Battery preconditioning for CCS-1?

[Earl]

I don’t think Tesla puts that much thought into what owners experience when charging.

Remember that for about its first decade, and to some extent, still, Tesla's CTO was JB Straubel and he had a lot of control over all of the technology at Tesla. He was famous for driving an EV from LA to SF quite regularly and was very concerned about the charging experience since he suffered through it when it wasn't available.
There are rumors of him opening up breaker-boxes and willing facilities en-route and clamping jumper cables (that he carried with him) directly onto the 240v rails in order to charge at as high a current as possible.
He had resourcefully done it the hard way himself so he knew how important it was and ensured that his cars made it possible for his customers as easily as possible. Unfortunately, none of the engineers at the other auto and charging companies had such experience or wisdom.

 

[DonTom]

I don't think it's likely for Tesla to add a manual preconditioning control. If a CCS charging network ever gets it's act together and provides reliable sites, Tesla is more likely to add them the the nav planner and precondition automatically for them.

I almost never use the Tesla App, but I was just playing around with it and found this under "Schedule" :

"Precondition
Set climate and preheat battery"

Mine is set to "off" as default.

Anyway, can that be used to precondition the battery for a CCS charge on a cold day?

Or what am I really looking at there?

-Don- Reno, NV

 

[Supcom]

I almost never use the Tesla App, but I was just playing around with it and found this under "Schedule" :

"Precondition
Set climate and preheat battery"

Mine is set to "off" as default.

Anyway, can that be used to precondition the battery for a CCS charge on a cold day?

Or what am I really looking at there?

-Don- Reno, NV

No. Preconditioning with the app only warms the battery to an efficient operating temperature. It's something like 40 degF, or so, as I recall. Preconditioning for supercharging warms to around 125 degF.

I did a test yesterday driving from the Denison, TX supercharger to the Francis Energy DCFC in McAlester, OK. This site is far, far from any Tesla Supercharger, so it is not possible to just set the nav to a nearby SC site.

What I did was to set the nav to the Tulsa SC site, which routed me past the McAlester site. The downside is the car did not fully precondition, but did warm to about 109 degF. Presumably, the car gently warmed the battery using the waste heat the battery generates as the energy display showed no energy used for preconditioning. It was a warm day, so that should have helped.

When I got to McAlester, I got 122 kW peak with 48% battery. That's just a bit shy of what I would get with a properly preconditioned battery, but certainly acceptable.

 

[Rocky_H]

Anyway, can that be used to precondition the battery for a CCS charge on a cold day?

No, and specifically, it's because Tesla did something confusing by using the exact same word to refer to two totally different things.

That term preconditioning used in the cabin climate settings is prewarming the cabin, and it just barely warms the battery to above freezing as kind of a side effect.

When you are in drive gear and select a Supercharger in navigation, the use of the word preconditioning there is getting the battery really HOT, so it can take very high power charging. It's a much higher temperature target than the warming with cabin climate control.

 

[DonTom]

No, and specifically, it's because Tesla did something confusing by using the exact same word to refer to two totally different things.

That term preconditioning used in the cabin climate settings is prewarming the cabin, and it just barely warms the battery to above freezing as kind of a side effect.

When you are in drive gear and select a Supercharger in navigation, the use of the word preconditioning there is getting the battery really HOT, so it can take very high power charging. It's a much higher temperature target than the warming with cabin climate control.

How about when we do a 12 KW home charge when it is below freezing? Does the battery still need to warm up a little somehow even then? I think I heard that lith batteries will not accept a charge at freezing temps, so how is that then dealt with?

-Don- Reno, NV

 

[DonTom]

When you are in drive gear and select a Supercharger in navigation, the use of the word preconditioning there is getting the battery really HOT,

How many watts are needed to do such on a very cold day? And how long does it usually take?

-Don- Reno, NV

 

[Rocky_H]

How about when we do a 12 KW home charge when it is below freezing? Does the battery still need to warm up a little somehow even then? I think I heard that lith batteries will not accept a charge at freezing temps, so how is that then dealt with?

How many watts are needed to do such on a very cold day? And how long does it usually take?

These are both kind of related to the same answer. As to the first part, it's still built into the car's charging logic. If it is extremely cold and well below freezing, it turns on battery warming and will not do any charging at all until it gets warmed up some. And then it will start off with fairly slow charging and then continue to increase the charging power as temperatures continue to rise, because....

This gets to the answer to both questions:
There isn't exactly just one single all or nothing switch, where it's either no charging at all or blast the energy into it as fast as possible. There's this continually increasing curve I've seen graphs of. Picture amps on the Y axis and temperature on the X axis. There is this rising curve, where as the battery gets warmer and warmer, it can take a bit more power while still staying under this damaging threshold.

So it will warm up some to be able to take a 12kW power level, but that doesn't take all that much because 12kW on an 80kWh sized battery is very low charging power. But then to be able to pump 150 kW into that same sized battery? Well, that has to be much warmer.

 

[DonTom]

As to the first part, it's still built into the car's charging logic.

Then does the battery also warm up a little before a CCS charge starts on a Tesla? If not, what happens if a CCS charge is attempted when well below 32°F?

-Don- Reno, NV

 

[Supcom]

Then does the battery also warm up a little before a CCS charge starts on a Tesla? If not, what happens if a CCS charge is attempted when well below 32°F?

-Don- Reno, NV

If you show up to any DCFC without preconditioning, then the car will use some of the energy from the charger to heat the battery. During this time, the car will not charge as quickly as it would if you had preconditioned.

With ALL charging methods from L1 to L3, no charging will occur until the battery is heated up above freezing. The car will request enough power to heat the battery. If the battery is really cold, like -20F, it can take a long time before energy goes into the battery.

 

[DuncanM]

Then does the battery also warm up a little before a CCS charge starts on a Tesla? If not, what happens if a CCS charge is attempted when well below 32°F?

-Don- Reno, NV

The only way to warm the battery (other than an external add-on like the SEXY buttons) to a high temperature prior to CCS1 DCFCing is to spoof the car by navigating to a Telsa SC but arrive at a CCS1 DCFC instead. If you are near a CCS1 charging station, and the car is parked you can schedule a cabin and battery preheat (precondition), which will warm the battery up enough to accept regenning and slowish DCFCing (~30kw) depending on the temperature. However, when the car is connected to a DCFC the car will begin to heat the battery rapidly and the CCS1 charge rate will increase steadily over time. The car will not allow a higher rate of charge than the battery can safely accept.

 

[Rocky_H]

Then does the battery also warm up a little before a CCS charge starts on a Tesla? If not, what happens if a CCS charge is attempted when well below 32°F?

The car knows that temperature curve very well and won't let it harm itself. It's the same with a CCS as with a Supercharger. Several years ago someone from the San Francisco area came through Boise and visited with me and then went on to Twin Falls and stayed overnight at a hotel. They didn't know about this Winter stuff, and it got very cold, like single digits outside and got the car very chilled. They were expecting to just stop by the Supercharger, fill up and go in the morning. But when they plugged in, he said it spent about 30 minutes just using power from the station to run the battery heater before it ever even got warm enough to begin charging, and then started off with low power and gradually increased from there.

 

[DonTom]

On the contrary, Tesla has put much thought and billions of dollars into making your charging a very boring experience. Drive up, plug in, go pee.

I agree, but they made it a little too boring for many. There are many things I would rather do myself.

-Don- Reno, NV

 

[Earl]

There are many things I would rather do myself.

Yes, but are you sure that you (and the millions of others who would get access to doing things themself) actually know how to do things yourself with batteries?
Since doing it wrong will damage the batteries: Is Tesla better off handling it all for you or take the responsibility for warranty and bad publicity when you or someone else damages their car or creates a bad experience for themself and whines about it on the intertubes.
If the recent fiasco in Chicago is any example, clearly there are a lot out there who are quite clueless.

 

[Genie]

Yes, but are you sure that you (and the millions of others who would get access to doing things themself) actually know how to do things yourself with batteries?
Since doing it wrong will damage the batteries: Is Tesla better off handling it all for you or take the responsibility for warranty and bad publicity when you or someone else damages their car or creates a bad experience for themself and whines about it on the intertubes.
If the recent fiasco in Chicago is any example, clearly there are a lot out there who are quite clueless.

They could easily allow the driver to initiate the battery heating, and the car allows it within parameters to protect the battery.

 

[Earl]

They could easily allow the driver to initiate the battery heating, and the car allows it within parameters to protect the battery.

to what temperature? for Fast Charging or just level 2?
How often should the driver do it?
How long before arriving at the DCFC should you start? (ie how long will it take?)
Remember that being hot for longer time wears on the battery.
This also all varies with battery type and age.
. . .
We just don't know enough. Not even I do

 

[DuncanM]

to what temperature? for Fast Charging or just level 2?
How often should the driver do it?
How long before arriving at the DCFC should you start? (ie how long will it take?)
Remember that being hot for longer time wears on the battery.
This also all varies with battery type and age.
. . .
We just don't know enough. Not even I do

Tesla does it in the EU, when you navigate to a DCFC so they already know how to implement battery heating for CCS DCFCs.

 

[Earl]

Tesla does it in the EU, when you navigate to a DCFC so they already know how to implement battery heating for CCS DCFCs.

That's different from being able to manually push a button to start your car preconditioning to DCFC.

 

[DonTom]

Yes, but are you sure that you (and the millions of others who would get access to doing things themself) actually know how to do things yourself with batteries?

We should be able to have it activate with manual control and still let the FW have enough idiot proofing to not damage the battery or anything else.

-Don- Reno, NV

 

[DonTom]

That's different from being able to manually push a button to start your car preconditioning to DCFC.

Different yes, but also useful enough.

-Don- Reno, NV

 

[Earl]

We should be able to have it activate with manual control and still let the FW have enough idiot proofing to not damage the battery or anything else.

-Don- Reno, NV

What if the best policy is to start pre-heating for Supercharging is to know:
- the current battery temperature
- the charging rate at the Supercharger you're going to
- the thermal inertia of the battery, hence; how long it will take to get from the current temperature to the optimal Supercharging temperature
- the estimated time to get to that Supercharger
- that being at the pre-heated state for longer time will decrease the life of your battery

then:
- carefully compute when you should start pre-heating so it can remain at the pre-heated state for as little time as possible

How are you going to do better?
Should Tesla warranty your battery if you don't this (ie are an 'idiot' to use your word) do better?
Can you come up with a better idiot-proof approach while still providing optimal Supercharging speeds?