What devices stay on when charging?

[Manbutter]

I baby my battery. Never used a Supercharger. Charge to 52% daily, max charge at 80% for long trips, set home charge rate at 12a (initially 5a).

It is on this last point I have a question: people tell me I’m wasting power this way because the car stays “awake” and on while charging. (So the longer it takes to charge, the more wasted energy.) I DO hear whirring and mechanical noises as I charge. Can someone list the devices that are on when I’m charging?

Only thing I can think of is the battery warmer.

 

[Manbutter]

Also, what is the charge rate during regen braking? I have to imagine it’s as high as a supercharger.

 

[Sophias_dad]

You'd have to ask Tesla what the precise list of components that might run while the car stays awake for charging. Whatever devices they are, its a 250-300W tax on your charge. Your friends are absolutely correct, you are wasting tons of power charging at such a low rate, and the batteries will do no better at 12A than 48A, its all 'slow' to them.

https://www.reddit.com/r/teslamotors/comments/b4q8lx

seems to suggest regen is limited to 75kwh, which is considerably more than I would have guessed.

Apparently you can rejoice, for Tesla "Low" Regenerative Braking Coming Back (It Seems) - CleanTechnica suggests the lower regen option is coming back, so you'll be able to burn off brake pads instead of recharging your battery.

I gotta ask... how many miles on your Y and how is your 100% charge holding up? Do you think your charging/usage habits have an effect?

 

[BobHinden]

I baby my battery. Never used a Supercharger. Charge to 52% daily, max charge at 80% for long trips, set home charge rate at 12a (initially 5a).

I think you are being way too conservative with your battery.

I have a 2018 M3 LR, my charging protocol is to charge to 90%, 95% to 100% before a long trip, and don't charge until I am below about 100 miles of range. I charge at home, only use superchargers when traveling.

The car is more than five years old now and most of the battery capacity is still there. Maybe 10% less than I when I first got it.

Tesla's battery systems are very robust.

 

[jcanoe]

I baby my battery. Never used a Supercharger. Charge to 52% daily, max charge at 80% for long trips, set home charge rate at 12a (initially 5a).

It is on this last point I have a question: people tell me I’m wasting power this way because the car stays “awake” and on while charging. (So the longer it takes to charge, the more wasted energy.) I DO hear whirring and mechanical noises as I charge. Can someone list the devices that are on when I’m charging?

Only thing I can think of is the battery warmer.

When charging there are overhead losses (mostly heat) that varies between almost 20% (Level 1, i.e. 120V) and as little as 5% (Level 2, i.e. 240V). The most efficient strategy, when charging, is to complete charging as quickly as possible.

Some test results have shown that the most efficient 240V (Level 2) charging rate is 40A. Charging at 48A may be slightly less efficient as there is additional heat loss in the wiring and the on-board charging circuitry, possibly some additional cooling of the charging electronics and battery. Charging at 32 amps takes 25% longer than 40A for the same charge. (I am set up to charge at 240V and 32A at home. Usually charge my 2020 LRMY at ~200V and 30A at a public Level 2 charging station.)

 

[ucmndd]

The whole car stays “awake” basically.

MCU
Power Conversion System
Coolant pumps / fans

Your regimen is well beyond pedantic and has negligible to absolutely zero effect on battery health - to the detriment of other systems.

PCS was an early weak spot on the 3/Y and they still are one of the parts more prone to fail.

Coolant pumps and fans are mechanical and absolutely have a finite life.

Best case - you’re wasting fantastic amounts of energy over the life of the car for absolutely no benefit.

 

[Manbutter]

You'd have to ask Tesla what the precise list of components that might run while the car stays awake for charging. Whatever devices they are, its a 250-300W tax on your charge. Your friends are absolutely correct, you are wasting tons of power charging at such a low rate, and the batteries will do no better at 12A than 48A, its all 'slow' to them.

https://www.reddit.com/r/teslamotors/comments/b4q8lx

seems to suggest regen is limited to 75kwh, which is considerably more than I would have guessed.

Apparently you can rejoice, for Tesla "Low" Regenerative Braking Coming Back (It Seems) - CleanTechnica suggests the lower regen option is coming back, so you'll be able to burn off brake pads instead of recharging your battery.

I gotta ask... how many miles on your Y and how is your 100% charge holding up? Do you think your charging/usage habits have an effect?

I only have 3400 miles on the car. I would say that I’ve lost about 3% battery life. It’s noticeable but not significant. Unscientific but my usual daily route used to take me from 52% to 44% when brand new. But now it takes me from 52% to 42-43%. Can’t really say if my regimen has done anything.

One of the best features of ev’s is the regen and single pedal driving. I couldn’t switch to lower regen even if option was available. I hate it when the system restricts the regen. I love being able to hardly use the brakes more than once or twice on 15 mile trips.