Potential Preheat Discovery: Depends on Regen

[camalaio]

Hey folks,

As I've commented elsewhere, our LR AWD definitely preheats the battery pack sometimes now along with preheating the cabin. However, it doesn't always do this. It even does it when not plugged in, so I wasn't clear on when it would decide to do it.

I've recently noticed a correlation with the regen setting though. I toggle it a lot based on driving conditions. When set to Low, I don't think it has preheated the battery. When set to Standard, it does seem to preheat.

This may be a fluke, but could also make sense. With Low regen, you would benefit far less from the battery being warmed.

Thoughts? Anyone else observe this?

 

[640k]

this seems largely anecdotal to me. what reasoning are you basing this off of? the availability of regen? the wh/mi? something else?

 

[SD_Engnr]

Hey folks,

As I've commented elsewhere, our LR AWD definitely preheats the battery pack sometimes now along with preheating the cabin. However, it doesn't always do this. It even does it when not plugged in, so I wasn't clear on when it would decide to do it.

I've recently noticed a correlation with the regen setting though. I toggle it a lot based on driving conditions. When set to Low, I don't think it has preheated the battery. When set to Standard, it does seem to preheat.

This may be a fluke, but could also make sense. With Low regen, you would benefit far less from the battery being warmed.

Thoughts? Anyone else observe this?

How do you know that the battery is being preheated? What's your source/validation?

 

[ZOMGVTEK]

This is roughly my assumption as well. It appears to be less aggressive about the preheating depending on SOC. I didn't attempt to change the regen setting to see if that has an impact, but it is quite plausible. In my experience it appears to stop preheating the pack when it hits the temp that shows roughly 3 regen dots. So this means as SOC drops, the preheat temp drops as well. This makes sense, so its quite plausible I think. At high SOC it takes forever for it to stop preheating, and as SOC drops its clearly much faster.

@SD_Engnr -The dual motor car makes a fairly noticeable high freqency noise from the front drive unit, along with a fair bit of pump noise when its preheating the battery. It's quite noticeable.

 

[camalaio]

this seems largely anecdotal to me. what reasoning are you basing this off of? the availability of regen? the wh/mi? something else?

How do you know that the battery is being preheated? What's your source/validation?

@ZOMGVTEK pointed it out as well, but the battery preheat seems fairly noticeable for multiple reasons. One is that the sounds made are fairly unique (similar/same to those heard while Level 3 charging, which will actively heat the pack a lot). And yes, definitely via amount of available regen. When it's -20°C outside and about 0°C in the garage, I know not to expect much regen. And left outside in those temps, I definitely expect almost no regen at all.

I agree the low vs. standard settings are largely anecdotal, thus the question at the bottom of my original post. While the preheat behaviour seems to have come in a recent-ish update, it's fairly clear that it is indeed actively heating the battery sometimes when preheating the cabin.

 

[rrolsbe]

If the HVAC is set to the new CAMP mode, my testing shows no traction battery heating only cabin heating. I can hear the rear motor when the traction battery is being heated; likewise, I used the Scan My Tesla setup to verify the stator was not being sent any current.

 

[ZOMGVTEK]

If the HVAC is set to the new CAMP mode, my testing shows no traction battery heating only cabin heating. I can hear the rear motor when the traction battery is being heated; likewise, I used the Scan My Tesla setup to verify the stator was not being sent any current.

That would make sense, since it does heat the battery when the climate keep is on, at least after you exit the car.

 

[GtiMart]

I have scanmytesla and I'm set on low regen. I can tell you that under 3 degrees C there is no regen, the maxregen value is at 0. The battery gets heated when I heat the cabin so I don't think it's a function or the regen mode. I've been at 80% charge and at 40% charge and it made no difference either. The battery needs to be a few degrees above 0c, maybe 6-7, before I get a good 30kw regen maximum. I've seen a value for "target batt active heat" in scanmytesla and it's currently at 10C. I believe it will preheat anytime the battery is under that.

 

[ZOMGVTEK]

I have scanmytesla and I'm set on low regen. I can tell you that under 3 degrees C there is no regen, the maxregen value is at 0. The battery gets heated when I heat the cabin so I don't think it's a function or the regen mode. I've been at 80% charge and at 40% charge and it made no difference either. The battery needs to be a few degrees above 0c, maybe 6-7, before I get a good 30kw regen maximum. I've seen a value for "target batt active heat" in scanmytesla and it's currently at 10C. I believe it will preheat anytime the battery is under that.

It preheats most anytime the battery is a bit chilly, but I think the question is where does it stop?

 

[GtiMart]

Ah...based on the target I see I would think it'll stop at 10C but I have not verified it. My car often sleeps in a heated garage and I don't preheat long enough at work to observe that it's done at a certain temp. I'll try to remember and check that.