might appreciate the intentional heating if speed of charging is my goal.

Just found this thread and noticed weird heating behavior yesterday too. Was charging up to 80% and the car kept heating the battery (generating heat with stator and i saw increasing stator and battery inlet temps) ALL THE WAY to 80%, even when the car "knew" it would be finished charging in a few minutes.

Now you might say "well it needed to be warm for the charginging" but that's actually not true. Scan My Tesla shows the max allowable charge rate for any given moment (based on temps and SoC) and i could see that the battery was able to charge at a much higher rate than i was getting (was paired with another car) so clearly at the kW rate i was using, i didn't need the batteries quite as hot as Tesla wanted.

I have no concern about wasting energy, but i then drove around for the next 20-30 minutes with my pack temp around 110F which seems a bit high. Also for track days this means that you really want to finish supercharging and start track mode ASAP to get that pack temp down before hitting the track.

Also - be nice to each other lol

Though I've been very vocal about not liking their current heating scheme (mostly in regards to slower charge speeds), this might be a more defensible case. It might be readying itself for when you become the only vehicle on that Supercharger pair so that it can accept more power, which I think is a noble if unrealistic pursuit depending on the situation.

However, I'm skeptical that helps much since above 70% you're starting to get very limited in charge rate (less than 70kW if I recall correctly) and like you said, it's showing you can theoretically take more power.

I found that funny, there is never "too fast" if you're on a long trip and wanna get going...

Like another pointed out (thanks @FalconFour), you missed the very important following three words: "for that case". Where that case was grabbing dinner.

Even on a long trip I find myself in this situation especially around dinner time. A longer break is sometimes appreciated, certainly longer than a Supercharger would give considering I need to park, walk somewhere, and eventually walk back before charging is done. We can hardly grab a nearby coffee at some Superchargers and make it back in time because the walking alone takes time. This is especially useful if you want to get more charge at the top end where charging is slower.

However if there are no services and I'm truly just stopping to charge (rare, honestly) then yes, charge me up as fast as possible!


So this is AC charging and outside of most of the point of this thread, but I find it hard to believe it ramped up significantly within just 10 minutes? Implying it heated the pack in less than 10 minutes? That said I'm sure the target temp for AC charging is much different and there could even be other factors to what the Stats app was displaying.
 
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diamond.g

Active Member
Nov 5, 2015
2,421
1,361
Moyock, NC
Re-contextualise what I said though. The heating isn't necessary because it's already allowed to charge fast enough without additional heating. It of course won't let you "put in 250kW" at any time for various reasons, but specifically in regards to temperature it's already limiting you from doing so if it would be detrimental. Right?

If I actually was able to get a faster charging rate with a hotter pack, sure, I might appreciate the intentional heating if speed of charging is my goal.



Though I've been very vocal about not liking their current heating scheme (mostly in regards to slower charge speeds), this might be a more defensible case. It might be readying itself for when you become the only vehicle on that Supercharger pair so that it can accept more power, which I think is a noble if unrealistic pursuit depending on the situation.

However, I'm skeptical that helps much since above 70% you're starting to get very limited in charge rate (less than 70kW if I recall correctly) and like you said, it's showing you can theoretically take more power.



Like another pointed out (thanks @FalconFour), you missed the very important following three words: "for that case". Where that case was grabbing dinner.

Even on a long trip I find myself in this situation especially around dinner time. A longer break is sometimes appreciated, certainly longer than a Supercharger would give considering I need to park, walk somewhere, and eventually walk back before charging is done. We can hardly grab a nearby coffee at some Superchargers and make it back in time because the walking alone takes time. This is especially useful if you want to get more charge at the top end where charging is slower.

However if there are no services and I'm truly just stopping to charge (rare, honestly) then yes, charge me up as fast as possible!



So this is AC charging and outside of most of the point of this thread, but I find it hard to believe it ramped up significantly within just 10 minutes? Implying it heated the pack in less than 10 minutes? That said I'm sure the target temp for AC charging is much different and there could even be other factors to what the Stats app was displaying.
Yeah not sure what possessed me to post AC charging stuff. IIRC Stats isn’t inferring any charging data, it is coming from the API.

Does the S/X exhibit the same battery heating behavior?
 

SouthSeas

Member
Nov 26, 2019
201
48
Pennsylvania
This is obviously not true. The battery is heated to prevent health impacts, so that the charge rate can be increased.

You could put in 250kW to a model 3 battery at any time but it would be ruined, and even more so when it's cold.

You seem to be arguing with yourself. The purpose is to charge faster. Of course it will be done in a way to not damage the battery. That's a given. But the purpose remains to charge the battery faster. The BMS won't let you charge fast enough to damage the battery, so no point in even talking about that.
 
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