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Scheduled Departure - does it warm the battery?
- Thread starter pdk42
- Start date
While I can’t say for certain, I can share what happened when I used it with temps below/around 0 Celsius on my a Model 3 SR+:
- scheduled departure for 5:30 AM
- starts charging at 4:50 AM at 2kW due to colder temps and colder battery (car was at 90% and had dropped to 87% overnight while waiting for charging to start)
- cabin preheat comes on at 5:15 AM.
- leave at 5:30 AM. Cabin is perfect, but still charging at only 2kW so my battery had only just ticked up to 88%, and instantly dropped down to 87% within a minute of driving. Regen was barely a cm on screen and I was notified that regen would be limited.
All in all, I think the car just didn’t account for the reduced charging speed. Had it taken that into affect then maybe I would have had full regen and preconditioned battery. I’m honestly also not sure why it didn’t account for that as it even warns you in app that colder temps will affect charging speed.
- scheduled departure for 5:30 AM
- starts charging at 4:50 AM at 2kW due to colder temps and colder battery (car was at 90% and had dropped to 87% overnight while waiting for charging to start)
- cabin preheat comes on at 5:15 AM.
- leave at 5:30 AM. Cabin is perfect, but still charging at only 2kW so my battery had only just ticked up to 88%, and instantly dropped down to 87% within a minute of driving. Regen was barely a cm on screen and I was notified that regen would be limited.
All in all, I think the car just didn’t account for the reduced charging speed. Had it taken that into affect then maybe I would have had full regen and preconditioned battery. I’m honestly also not sure why it didn’t account for that as it even warns you in app that colder temps will affect charging speed.
Jason71
Well-Known Member
I thought the M3 did not have a battery heater except the by virtue of using waste heat from the motors? In which case the answer would be no.
People seem to recommend timing charging to complete just before departure so that heat generated during charging pre-heats the battery to some degree.
People seem to recommend timing charging to complete just before departure so that heat generated during charging pre-heats the battery to some degree.
I'm sure I read somewhere that they use the rear motor as a heater by passing a small current through it but in such a way that it does not produce any torque. The coolant pump then circulates the heat generated through the battery. Devious.
Glan gluaisne
Active Member
The i3 does exactly the same. BMW explain that it does this in order for the car to know the actual charge rate available, by requesting charge for a short time and storing the charge point actual rating (without loading the CP all the car knows is the cable current capacity from the PP resistance to PE).
Once the car has stored the available charge current, it can turn the charge off and then determine when it needs to start charging in order to try to ensure that it's charged by the set departure time.
Temps here are also around the freezing point. I've been "manually" charging and heating the cabin an hour prior to leaving home (as I don't leave home at the same time everyday, so trying to schedule it with the car doesn't align with my actual drive) and still don't even have half of regen available when I leave an hour after I started the charge from 85% to 90%. Its annoying as I miss the one-pedal driving.
Not as good as I hoped here either.
I thought when using this mode the car would be much better for regen from the get go... but it really isn't. In these cold snaps i can expect my entire commute to work (10 miles) to be without any meaningful regen. Bit of a shame really.
My old ampera would have normal regen braking characteristics from first driving it even on cold days. Not sure how it would be able to do this?
Answering my own question... I used Scheduled Departure last night and I really don't think it made any difference to the regen available (which was almost non existent with the temperature when I left only just at zero). Pity.
mpandrew
Member
My hunch is the Ampera wasn't being so careful with the battery. You can absolutely pile a ton of regen energy back into a cold battery but it dramatically shortens its life. Be thankful that having to use some friction in the cold is saving your battery for the longer term.
Jason71
Well-Known Member
They did. its called Maxwell Technologies. It's not clear though if they bought them for the capacitors, the dry cell battery manufacturing tech or both though.
WannabeOwner
Well-Known Member
Scheduled Departure saved my bacon last night - given that I think its typical first-release-Tesla-buggy I'm surprised to be saying that!
Needed 100% charge for departure at 6AM, I figured (wrongly, as it turned out ...) that there was plenty of time after Midnight to complete the charge, so set Scheduled Start to Midnight (I have E7 tariff) and Scheduled Departure to 6AM.
Charge actually started at 23:10
and although it reached 100% by 6AM it had not finished balancing the cells (it togggled from 99% to 100% some time between 05:26 and 05:49, I stopped the charge at 06:04, so was probably "pretty much done")
Logging is patchy at home (Problem setting up WiFi just now) and logging failed between 5:26 (Climate was off then) and 5:49 (Climate was on by then). I had disabled all overnight TeslaFi schedules, so it was Scheduled Departure that turned Climate on.
Generally each logging gap was not more than 10 minutes, but with that proviso the Battery Heater did not come on. Regen severely limited because of 100% charge, so don't know if e.g. 90% charge would have had better Regen (maybe Battery heater would/could have come on)
Needed 100% charge for departure at 6AM, I figured (wrongly, as it turned out ...) that there was plenty of time after Midnight to complete the charge, so set Scheduled Start to Midnight (I have E7 tariff) and Scheduled Departure to 6AM.
Charge actually started at 23:10
and although it reached 100% by 6AM it had not finished balancing the cells (it togggled from 99% to 100% some time between 05:26 and 05:49, I stopped the charge at 06:04, so was probably "pretty much done")Logging is patchy at home (Problem setting up WiFi just now) and logging failed between 5:26 (Climate was off then) and 5:49 (Climate was on by then). I had disabled all overnight TeslaFi schedules, so it was Scheduled Departure that turned Climate on.
Generally each logging gap was not more than 10 minutes, but with that proviso the Battery Heater did not come on. Regen severely limited because of 100% charge, so don't know if e.g. 90% charge would have had better Regen (maybe Battery heater would/could have come on)
Ive watched a few videos on YouTube regards this and they say that it DOES pre warm the battery giving you full regen as regen is reduced with a cold battery
The Model 3 can intentionally use up to 7 kW of energy through the motors to produce heat for the battery pack. There are several videos of this online.
Initiating a preheat session in the app will also heat the battery pack. An audible whine can be heard from the front and rear motors during this process.
Preheating doesn’t warm it enough to provide full regen - only partial regen.
vitesse
Active Member
I believe the FIA regs do permit the use of capacitors for the Energy Recovery System (ERS) (as well as flywheels) but as far as I know the packaging and weight limitations in F1 cars mean that neither have been of practical use. The latest Mercedes technical information I read was that its power unit use a 20kg lithium ion battery pack,. That sounds tiny considering a Tesla pack is 25 times heavier, however it only needs to supply 120kW (160BHP) for 33 seconds per lap. Ultracapacitors have been used in other race formulas in hybrids, like the Le Mans winning Toyotas.
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