This is exactly what happens to me when I set off for the Ipswich chargers! Even a 15 mins preconditioning warm up leaves the charge rate pathetic! With a battery at 11% on arrival it was only taking a poor charge rate at a 250kW charger 😕.

Lawrence

 

I am lucky in that my parents' driveway is reasonably sheltered and private so I just popped the phone in and set the car's nav to the chargers and in effect started the journey and the SC precon kicked in straight away, I left it for 15 mins and the drive there is 15 mins and that seemed enough combined to get it up to temp on a fairly warm day so that it kicked in to the expected rate for the percentage. But yeah, slightly annoying if it isn't possible to kick off SC precon before leaving.

 

We had a mild night last night; the preconditioning was running through the whole 15 minute journey to Ipswich - so I was annoyed when the charging started at a sad level and the notification came up telling me that it was preconditioning the battery to improve the charge rate .... With a level of 12% after a short time, it was charging at ~90kW at a 250kW charger on a mild day after 20 minutes pre-con. It eventually got up to 150kW for a short time before dropping off fairly quickly to ~100kW and then slower as it grudgingly reached 50% or so. I ended it at 89% to return home - and finished it off to 100% overnight.

Lawrence

 

Almost all of the battery heating during the "precondition for SC" option comes from the drive motor(s). Tesla switch the motor controllers into a far less efficient operating mode so that they make the motor(s) generate a lot of heat, which is then used to warm up the battery pack. If you don't drive the car for very long the battery won't warm up much.

 

That's interesting, thanks for that Jeremy

 

Ah, that wonderful phrase 'very long'. 50 sec? 5 mins? 15 mins? 120 mins? I don't recall seeing any actual time suggested in the manual. On my 15 mins journey, pre-con was not running the whole time.

Lawrence

 

IIRC Tesla used to suggest doing this 30 minutes before arriving at a SC, so presumably that's about how much driving time it takes to get the motor(s) to produce enough heat to make a useful difference in charge performance.

 

Next time I'll ensure a full 30 mins pre-con.

Lawrence

 

The motors can shoot up to over 60c very quickly by drawing lots of power (I've been monitoring via S3XY app) it's the battery that takes ages to heat up. It's a HUGE thermal mass after all.

The amount of power that you can dump into the battery is also dependent on motor count. Dual motor has twice the heating capability.


I would have thought, if it bothers you, you could sit in the car parked while navigating to SuC to heat up the battery. I once arrived at a SuC 5min before off-peak pricing. I sat there in P and found if I set sat-nav to any other destination, battery heating stops. But if I set nav back to SuC I'm at, battery heating comes on again.

For Lawrence's LFP battery, worth keeping in mind Tesla SuC can now somehow heat it up whilst charging:

Tesla LFP Batteries Can Now Be Warmed up While Supercharging Using Innovative Feature

Tesla unveils another charging imrpovement - Superchargers can now heat the batteries of LFP vehicles to help them charge faster.

www.notateslaapp.com

 

So I'm wondering if the following might work Lawrence.

Go to your car with one of your key cards, get in, navigate to the SC, the precon should start (you may have to go into drive/reverse first I cant recall), leave the key card on the centre console in the correct location (different on Highlands I believe), get out (car will auto park at this point whatever) and go back inside. Open phone app and lock the car remotely with the key card inside. Make a nice cuppa, take your time enjoying it, after about 20 mins or so, leave the cup for the missus to wash up (it is her job after all ) go to the car with your phone, jump in and away you go to the SC.

Not sure whether or not the car will shutdown when remotely locked though. I would try but we've had quite the evening at Chez Scorzon with the plod breaking into the neighbour opposite's house coz they thought he might be dead inside (he wasnt there) and then 10 mins later another neighbour knocking on the door telling me one of our cats was dead after an RTA (it wasnt ours) and I then had to help clear the poor wee beast up and then hand the poor thing over to its distraught owners.

Wine now in hand and disappearing fast.

 

we've had quite the evening at Chez Scorzon with the plod breaking into the neighbour opposite's house coz they thought he might be dead inside (he wasnt there) and then 10 mins later another neighbour knocking on the door telling me one of our cats was dead after an RTA (it wasnt ours) and I then had to help clear the poor wee beast up and then hand the poor thing over to its distraught owners.

Have I stumbled into a briefing session of the next Eastenders script brainstorming suggestions?

 

Leave it you slag!!

 

Now, do I let my better half read this?...... In fact, I wondered about longer preconditioning but the battery was at 11% (deliberately) to ensure faster charging (or so I thought), and I wasn't certain that it might get too low to go to Ipswich. That would not have been a problem because I can charge at home, but its still free for me at Ipswich so 10% to 90% would be good. Next time I'll do it properly.

Lawrence (who had his wine on Friday).

 

I think @Lawrence H that as mentioned above the normal precon for driving will only lift it to 20C perhaps. If you are only a few minutes slow driving to your local SC the car might still not have time to get you up close to optimum charging temps.

It would definitely help no doubt. I am going to try my theorised key card solution right this minute. Standby for the usual disappointment ensuing whenever I try some half baked ill thought plan based on zero scientific fact. Oh no sorry, that's work, got myself confused for a moment there. This is unpaid Muppetry on my own time.

 

or, as a last resort, use the app to set departure time for the S/c allowing 30 mins or so .

Lawrence 🚗

 

It’s crazy they don’t just give you the option with all the other tiny niche changes they like to put out. It feels a bit like the scheduled charging where you couldn’t easily set a start and stop time for years until they finally relented, just give us an option to heat the battery on demand.

 

Yes, exactly!

Lawrence

 

One thing to bear in mind, Lawrence, is that I think you have a standard RWD car with LFP? In that case, your car only has the one motor to help with Pre-conditioning for SuC. That's generates around 3kW heat output, but its trying to heat a 4-500kg lump of battery to increase its temperature by 40 degrees or so. That's a big ask in 15 mins. If you had a dual motor it would perhaps be a little quicker with both motors assisting the heating - those with Scan My Tesla will see that preconditioning can use 7kW on a dual motor car, which must help with keeping the inlet temperature up and heating the battery.

All that said, it would be nice to have a manual pre-condition the battery option you could set going for a 1/4 hour before you leave. It's kind of a bit niche from Tesla's perspective though, cos Suc is intended for long highway journeys, where you have charged at home first and then stop a couple of hours+ into your journey to SuC. That's why its always recommended when you're travelling distance to supercharge at the end of a journey when battery is warm and probably pre-heated rather than waiting overnight to do it in the next day before you set off again.

 

Irrespective of heating for supercharging it would be nice to be able to heat the battery for driving if nothing else. Get the battery to 20-25 deg C before departure, then you’re half way to a supercharging temp and have regen etc. it currently only seems to heat the battery if it’s freezing

 

Slightly puzzled here: the app (and touchscreen) includes 'schedule' so we can indeed pre-heat the battery before setting off. I don't know what the actual consumption is for pre-heating but for most journeys in mild weather I don't bother. If taking family somewhere I set schedule so that the car etc is ready. You clearly do need to schedule for proper pre-con heating before s/c. It was the fact that I had let the SOC drop to 11% that cautioned me against a scheduled pre-heat for the s/c. I think that I should have gone ahead and pre-con heated anyway. The car does warn you if there isn't enough power to get to the s/c so I could easily have charged at home enough to get me there.

Lawrence

 

You can set it to preheat the cabin, not the battery. The battery heater may also come on at the same time but that’s at the discretion of the car

 

Yes, I know. But you can also set it to preheat the battery: check the app - schedule - precondition.

Lawrence

 

You know if the battery is pre-heating when you turn on pre-conditioning before leaving on a journey, as the Tesla app will show three red bacons (same as heated seats have) next to the battery icon in top left of the app. You will hear the heating running as it will be pre heating / cooling the cabin. The scheduled preconditioning is aimed at making the cabin comfortable before starting a journey. It will possibly heat the battery up too, but only to efficient driving temperature not SuC temperatures.

 

That does preheat the battery, but only in extreme cold if battery is stone cold probably in Norway winter. Not in UK cold parked just overnight.

 

Hmmmm. Are you sure? I have activated this and heard the heating system start when expected. Yes, in normal weather.

Lawrence

 

I am only as sure as the data I see. TeslaMate records battery heating as 1 or 0 when charging. I've not seen it turn on during coldest days I think it should turn on.

I have an automation to run it automatically I originally thought would be helpful:
when: 2 hr before end of cheap period.
condition: if below freezing, if plugged in
action: call start preconditioning

The heating system sounds could also be just for heating cabin?

Only way to be sure is to monitor battery coolant inflow temperature and see if it is above battery temperature.

 

Next time I will check this carefully. I am 90% sure - not 100%! When I use it I don't get the icon about temperature problems - otherwise I often do.

Lawrence

 

Much as I am fascinated to see the intimate details including coolant temperature - I don't have any extra facilities to monitor these, so its icons or nothing .

Lawrence

 

May be LFP are more sensitive to low temperature so minimum heating happens during scheduled pre-con to keep it out of low temperature area?

The car has a lot of temperature ranges. For my monitoring of my NMC battery, it seems to be happy for driving around at around 10c and would only heat up battery when there's unused excess heat.

There may also be software logic that differentiates between plugged in or not. As in enable battery heating to higher temperature if plugged in. If not plugged in, only heat to minimum temperature out of "temperature problem" zone.

One thing I'm certain, the temperature problem icon disappearing is still very far from ideal SuC temperature.