Preconditioning Vs. Climate on: Whats the difference?

[merc65fd]

I understand the purpose and benefits of preconditioning; warming the car, better range, faster charging..... What I would like like a little deeper dive on is this.

There are many ways to precondition the car. Scheduled departure, Navigation, turning climate on. Tesla states to turn the climate on to Precondition. Tesla Also says to turn on navigation so it will precondition before super charging which it does and says its doing so on the screen prior to the super charger arrival. So whats the difference between turning on climate preconditioning and the preconditioning that happens prior to supercharging in navigation? I mean climate is already on when you've been driving most likely. So if turning on climate is how you precondition at home, I don't understand whats happening with the preconditioning when it starts from navigation? Anyone have real facts on what the difference is, whats actually happening in the car? Also, if its 80 degrees out and it preconditions in Nav, is it making the battery even warmer?

 

[ucmndd]

Preconditioning by using climate control or scheduled departure = make the cabin a comfortable temperature. Additionally, if it's really cold, heat the battery for optimal efficiency/regeneration.

Preconditioning by using navigation to a supercharger = heat the battery, if necessary, for fastest charging speeds.

 

[GtiMart]

And to add to the good explanation already given, to better understand the difference: some typical battery temperature targets from recent software versions...

The preconditioning that happens in general with climate control should only heat the battery to around 7C (44F), give or take a couple degrees. If it's already there, it won't do anything. That is warm enough to get most of the regen power.

Preconditioning en route to a supercharger targets something like 40C (104F) or maybe more.

 

[merc65fd]

Preconditioning by using climate control or scheduled departure = make the cabin a comfortable temperature. Additionally, if it's really cold, heat the battery for optimal efficiency/regeneration.

Preconditioning by using navigation to a supercharger = heat the battery, if necessary, for fastest charging speeds.

I kind of feel like Tesla should have different names for the different processes. Turning on climate should not be called preconditioning, if preconditioning the battery is something completely different

 

[merc65fd]

And to add to the good explanation already given, to better understand the difference: some typical battery temperature targets from recent software versions...

The preconditioning that happens in general with climate control should only heat the battery to around 7C (44F), give or take a couple degrees. If it's already there, it won't do anything. That is warm enough to get most of the regen power.

Preconditioning en route to a supercharger targets something like 40C (104F) or maybe more.

Not to be redundant, but I really think Tesla should not call turning on climate Preconditioning. Doing so implies if you are leaving your house in the winter to supercharge you can simply turn your climate on 45 minutes before you leave your house. It also implies if it’s 80 degrees outside you don’t need to navigate to a supercharger because climate is on or at a comfortable temperature already

 

[GtiMart]

Ah well, I'm just the messenger Everything will work either way though, it's just a matter of how fast charging will be.

 

[jcanoe]

Preconditioning prior to Supercharging only happens when you enter the Supercharger location as the destination in the Tesla Navigation system.

Preconditioning for Supercharging will warm the battery pack to ~115F/46C. This is the optimal temperature for the most efficient, fastest Supercharger charging session. Depending on the outside temperature, when starting to drive preconditioning for Supercharging may initiate when you are a long distance, more than 30 minutes away from the Supercharger location.

This is much warmer than the battery warming that takes place while preconditioning or while charging using a Level 1 or Level 2 charging station.

 

[avs007]

The preconditioning that happens in general with climate control should only heat the battery to around 7C (44F), give or take a couple degrees. If it's already there, it won't do anything. That is warm enough to get most of the regen power.

I don't think that's right... I live on a hill, and even if it's 50 degrees outside (I have a fully finished garage, so on these same mornings, the car reports 52-55 degrees), I get next to zero regen going down our hill, unless I turned the climate on at least 30-45 minutes prior to leaving.

 

[GtiMart]

Those things can change with software updates. Last time I checked was last winter, I'll keep an eye when things get cooler in december. Last year conditioning would stop at 5C and battery would continue to creep up after that with residual heat. I would get a max of 50kW of regen, out of a total 85kW in normal conditions. Yes, if I went down a hill at that moment, max regen would reduce as it was getting used. That might be what you experience, you get some regen and it goes away because you use too much. At the bottom of the hill I tested, once I accelerated the max regen value would go back up. This adjustment of the max regen doesn't happen when everything is warm and toasty, or maybe it tolerates more at least.

 

[avs007]

Those things can change with software updates. Last time I checked was last winter, I'll keep an eye when things get cooler in december. Last year conditioning would stop at 5C and battery would continue to creep up after that with residual heat. I would get a max of 50kW of regen, out of a total 85kW in normal conditions. Yes, if I went down a hill at that moment, max regen would reduce as it was getting used. That might be what you experience, you get some regen and it goes away because you use too much. At the bottom of the hill I tested, once I accelerated the max regen value would go back up. This adjustment of the max regen doesn't happen when everything is warm and toasty, or maybe it tolerates more at least.

I guess that sounds about right... If I don't set climate ahead of time when it's 50 degrees, I get some regen at the top of the hill, but I have to stand on the brakes for the stop sign midway down the hill, and again at the signal at the bottom... But when I set the climate ahead of time, I can use regen all the way down the hill.

 

[DerbyCityY]

I have no first hand knowledge, so I may be wrong but I haven't seen it mentioned that if SOC is under 20% it will not precondition. This would be seen as a problem when trying to make it to the Super Charger.

 

[avs007]

I have no first hand knowledge, so I may be wrong but I haven't seen it mentioned that if SOC is under 20% it will not precondition. This would be seen as a problem when trying to make it to the Super Charger.

I'm pretty sure it will precondition as long as you arrive with 10% or higher. I arrived with 16% and remember it saying it was preconditioning. Likewise I also arrived with 6% and it didn't IIRC.

 

[GtiMart]

En route to the supercharger, the car will precondition even with low SOC. I've arrived at 4% once and, if memory serves me right, the car was preconditioning while I was driving there. I remember slowing down a bit to make sure I'd make it. I cannot tell if the car reduced its energy expense or if it went all-in but I arrived with a warm battery.

 

[merc65fd]

I have heard many times recently from Tesla that to be the most efficient don't accelerate quickly (obviously) or decelerate quickly. I dont understand the decelerate part of the advice. I always feel like decelerating quickly uses the most regen and would be a good thing. Any insight?

 

[GtiMart]

Regen is not 100% efficient, it's like 70-80%, in that ballpark. I guess that higher regen means higher kW of energy, and thus higher losses due to heat everywhere among that path. Similar to higher acceleration resulting in higher losses in heat.

 

[merc65fd]

Regen is not 100% efficient, it's like 70-80%, in that ballpark. I guess that higher regen means higher kW of energy, and thus higher losses due to heat everywhere among that path. Similar to higher acceleration resulting in higher losses in heat.

So if you are approaching a stop sign, it's better to stop gradually as apposed to waiting until the last second and stopping quickly, using regenerative braking in both instances?

 

[jcanoe]

For the comfort of your passengers slow and easy does it best. If driving by, for yourself whether maximizing regenerative braking or slowly lifting your foot from the accelerator won't change your overall efficiency much; not enough to be noticed.

Hypermilers have perfected the technique of pulsing power to the wheels and gliding (coasting). This hypermiling technique is not compatible with safe vehicle operation on public roads shared with other vehicles.

Any time you are engaging regenerative braking there are conversion losses as mechanical energy is converted into electrical energy and then stored in the battery. Coasting to a stop light or traffic signal requires extra distance. Coasting skips all of the conversion steps so it can be more efficient that regenerative braking. Friction braking is the least efficient method of slowing the vehicle as the mechanical energy is converted into heat and not recovered.

 

[merc65fd]

For the comfort of your passengers slow and easy does it best. If driving by, for yourself whether maximizing regenerative braking or slowly lifting your foot from the accelerator won't change your overall efficiency much; not enough to be noticed.

Hypermilers have perfected the technique of pulsing power to the wheels and gliding (coasting). This hypermiling technique is not compatible with safe vehicle operation on public roads shared with other vehicles.

Any time you are engaging regenerative braking there are conversion losses as mechanical energy is converted into electrical energy and then stored in the battery. Coasting to a stop light or traffic signal requires extra distance. Coasting skips all of the conversion steps so it can be more efficient that regenerative braking. Friction braking is the least efficient method of slowing the vehicle as the mechanical energy is converted into heat and not recovered.

I was speaking theoretically, not counting comfort. Just trying to figure why they are saying don't stop quickly for best efficiency. I mean if you have to stop it seems the rate of decent is not a big factor and probably has no impact on your efficiency. Unless I'm missing something

 

[jcanoe]

I was speaking theoretically, not counting comfort. Just trying to figure why they are saying don't stop quickly for best efficiency. I mean if you have to stop it seems the rate of decent is not a big factor and probably has no impact on your efficiency. Unless I'm missing something

Using less regenerative braking is closer to coasting. Of course if you miscalculate or run out of room and have to engage the friction brakes any theoretical savings is lost.

 

[merc65fd]

Sorry for the rabbit hole. Last comment on regen braking. It occurs to me that Tesla could be saying don't accelerate and decelerate repeatedly and try to maintain a slower speed where repeated quick deceleration is not needed.