Pre condition for small SC charging

[PagodaY]

I regularly make a 270 mile road trip (one way). While my (MY 2020) range tells me I can make this trip without stopping, I stop about 1/2 way through the trip to "top off" the battery just for piece of mind. I usually add about 10% and the charge takes less time than it takes me to discharge my liquid storage.

My car goes into Pre-Conditioning mode at some point before the SC stop to enable "fast charging". My question is - is it worth the extra kw to do this pre-conditioning while driving, if I'm not really interested in "fast charging" at the SC? Are there other benefits to doing the pre-conditioning?

 

[theothertom]

It's my understanding that waste heat from the motor(s) is used for preconditioning. I've read that a warm battery is a happy battery, so maybe there are other benefits to pre-conditioning.

 

[Big Earl]

It's my understanding that waste heat from the motor(s) is used for preconditioning. I've read that a warm battery is a happy battery, so maybe there are other benefits to pre-conditioning.

Not exactly "waste heat." It goes into a mode that consumes an extra 7 kW on dual motor cars (I've heard that heat pump cars might use up to 11 kW in some conditions, but I can't confirm). If you're just going for a quick +10% stop, I wouldn't bother preconditioning. A typical preconditioning session consumes 2 - 5 kWh depending on temperature. The car will enable battery heating when you plug in, but if you're only there for five minutes, it won't amount to much energy being wasted.

 

[theothertom]

It goes into a mode that consumes an extra 7 kW on dual motor cars

Good to know, thanks. I guess that means I shouldn't pre-condition if I'm running low on range.

 

[Big Earl]

Good to know, thanks. I guess that means I shouldn't pre-condition if I'm running low on range.

I think it's smart enough to not precondition if it thinks you aren't going to make it.

 

[theothertom]

I think it's smart enough to not precondition if it thinks you aren't going to make it.

Thanks

 

[ATPMSD]

If you set the SC as the destination the car is going to pre-condition, otherwise it will not. It is the pre-conditioning that allows you to stop in “less time than it takes me to discharge my liquid storage.“ Try it both ways and decide.

 

[PagodaY]

Based on everyone's response I gather there is no down side to cancelling the pre-condition in my specific situation. Good to know.

On my past few trips, I've cancelled the pre-conditioning when it appears in the NAV display on the way to the SC and I still have a completed charge when I arrive back at the car, so the charging is not slowing me down appreciably.

I always check the initial rate of charge before leaving the vehicle and it is usually under 100kw/h (SCV3). I can't tell what the charge rate was when the battery completed charging. My SOC before charging is about 42% and I charge to 53%.

As an aside, boy I wish the car's screen would have the ability to dial in a specific charge level, not try by fiddling with the triangle beneath the battery display. I have to resort to the app, which seems silly.

 

[Big Earl]

As an aside, boy I wish the car's screen would have the ability to dial in a specific charge level, not try by fiddling with the triangle beneath the battery display. I have to resort to the app, which seems silly.

You don't have to fiddle with the little triangle. You can touch or drag anywhere within the battery on that screen.

 

[PagodaY]

Yeah I know that, but both methods are so "hit and miss" when trying to set the charge level to anything other than the stops at 10s and 5s.

Is this a big deal? No. Just a slightly annoying quirk that could be so easily fixed via software. Maybe they'll get around to this once they've solved all the other issues that are ahead on the list.

 

[GtiMart]

For information, clicking on the "preconditioning" message in the navigation makes the message disappear but preconditioning doesn't stop. I looked at ScanMyTesla a few weeks ago on a trip and I could still see both of my motors expending energy to heat the battery.

 

[PagodaY]

Wow, that's not good news about pre-conditioning not stopping.
I don't want to cast aspersions, but can anyone confirm GtiMart's observations?

 

[Big Earl]

Wow, that's not good news about pre-conditioning not stopping.
I don't want to cast aspersions, but can anyone confirm GtiMart's observations?

@GtiMart is correct. Tapping the pre-conditioning message just makes the message go away; it does not stop pre-conditioning. To avoid preconditioning, you have to navigate to some location other than the Supercharger.

 

[PagodaY]

So, this week, when I'm doing this trip, I'll navigate to the Stewart's instead of the supercharger at that location. I'll keep track of what happens.

Thanks for everyone's input!

 

[Big Earl]

The car will probably scold you with a message that says Next Time--Navigate to Supercharger, battery will precondition for faster charging.

 

[PagodaY]

Just what I need, another scolding from my car! If it knew what I was buying at the Stewarts, it would probably scold me for that too! Wait... it probably DOES know what I'm buying. The internal camera analyses what I'm consuming and sends that info on to the mother ship to determine how much mass it needs to protect with airbags, etc. As long as that info is not shared with my wife, I'm good.

 

[Regaj]

The ideal charging temperature - for battery health - is ~20C/68F). Pre-conditioning, when your pack is at or above that temperature is good for the user experience (faster DC charging), but actually not so good for your battery. Electrons excite more readily when the environment is heated - which is why pre-conditioning accelerates your pack's absorption of the DC charge. But heat is also probably the greatest enemy of your pack's long-term health.

Charging during cold temps stresses the battery, too. Pre-conditioning under 20C/68F would be a benefit to battery health.

I love Tesla. But their pre-conditioning regimen is all about making their business work better, not your battery.