Keeping My Car Plugged In Charges It On And Off Throughout The Day. Is This Good?

[therealjimbob]

Hello,

I noticed by keeping my car plugged in throughout the day and set to 80% charge limit makes it so that the charger keeps charging the car throughout the entire day. Is this good for the car?

As you can see in the attached photo the spikes throughout the day are the car charging. I’m not sure if this is alright or will it mess my battery up.

 

[RayK]

No issue. Think about the power being provided to the battery with regen. I understand regen can generate 10's of kW to the battery in very small durations. Much more than what you see on the graph.

 

[jjrandorin]

Hello,

I noticed by keeping my car plugged in throughout the day and set to 80% charge limit makes it so that the charger keeps charging the car throughout the entire day. Is this good for the car?

As you can see in the attached photo the spikes throughout the day are the car charging. I’m not sure if this is alright or will it mess my battery up.

It normally would not cycle that much. Do you have sentry mode, or cabin overheat protection on or something?

 

[BitJam]

ABC: Always Be Charging. Tesla recommends charging every day.

Home Charging
What's a best practice for charging a Tesla at home?
We recommend plugging in every evening to top off the battery.

I have my car set to charge in the middle of the night even though the cost of electricity is the same. This way you only charge once per day and at a time when it's better for the grid. Both ways are fine; you are not damaging your car.

 

[P.S.S.]

Typically the more charge in a lithium ion battery, the higher the degradation rate. I charge every few days unless I’ll be driving a lot.

 

[therealjimbob]

It normally would not cycle that much. Do you have sentry mode, or cabin overheat protection on or something?

I do. I have both sentry and CHP enabled. The former because I live in a neighborhood where kids like to check door handles to raid your car and steal whatever’s in it.

I just wanted to be sure it wasn’t cycling too much. I thought that since it was plugged in, it would draw power from the outlet when in sentry mode etc.

 

[jjrandorin]

Typically the more charge in a lithium ion battery, the higher the degradation rate. I charge every few days unless I’ll be driving a lot.

Those little cycles the OP is charging will not do anything to their battery at all. Shallow charging is better than deeper charging, actually, so charging a lot, shallowly is better than "running it down to charge it back up".

Now, the contactors activating that much isnt necessarily the best, though.

 

[jjrandorin]

I do. I have both sentry and CHP enabled. The former because I live in a neighborhood where kids like to check door handles to raid your car and steal whatever’s in it.

I just wanted to be sure it wasn’t cycling too much. I thought that since it was plugged in, it would draw power from the outlet when in sentry mode etc.

If I were you, I would:

1. Turn off cabin overheat protection as that isnt needed in the slightest for the reason you specified (kids checking door handles), and is not necessary at all for the car electronics as some people seem to think. That feature was put in my tesla for "kids and pets" (elon's direct quote) and has nothing to do with protecting the cabin.

2. Set scheduled charging to the middle of the night, so that it charges any lost energy once in the middle of the night.

You are not hurting your battery charging like that, but there isnt any reason to activate the contactors that much, thats the part that would concern me (not hurting the battery) along with how much energy is being wasted / used.

24 hour sentry mode will put the equivalent of about 8-9k "miles" a year on your battery, just sitting there. If you drive 12k miles a year driving, using sentry mode 24/7 means your battery willl have 20k a year mile usage. That would bug me, but as long as you are aware of how much power you are using, its your choice to do it of course.

That doesnt count cabin overheat protection which probably will use slightly less than sentry, but estimate another 5-6k "miles" a year for that.

 

[P.S.S.]

Those little cycles the OP is charging will not do anything to their battery at all. Shallow charging is better than deeper charging, actually, so charging a lot, shallowly is better than "running it down to charge it back up".

Now, the contactors activating that much isnt necessarily the best, though.

I’m not talking about cycling, I’m talking about state of charge (SOC). If you have two identical lithium ion batteries and you left one with 80% charge and one with 20% SOC for a year, the 80% SOC battery would have degraded more than the other battery.

 

[jjrandorin]

I’m not talking about cycling, I’m talking about state of charge (SOC). If you have two identical lithium ion batteries and you left one with 80% charge and one with 20% SOC for a year, the 80% SOC battery would have degraded more than the other battery.

Yes, thats true.

 

[therealjimbob]

If I were you, I would:

1. Turn off cabin overheat protection as that isnt needed in the slightest for the reason you specified (kids checking door handles), and is not necessary at all for the car electronics as some people seem to think. That feature was put in my tesla for "kids and pets" (elon's direct quote) and has nothing to do with protecting the cabin.

2. Set scheduled charging to the middle of the night, so that it charges any lost energy once in the middle of the night.

You are not hurting your battery charging like that, but there isnt any reason to activate the contactors that much, thats the part that would concern me (not hurting the battery) along with how much energy is being wasted / used.

24 hour sentry mode will put the equivalent of about 8-9k "miles" a year on your battery, just sitting there. If you drive 12k miles a year driving, using sentry mode 24/7 means your battery willl have 20k a year mile usage. That would bug me, but as long as you are aware of how much power you are using, its your choice to do it of course.

That doesnt count cabin overheat protection which probably will use slightly less than sentry, but estimate another 5-6k "miles" a year for that.

Thank you for this info. I literally didn’t know all of these features drained that much of my battery. I’m gonna go ahead and exclude home for sentry mode and turn off cabin overheat protection. It’s winter anyway so it’s useless.

Let me ask you a question, if sentry mode is off and someone hits my car or try’s to break into it, will it still record a video clip or does that only work when sentry mode is turned on?

Thanks again for your answer. It was very insightful.

 

[jjrandorin]

Thank you for this info. I literally didn’t know all of these features drained that much of my battery. I’m gonna go ahead and exclude home for sentry mode and turn off cabin overheat protection. It’s winter anyway so it’s useless.

Let me ask you a question, if sentry mode is off and someone hits my car or try’s to break into it, will it still record a video clip or does that only work when sentry mode is turned on?

Thanks again for your answer. It was very insightful.

I believe it would only record a clip if sentry mode is on. Its actually not so much that sentry mode itself uses that much electricity, its that sentry mode does not allow the car to go to sleep at all. Car not sleeping = about 15-25 "miles" of usage every 24 hour period. Same thing with cabin overheat protection.

They do have their own energy use as well, and together those features use about 1.5 "miles" an hour (ish) of energy, on average.

As for the "catching video of people possibly breaking in the car", my question would be, suppose this actually did happen. You left sentry mode on, it got video of some random person breaking into your car. Then what? What are you going to do with that video, other than look at it and be mad? Are you expecting to take it to the police, and them say "Oh I know that person, let me go pick them up right now"?

This is a rhetorical question btw, but I am asking you what you plan on doing if you did capture something like this on video, and is whatever that is worth never allowing your car to sleep.

 

[Regaj]

I’m not talking about cycling, I’m talking about state of charge (SOC). If you have two identical lithium ion batteries and you left one with 80% charge and one with 20% SOC for a year, the 80% SOC battery would have degraded more than the other battery.

Depth of discharge is also a factor in Lithium-ion battery degradation. The typical ICE routine of periodically filling up, drawing down fuel over a few days, then filling up again when you're down to 1/4 tank isn't optimum for EV pack health.

 

[P.S.S.]

Depth of discharge is also a factor in Lithium-ion battery degradation. The typical ICE routine of periodically filling up, drawing down fuel over a few days, then filling up again when you're down to 1/4 tank isn't optimum for EV pack health.

Yes, I generally bounce between 80% and 25% SOC. With that being said, I only do that when it’s not an inconvenience to me. I’m not managing degradation to this degree if it impacts my convenience.

 

[therealjimbob]

I believe it would only record a clip if sentry mode is on. Its actually not so much that sentry mode itself uses that much electricity, its that sentry mode does not allow the car to go to sleep at all. Car not sleeping = about 15-25 "miles" of usage every 24 hour period. Same thing with cabin overheat protection.

They do have their own energy use as well, and together those features use about 1.5 "miles" an hour (ish) of energy, on average.

As for the "catching video of people possibly breaking in the car", my question would be, suppose this actually did happen. You left sentry mode on, it got video of some random person breaking into your car. Then what? What are you going to do with that video, other than look at it and be mad? Are you expecting to take it to the police, and them say "Oh I know that person, let me go pick them up right now"?

This is a rhetorical question btw, but I am asking you what you plan on doing if you did capture something like this on video, and is whatever that is worth never allowing your car to sleep.

Funny enough, I was thinking what you just said before I even finished writing it.

just turned sentry mode and overheat off today. I think that will make me sleep better at night vs sentry mode being on.

One more question though, you think I should keep it on away from home (like in parking lots and stuff) in case someone hits the car and don’t stick around (maybe it can get the license plate)? I know for some this may sound like a question that wouldn’t happen often, but I live in Baltimore, it happens more than you think.

I’m already thinking this may be a good idea considering on average I’m only away from my house for about an hour a day max.

 

[RayK]

I keep Sentry Mode enabled when not at home. So far, 100% of the clips are "false alarms" in that nothing has happened to my car. However, it does give me peace of mind that if something did occur, I might be able to capture identifying information (face, license plate, etc.). What use that information would be is certainly debatable but in my mind it's better than nothing. For me, the loss of range is a good tradeoff for (assumed) security.

Here in the SF Bay Area, I believe Sentry Mode was partially created due to the high amount of rear quarter window breakage / thefts that happened when the 3 was first introduced. There were many instances of media stories talking about how Model 3 was being targeted. After the release of Sentry Mode there was another stream of stories highlighting how the new tool was solving some crimes.

 

[804son]

An alternative to running sentry mode all the time at home and therefore not letting the car sleep. Would be to put up a security camera, video door bell, etc... Letting it capture the little buggers trying to break into cars. I'm not sure your saving any money, but the security camera or other will capture video for you even when your vehicle isn't there.

 

[jjrandorin]

Funny enough, I was thinking what you just said before I even finished writing it.

just turned sentry mode and overheat off today. I think that will make me sleep better at night vs sentry mode being on.

One more question though, you think I should keep it on away from home (like in parking lots and stuff) in case someone hits the car and don’t stick around (maybe it can get the license plate)? I know for some this may sound like a question that wouldn’t happen often, but I live in Baltimore, it happens more than you think.

I’m already thinking this may be a good idea considering on average I’m only away from my house for about an hour a day max.

I turn sentry mode on when I am parked away from home. My justification to myself for doing so is, it makes me feel a bit better, and it would also be proof for my own insurance company if I had a claim that should be under comprehensive rather than collision.