preconditioning and regen braking

[DB288]

many posts but not totally clear…

in garage plugged in…

precondition for a time…

get car…it’s warm …unplug…

pull out …regen braking not limited…

with 5 min of driving it is limited again…

it’s about 40F out…not really cold…
——-

with a cold start…from garage and ?40-50F

starts with regen braking limited…and it stays limited…

it does not seem to warm up…

———

how do i know it’s not broken (new MY)…

i never seem to get full regen

it’s not that cold where i live

 

[Buckeye614]

Yeah it's 45-55 here and I see regen limited after driving for a bit. (also garaged). I only charge to 80%. I hear it tends to be more limited when it's closer to fully charged. I am waiting until it's summer time to see if I still get the regen limited light before I contact Tesla.

 

[Hamtaro7]

why dont u use the option to have the brakes kick in when limited?

 

[240vPlug]

Precondition doesn't save any energy. It's normal for it to be limited.

What I have observed is that sustained temps under 60F will cause Regen to be limited for a time. The colder it is the more limited it will be. Also, higher states of charge will also further limit Regen. For example 90% vs 80% will result in it being more limited.

This is a common complaint with Tesla. Just set the option to engage friction brakes when Regen is limited or allow more time for stopping when you see the dotted bars on the left of the energy meter/bar.

 

[avs007]

It's completely normal. I live on a hill, so I deal with this every day. My garage is fully finished/insulated, so even when the temps in the garage are < 55 degrees or so, I'll notice the reduced regen. I'll probably notice it more than most people, because I live on a hill. Reduced regen might still be enough to slow you down on flat terrain, but it isn't going to do squat going down a 10-12% grade. I just use scheduled departure. That warms the battery enough, that I have decent regen to make it down the hill without having to use the brakes much. If I turn on climate manually, depending on how cold it is, I have to do this up to an hour before I leave to have enough regen to make it all the way down the hill. Otherwise it will crap out halfway down.

As far turning on friction brakes... I would only do that if you live somewhere flat... Otherwise, I wouldn't want the thing to ride the brake going down said 10-12% incline. I'd rather be aware of what my regen is, and drive accordingly.

 

[DB288]

why dont u use the option to have the brakes kick in when limited?

i want to use the regen braking…to save energy and to save my brakes…that’s the fun of having the tesla for me…

they say condition it and it will be full regen …but it’s not…is it broken? i charge to 90%…how it was rwjsb l picked it up..,

 

[coleman567]

i want to use the regen braking…to save energy and to save my brakes…that’s the fun of having the tesla for me…

they say condition it and it will be full regen …but it’s not…is it broken? i charge to 90%…how it was rwjsb l picked it up..,

Your garage sounds like it is warmer than the outside temperature, which is what is causing you to lose regen after you've left and have been driving in cold temps.

 

[Goobers]

Yeah, it's pretty cold here too, so I've been constantly getting limited regen braking.

But ya know... even if it's fully working, just how much do you expect to get from it anyway?

I'll chalk it up to a "plus" if I get some and "meh, whatever" if I don't. And just enjoy my brand new, but dirty AF MYP anyway.

 

[240vPlug]

i want to use the regen braking…to save energy and to save my brakes…that’s the fun of having the tesla for me…

they say condition it and it will be full regen …but it’s not…is it broken? i charge to 90%…how it was rwjsb l picked it up..,

I understand as I like to save energy as well. Conditioning the car though doesn't save any energy....it probably uses more energy due to losses. There is nothing wrong with the car. Try reducing the charge limit from 90% to 80% and that may help. Otherwise, just get in the car and drive it. That will use the least amount of energy and once you drive for a bit regen will increase.

If you leave the same time every day you can use the departure feature. The only time you need to precondition is if your going on a road trip and you want to warm the cabin so that you can leave with max power in the battery.

 

[jcanoe]

i want to use the regen braking…to save energy and to save my brakes…that’s the fun of having the tesla for me…

they say condition it and it will be full regen …but it’s not…is it broken? i charge to 90%…how it was rwjsb l picked it up..,

As noted to ensure adequate regenerative braking is available trying charging to less than ~85% each day. In my experience when you charge above ~85% regen may be limited. The other thing that can happen is that the Tesla Model Y's thermal management system is taking some of the heat from the battery to warm the passenger cabin. This would cool the battery to the point that regenerative braking might be reduced (not fully eliminated.) Combining the effect of a mostly full battery with a cooler battery would reduce the available regenerative braking.

The ability to blend the friction brakes when regenerative braking is reduced is one of the best driving enhancements Tesla has made to the Model Y. You can observe when you raise your foot when regenerative braking is active (usually for up to 50% of the braking force being applied) and when friction braking takes over for any additional braking force being applied.

 

[nate704]

It is Tesla software engineers' gift to the owners, so that the surface of the rotor and brake pads can be cleaned.

 

[240vPlug]

It is Tesla software engineers' gift to the owners, so that the surface of the rotor and brake pads can be cleaned.

Yes exactly. They need to get some use. This way you know they are still working when you may need them.

 

[jjrandorin]

i want to use the regen braking…to save energy and to save my brakes…that’s the fun of having the tesla for me…

they say condition it and it will be full regen …but it’s not…is it broken? i charge to 90%…how it was rwjsb l picked it up..,

Preconditioning your car to try to warm your battery to use regen braking is not saving energy in the slightest. The energy to pre condition the battery has to come from somewhere, so preconditioning just to get regen doesnt save anything.

No, its not broken. yes, your battery is cold, Full regen needs a warm battery and "its 70 degrees outside here" is not "warm battery for full regen.

 

[bluenycom]

I think there is a confusion using the term "precondition" as it's being used in different setting per Tesla.
1. Precondition before supercharge - this is to prepare the battery (usually warm it up) using its own electricity so it can handle large amount of electricity transfer from DC fast charger.
2. Precondition departure setting in home charging (Level 2) - this is to use shore power (home electricity) to warm up the vehicles for YOUR comfort. If you park outside and it's really cold then it would warm the battery too using shore power. This way, it's "saving" power from the battery for later use when you're unplugged.

I haven't said anything about regen because it depends on how cold or how much charge you had when you unplugged and leave your warm garage.

 

[jcanoe]

Precondition departure setting in home charging (Level 2) - this is to use shore power (home electricity) to warm up the vehicles for YOUR comfort. If you park outside and it's really cold then it would warm the battery too using shore power. This way, it's "saving" power from the battery for later use when you're unplugged.

You can precondition the Tesla Model Y while the Model Y is parked whether or not the Model Y is plugged in. Power for preconditioning always comes from the battery *. If the Tesla Model Y is plugged in the the power drawn from the battery can be replenished from the grid in a short amount of time (assuming Level 2 charging) or a longer amount of time (Level 1 charging.)

* The wiring of the Tesla Model does Y not include separate high voltage wiring from the on-board charger to the high voltage HVAC compressor (used for heating and cooling) or to the front and rear drive unit motors (stator heating is used to warm the battery as required.) The wiring path is from the grid to the on-board charger electronics to the high voltage battery. During preconditioning the high voltage battery supplies the power for the drive units (for stator heating) and the HVAC compressor. Under some conditions the power demand while preconditioning(14kW+) can be much greater than the maximum power available from the grid (11.5kW).

 

[Brian-MS90D]

Charging to 90% in sub-50F weather is going to result in a lot of limited regen. No way around that.

I like regen too. For daily driving, in the winter I only charge to 50% - 60%. This helps available regen A LOT. Obviously, this would not be a solution if you need to drive more than that in a day.

Amount of available regen will dynamically change as you drive too. For example, if you go down a looong steep hill, then your regen will be dramatically limited for a time until the battery can safely accept more.

And, even limited regen in a MY is better (stronger) than the old days when regen was limited in an older MS!

 

[patmurphey]

i want to use the regen braking…to save energy and to save my brakes…that’s the fun of having the tesla for me…

they say condition it and it will be full regen …but it’s not…is it broken? i charge to 90%…how it was rwjsb l picked it up..,

There are circumstances where regen is not available that are not "malfunctions". You can select the option for the car to automatically use brakes to give the same one pedal feel in those circumstances only. The option is totally transparent, and you don't have to worry about unavailable messages.

 

[avs007]

Preconditioning your car to try to warm your battery to use regen braking is not saving energy in the slightest. The energy to pre condition the battery has to come from somewhere, so preconditioning just to get regen doesnt save anything.

I don't think he's talking about saving energy overall, I think he's talking about saving energy as in his battery SoC while he's driving to his destination. I easily gain an addition 2% SoC just going down the hill where I live. And it definitely saves your brakes, especially if you have to regularly descend a steep road. The roads on our hill are 10-12% grades depending on which road you take. In an ICE I normally use low gears going down the hill. In the Tesla, if I'm not able to use regen, you'll have to stand on your brakes going down the hill if you try to descend at the speed limit (35-45mph)