Charger switching on-off every hour after charge in complete

[elektrinis]

Just bought an european 2021 model 3. Was charging over night (-5C here) and noticed that after it charged, it was still cycling the charger every hour for 5 minutes, taking 0.8kWh each time, which equates to 800W constant draw.

What the hell? Why is it taking so much power when just sitting there? My whole 200m2 house takes less power to keep warm.

Is it heating the battery overnight?? How do I disable this "feature"?

 

[cgell]

Are you using a third-party app that is maybe waking the car every hour and telling it to precondition? (Maybe it’s not even set to do that, but is doing so in error.) If so, see if logging out/removing the app helps.

.8kWh in just 5 minutes is around 9,600W if I am calculating correctly.

 

[elektrinis]

I am not using an app, the car is not connected. I am only logging my power consumption.
Yes it charges at 10kW for those 5 minutes, and swithes off for the rest 55 minutes. Which gives 0.8kWh per hour, o r just 800W average.

Precondition is off, and even if it was on, I don't see why it would heat it all night insteaf or right before the set time.
By the way Sentry was enabled, so maybe that's that. But it's still ridiculous to take 800W instead of 15-20W that video recording actually needs.

 

[LoudMusic]

I am not using an app, the car is not connected. I am only logging my power consumption.
Yes it charges at 10kW for those 5 minutes, and swithes off for the rest 55 minutes. Which gives 0.8kWh per hour, o r just 800W average.

Precondition is off, and even if it was on, I don't see why it would heat it all night insteaf or right before the set time.
By the way Sentry was enabled, so maybe that's that. But it's still ridiculous to take 800W instead of 15-20W that video recording actually needs.

There are six cameras and the processing for motion detection and recording it and communicating with Tesla servers. It certainly shouldn't be 800w but it's a heck of a lot more than 20w draw.

I believe it does try to keep the battery above freezing. And it's a giant block of metal so that likely does take quite a bit of energy.

 

[elektrinis]

There are six cameras and the processing for motion detection and recording it and communicating with Tesla servers. It certainly shouldn't be 800w but it's a heck of a lot more than 20w draw.

I believe it does try to keep the battery above freezing. And it's a giant block of metal so that likely does take quite a bit of energy.

Lithium batteries should be ok up to -20C with limited power. And I for sure don't need all 350kW on icy road.
Only for charging you need it above freezing.

To compare, I have a celeron server at home with EIGHT 4k cameras, doing motion detection and object retection. Also RAID5, running home automation, file sync with multiple PCs. It draws 20W.

All in all, 800W is a huge deal, this adds up to 600kWh per month. Just by being plugged in.
I'm not even complaining that it does not apply mechanical brakes when regen is not available. Yet.
Really bad experience so far.

 

[jjrandorin]

By the way Sentry was enabled, so maybe that's that.

Having Sentry mode on uses 1-2 miles of range (1.5 - 3kms according to an online calculator I just used) per hour of usage. This usage is because the car doesnt sleep while sentry mode is on. Standby summon also keeps the car awake.

Any discussion of power usage while sitting that includes "sentry mode was on", has the answer to "why is my car doing X" related to power drain, in the discussion already.

 

[elektrinis]

Having Sentry mode on uses 1-2 miles of range (1.5 - 3kms according to an online calculator I just used) per hour of usage. This usage is because the car doesnt sleep while sentry mode is on. Standby summon also keeps the car awake.

Any discussion of power usage while sitting that includes "sentry mode was on", has the answer to "why is my car doing X" related to power drain, in the discussion already.

So you are saying it's just a bad design that some cameras somehow force it to use 800W on average?
I hope I have not triggered anyone.

 

[jjrandorin]

So you are saying it's just a bad design that some cameras somehow force it to use 800W on average?
I hope I have not triggered anyone.

I am saying that you need to turn off sentry mode, and standby summon, and anything else that will prevent the car from sleeping, then look at any usage after that. Sentry mode prevents the car from sleeping, so it will use 1.5 to 3kms and hour. Its not the cameras using that, its the car staying awake, similar to a computer either being put to sleep or running at the desktop.

The charging is likely coming because of the drain from the car not going to sleep. If you want to consider sentry mode keeping the car awake bad design, go right ahead. I thought you wanted an answer to "why is my car charging so much during the night", not a discussion on bad design.

 

[LoudMusic]

So you are saying it's just a bad design that some cameras somehow force it to use 800W on average?
I hope I have not triggered anyone.

I think you've only triggered yourself.

 

[rrolsbe]

I have not experienced your charging scenario but from what I have read here goes. Two or three years ago, if plugged in, the car would top off the battery when the charge level dropped by about 3%, I believe that has changed. Now if the car is plugged in and scheduled/departure charging is not being used the car might wake up every hour to top off the battery. This could potentially be very power wasteful when the temps are below freezing; likewise, if the car enters sleep state between these hourly topoffs, the HV contactors would also cycle each time. I suspect a good part of the 800W used is for heating to allow hourly topoff of a cold HV traction battery. As far as the power used when sentry is enabled, most of that power is because the car must be awake which appears to draw between 200-250W. The actual power to the cameras and the processing is probably a very small part of that power usage.

 

[elektrinis]

I am saying that you need to turn off sentry mode, and standby summon, and anything else that will prevent the car from sleeping, then look at any usage after that. Sentry mode prevents the car from sleeping, so it will use 1.5 to 3kms and hour. Its not the cameras using that, its the car staying awake, similar to a computer either being put to sleep or running at the desktop.

The charging is likely coming because of the drain from the car not going to sleep. If you want to consider sentry mode keeping the car awake bad design, go right ahead. I thought you wanted an answer to "why is my car charging so much during the night", not a discussion on bad design.

Yes, I asked why it is using so much power, and you have not answered. Cameras don't use this much of energy, "being awake" as well. The only explanation would be if battery was being constantly heated. And if it is, it's a bad design. Battery does nott need to be warm to use cameras. It's not even needed for driving.

 

[jjrandorin]

Yes, I asked why it is using so much power, and you have not answered.

Yes I did (multiple times actually). Yes, "being awake" does use that much power, because being awake drains the battery faster, then your charging station charges the lost energy from being awake back to the battery.

Having Sentry mode on uses 1-2 miles of range (1.5 - 3kms according to an online calculator I just used) per hour of usage. This usage is because the car doesnt sleep while sentry mode is on

I am saying that you need to turn off sentry mode, and standby summon, and anything else that will prevent the car from sleeping,

In any case, I wish you the best in figuring out an answer that works for you.

 

[ucmndd]

Yes, it’s Sentry. If you don’t like this behavior and power consumption you should turn it off.

As to “bad design” - The car’s hardware was never designed for Sentry mode, it was designed for autonomous driving. Sentry is a complete afterthought. When it’s running the car is “on”, using the MCU and Autopilot computer just like it would be if you were driving down the highway. It was never designed for efficiency but rather the compute power necessary for autonomous driving.

It doesn’t much matter how much you “think” the cameras should use. This is what they do use.

 

[ucmndd]

A follow up, this isn’t entirely due to Sentry - the short duration charging sessions are incredibly inefficient, resulting in losses on top of losses. If you don’t like the “top up every hour” behavior but still want to keep sentry on, you should enable scheduled charging. That will let the battery run down farther and wait until the next scheduled charge time to top off. You’ll still be losing ~1% every hour or two.

 

[elektrinis]

Listen. I get it. Sentry mode causes a chain of events that ends up eating 800W. But my last question was WHY, and you seem to go in circles and not answering this. Perhaps someone else, with some technical knowledge, knows.

I will do another charge this night to test with sentry off.

 

[rrolsbe]

A follow up, this isn’t entirely due to Sentry - the short duration charging sessions are incredibly inefficient, resulting in losses on top of losses. If you don’t like the “top up every hour” behavior but still want to keep sentry on, you should enable scheduled charging. That will let the battery run down farther and wait until the next scheduled charge time to top off. You’ll still be losing ~1% every hour or two.

Yeah I think you are correct, the reason the car is topping off every hour is because the car is awake due to Sentry Mode being activated. If the car is not awake and plugged in, at what level of charge drop does it top off? still around 3%?

 

[ucmndd]

Listen. I get it. Sentry mode causes a chain of events that ends up eating 800W. But my last question was WHY, and you seem to go in circles and not answering this. Perhaps someone else, with some technical knowledge, knows.

I will do another charge this night to test with sentry off.

“WHY” has been answered multiple times in this thread by multiple different people. Do you not like the answer or are you just not reading it?

 

[elektrinis]

“WHY” has been answered multiple times in this thread by multiple different people. Do you not like the answer or are you just not reading it?

Where are 800W wasted exactly? Which component consumes such high energy, and why exactly, and how is such waste of energy justified? "Car being awake" is not an answer, it's incompetency.

 

[ucmndd]

Where are 800W wasted exactly? Which component consumes such high energy, and why exactly, and how is such waste of energy justified? "Car being awake" is not an answer, it's incompetency.

As to “bad design” - The car’s hardware was never designed for Sentry mode, it was designed for autonomous driving. Sentry is a complete afterthought. When it’s running the car is “on”, using the MCU and Autopilot computer just like it would be if you were driving down the highway. It was never designed for efficiency but rather the compute power necessary for autonomous driving.

A follow up, this isn’t entirely due to Sentry - the short duration charging sessions are incredibly inefficient, resulting in losses on top of losses. If you don’t like the “top up every hour” behavior but still want to keep sentry on, you should enable scheduled charging. That will let the battery run down farther and wait until the next scheduled charge time to top off. You’ll still be losing ~1% every hour or two.

Let’s try again, bolding the relevant info.

Sentry is an alarm system hack utilizing an autonomous driving computer and sensor suite. It was designed and released well after the hardware was designed for this completely different purpose. That’s why it uses so much energy.

As I said, you can like that answer or not, but it’s the only correct one and multiple people have explained it to you.

 

[Tam]

Where are 800W wasted exactly? Which component consumes such high energy, and why exactly, and how is such waste of energy justified? "Car being awake" is not an answer, it's incompetency.

Trickle charge does not happen if the State of Charge stays the same. When there's consumption that draws the battery down, that's when a trickle charge happens.

Sentry mode keeps the car awake. "Awake" here means the electronic components are not shutting down; they are still on and consume energy.

I think you know the answer to why the car keeps on doing a trickle charge but you just want to point out that trickle charge is incompetency.