Used 6% to pre-condition

[Dannyk123]

Set my car to pre-condition this morning (Model 3 LFP) and it used 6% battery.

I wonder what the actual benefit of doing this is? I only drive a small distance in the morning - it usually uses 1-2% for the journey. Should i bother pre-conditioning as it uses so much battery to do so.

It was cold.

 

[Dannyk123]

\Sorry i found all the answers i needed on another thread but can't seem to delete this.

short version - its not worth pre-conditioning for short journeys

 

[Dannyk123]

Pre-conditioning for short trips

Happy new owner of LR M3. Looking for ideas about setting a schedule to pre-condition for short trips, we work from home and often only use the car once a day for 5-10 miles, different times of day. Apart from the somewhat inconvenience of setting a schedule and then remembering to cancel it...

teslamotorsclub.com

 

[toolman335]

It is amazing how much energy people will use to get their battery up to temperature just to drive a few miles. They'll still stand by the process too and just claim it uses power from the house. Well....that's power lol

 

[Regaj]

If one's concern is only how many kWh's are consumed, then heating the cabin is certainly an option that can be thrown to the curb.

But it's a more complicated story than that. Lithium plating is arguably the worst phenomenon that faces EV drivers. And Lithium plating accelerates significantly at higher C-rates and at lower temperatures.

That's why Tesla's BMS limits regen when the pack is very cold. Unfortunately, what Tesla cannot do is prevent the car from being driven when the pack is very cold - they'd sell no cars if they did. So what they do is externally heat the pack via waste heat from the stators, getting the pack out of that danger zone where lithium plating occurs as quickly as possible.

But if you just get into your cold Tesla with its cold pack and simply drive away, you are subjecting your pack to some amount of risk.

In the OP's example, consuming 6% (it was actually probably somewhat less than that, but that's a different thing) to adequately heat the pack, even for a very short journey, is a trade I'd make every single time.

 

[Dannyk123]

If one's concern is only how many kWh's are consumed, then heating the cabin is certainly an option that can be thrown to the curb.

But it's a more complicated story than that. Lithium plating is arguably the worst phenomenon that faces EV drivers. And Lithium plating accelerates significantly at higher C-rates and at lower temperatures.

That's why Tesla's BMS limits regen when the pack is very cold. Unfortunately, what Tesla cannot do is prevent the car from being driven when the pack is very cold - they'd sell no cars if they did. So what they do is externally heat the pack via waste heat from the stators, getting the pack out of that danger zone where lithium plating occurs as quickly as possible.

But if you just get into your cold Tesla with its cold pack and simply drive away, you are subjecting your pack to some amount of risk.

In the OP's example, consuming 6% (it was actually probably somewhat less than that, but that's a different thing) to adequately heat the pack, even for a very short journey, is a trade I'd make every single time.

Thanks for your feedback, very interesting topic.
In reality, for me, it doesn't matter if the energy consumption is high as it is mostly paid for by work.
But also, the degradation of the battery is not a major concern as it's a lease car on a 4 year term.
In my opinion Tesla should offer more guidance on this, maybe they don't quite know the impact of treating the battery badly in cold climates, we may see more information as time passes.
The 6% loss from early hours to pre-conditioned state was noticeable, usually I can expect 1 % loss overnight but this % was on top of that.

 

[toolman335]

If one's concern is only how many kWh's are consumed, then heating the cabin is certainly an option that can be thrown to the curb.

But it's a more complicated story than that. Lithium plating is arguably the worst phenomenon that faces EV drivers. And Lithium plating accelerates significantly at higher C-rates and at lower temperatures.

That's why Tesla's BMS limits regen when the pack is very cold. Unfortunately, what Tesla cannot do is prevent the car from being driven when the pack is very cold - they'd sell no cars if they did. So what they do is externally heat the pack via waste heat from the stators, getting the pack out of that danger zone where lithium plating occurs as quickly as possible.

But if you just get into your cold Tesla with its cold pack and simply drive away, you are subjecting your pack to some amount of risk.

In the OP's example, consuming 6% (it was actually probably somewhat less than that, but that's a different thing) to adequately heat the pack, even for a very short journey, is a trade I'd make every single time.

What is the "some amount of risk?"
How do you define that and what do you predict will happen?

 

[ucmndd]

In the OP's example, consuming 6% (it was actually probably somewhat less than that, but that's a different thing) to adequately heat the pack, even for a very short journey, is a trade I'd make every single time.

Are you saying you think such a fantastic waste of energy is warranted, or isn’t?

 

[ucmndd]

short version - its not worth pre-conditioning for short journeys

It’s basically never the right thing to do from an energy perspective. Frankly any other perceived benefits are dubious at best.

 

[Regaj]

What is the "some amount of risk?"
How do you define that and what do you predict will happen?

"Risk" depends upon how hard you accelerate, how fast you drive, at what pack temp, and for how long before the pack is warmed.

What will happen to someone who drives a lot with a cold pack? They'll see more rapid deterioration of their pack than they would otherwise.

Whether that's important or not is up to every individual to decide. I'm just pointing out that there is a sound, rational reason why Tesla "pre-conditions" the way they do.

 

[KenC]

Interesting topic, lithium plating. I remember reading about it several years ago, when there was that technical thread. Cathode cracking at high SOCs was the primary issue that caught my eye, but the secondary issue was lithium plating.

At the time, I don't recall the temperature issue related to lithium plating, I just remember that the downside is potentially slower acceleration and slower charging rates in the future as plating increases.

Anecdotally, I've only occasionally pre-conditioned, as I usually forget by the time I have to leave. On the plus side, it's natural to drive a little more slowly when it's cold out. Your tires are cold so a bit out of round, etc. The tendency is also to accelerate more slowly as the road surface may be a little more slippery as well.

Essentially, there's been so little conversation on lithium plating, that I didn't realize there was anything constructive to do!

 

[jjrandorin]

Interesting topic, lithium plating. I remember reading about it several years ago, when there was that technical thread. Cathode cracking at high SOCs was the primary issue that caught my eye, but the secondary issue was lithium plating.

At the time, I don't recall the temperature issue related to lithium plating, I just remember that the downside is potentially slower acceleration and slower charging rates in the future as plating increases.

Anecdotally, I've only occasionally pre-conditioned, as I usually forget by the time I have to leave. On the plus side, it's natural to drive a little more slowly when it's cold out. Your tires are cold so a bit out of round, etc. The tendency is also to accelerate more slowly as the road surface may be a little more slippery as well.

Essentially, there's been so little conversation on lithium plating, that I didn't realize there was anything constructive to do!

Well, whatever you are doing with your car is "the right thing" based on the degradation charts you have posted for your car. At this point, if you told me you spun around 3 times and tapped your leg twice with your left hand before you got in the car every day, and that helped your degradation, I would at least consider it

 

[Rocky_H]

But if you just get into your cold Tesla with its cold pack and simply drive away, you are subjecting your pack to some amount of risk.

Well, no. If full regen were always available all the time, regardless of what temperature the battery pack is, then what you're saying would be true. But...

That's why Tesla's BMS limits regen when the pack is very cold.

Exactly. This is WHY regen is so limited or nonexistent when the battery is cold. They have set it to accommodate how much charging power is allowed per the temperature of the cells, and it keeps charging power very restricted to avoid that so that it doesn't cause this lithium plating damage.

 

[ucmndd]

"Risk" depends upon how hard you accelerate, how fast you drive, at what pack temp, and for how long before the pack is warmed.

IMO there is no risk that warrants using 4x the energy necessary to complete a trip. The risks you’ve offered up in defense of such a practice are extremely speculative.

 

[toolman335]

"Risk" depends upon how hard you accelerate, how fast you drive, at what pack temp, and for how long before the pack is warmed.

What will happen to someone who drives a lot with a cold pack? They'll see more rapid deterioration of their pack than they would otherwise.

Whether that's important or not is up to every individual to decide. I'm just pointing out that there is a sound, rational reason why Tesla "pre-conditions" the way they do.

No, this is why the car limits its "performance" when the battery is still cold. If we could full throttle with full regen in cold temps with a cold battery? Ok man, then I'd believe we're harming the battery.
Meanwhile there's enough fear mongering going around to convince people that we need to use 4x the normal amount of power to warm the car up for short drives.

 

[804son]

I use preconditioning to warm the cabin and provide better regenerative braking. All else is pure speculation. If the value of driving experience (warm cabin/better regeneritive braking) is not worth the cost of energy to do so. Then I get that, It's a personal choice.
That is all there is to the decision of preconditioning or not.
I have seen no proof that preconditioning or not, does any harm either way to the battery.

 

[yesimon]

Lithium plating specifically happens near and below freezing temperatures. A 50F=10C "it's cold" day poses no risk of lithium plating so there's no justification whatsoever of preconditioning "to protect the battery".

At freezing temps, your power will be limited both acceleration *and* regen. This helps mitigate most of the risk of lithium plating. Once current reaches ~1C the risk increases greatly, which is why max regen and supercharging are the two most noticeable uses impacted. Discharging/accelerating at 1C is uncommon unless you have a lead foot so it's less noticeable to most people.