Scheduled Charging

[gnuarm]

The very fact that there is this conversation says the way Tesla has designed the scheduling control is messed up.

All they need to do is provide controls that do the simple things we need. Like have settings for start and end of peak times (two) and a control to disable charging during those times. A time setting and control for departure time. Finally, a control for precondition.

My utility has an EV charging program. They give me $7 a month discount for voluntarily not charging during peak times. I had to take a screenshot to show the setting for my charging control. Fortunately, they accepted the lame Tesla control page. I expect they don't really understand how it works, they just look at the time setting. I certainly can't claim that I can easily control the times my car charges. So I'm hooking up an external timer that I know how to program.

BTW, why can't you control this from the car?

 

[gnuarm]

I finally figured out what was wrong. The app is broken. The page showing the schedule can not be scrolled, with information hidden off the bottom of the screen. In particular, that is where the Off-Peak End Time is entered. To access this, I have to go into the phone settings and change the magnification on the entire phone to small.

All because they couldn't figure out they need to scroll a page with a variable length.

I had to change the master zoom on the phone to see these controls. I set the Off-Peak End Time for 3 pm, enabled Off-Peak Charging and let it start charging. Come 3 pm, it did not stop charging. It’s now 3:06 pm and it’s still charging.

I don’t see a way to make this work, ever.

I’ve stopped the charging manually. Do you think it will ever start up again on it’s own? It still needs to charge for 3 hours.

I think it only supports two modes. One is scheduled departure, where the start time is controlled by how much charge it needs to be done by the departure time (which is not always calculated accurately). This does not allow charging only at off-peak times, since you have no control over the charging start times, other than calculating the number of hours it needs to charge... a big hassle.

The other mode lets you schedule the charging start time, but exerts no control to stop charging other than when the battery has reached the charge limit setting. So again, this can't be used to avoid peak charging unless you calculate the charging rate, duration, etc. EVERY TIME YOU USE IT! Not much of a convenience.

So I no longer think I am simply not aware of how it works, because it doesn't work. Just like so many parts of a Tesla. I'm slotting the scheduled charging part of the Tesla app to the same shelf with the automatic headlight high beam control, the automatic wipers and the browser. My life is better if I just don't even try to use them.

 

[gnuarm]

I was reading the manual and found a section that clearly says the scheduled charging can not actually control the charging schedule as required for off-peak charging only.

First it's in the section

Using Scheduled Departure​

It claims this:

Off-Peak Charging delays charging and automatically starts charging in order to finish before your scheduled departure time while also ensuring to charge the Battery during off-peak hours to reduce energy costs.

Sounds like they are saying it will do what I want. Right? But after several notes, they say...

Note
Once charging has started and there is not enough time to complete charging during off-peak hours, charging continues until the charge limit is reached.

So they very clearly state that the charging will not be interrupted at the end of the off-peak charging time. The only thing that will stop charging is reaching the charge limit.

If this is what Tesla says, I'm pretty sure there's no reason to doubt them.

 

[noodlegawd]

Hi all, new M3 owner here. Sorry if this has been discussed ad nauseum already.

Is there an actual good reason that the charge scheduling function in the app doesn't allow you to simply schedule both the start time and stop time for charging? This can't be difficult to program, so what gives?

I want to schedule it to charge every day from midnight to 6am, which is when I have super-off-peak electricity rates. As far as I can tell, I have a two equally annoying and non-satisfactory choices. I can either:

• Set the start time at midnight, but then have to manually change the charge limit every day so it doesn't keep charging past 6am; or
• Set the departure time at 6am, but then it will start charging immediately (even if I set it to only charge off peak).

Am I missing something? Why is this so complicated?

 

[jjrandorin]

Is there an actual good reason that the charge scheduling function in the app doesn't allow you to simply schedule both the start time and stop time for charging? This can't be difficult to program, so what gives?

You are asking us to guess, as we dont know, but I would imagine its because there are so many different charging setups etc that if they did allow a start / stop time like that, they would probably end up with a ton of complaints about people not having enough charge to get to work / wherever they are going because it turned off.

For People who dont have enough charging speed to completely finish during that time, some would want it to finish charging, and some would want it to stop and charge "tomorrow, at peak rates".

Thats my guess anyway. It doesnt impact me at all, because I have my car(s) set to start charging at 2am and 3am, and they are always done by 6am. If your charging is fast enough to complete it in 6 hours, set your start time at midnight.

I dont trust teslas departure time thing anyway, so scheduling the start time is better to me (and has had zero issues, where departure time always has people wondering what its going to do, or why it didnt charge, etc).

 

[noodlegawd]

You are asking us to guess, as we dont know, but I would imagine its because there are so many different charging setups etc that if they did allow a start / stop time like that, they would probably end up with a ton of complaints about people not having enough charge to get to work / wherever they are going because it turned off.

For People who dont have enough charging speed to completely finish during that time, some would want it to finish charging, and some would want it to stop and charge "tomorrow, at peak rates".

Thats my guess anyway. It doesnt impact me at all, because I have my car(s) set to start charging at 2am and 3am, and they are always done by 6am. If your charging is fast enough to complete it in 6 hours, set your start time at midnight.

I dont trust teslas departure time thing anyway, so scheduling the start time is better to me (and has had zero issues, where departure time always has people wondering what its going to do, or why it didnt charge, etc).

My charging isn't fast enough. I'm just using a 110v outlet, and don't really need anything faster. I can get plenty of charge from it throughout the course of the week with just 6 hours of super off-peak charging per weeknight, and therefore I'm not terribly motivated to hire someone to install a 220/240 outlet. I typically drive about 40-50 miles per day, 2-3 days a week. I can recharge about 30 miles each night. That's enough to keep me above 60% until the weekend, when super-off-peak hours are extended and I can top off.

I simply want it to charge every day from midnight to 6 when the rates are lowest (it quadruples after 6 am). No more, no less. There's literally no way to automate this with the existing programming, which is pretty bizarre.

It's admittedly a minor annoyance, but a bit frustrating when something so simple and obvious is not available.

 

[STS-134]

Hi all, new M3 owner here. Sorry if this has been discussed ad nauseum already.

Is there an actual good reason that the charge scheduling function in the app doesn't allow you to simply schedule both the start time and stop time for charging? This can't be difficult to program, so what gives?

I want to schedule it to charge every day from midnight to 6am, which is when I have super-off-peak electricity rates. As far as I can tell, I have a two equally annoying and non-satisfactory choices. I can either:

• Set the start time at midnight, but then have to manually change the charge limit every day so it doesn't keep charging past 6am; or
• Set the departure time at 6am, but then it will start charging immediately (even if I set it to only charge off peak).

Am I missing something? Why is this so complicated?

You are asking us to guess, as we dont know, but I would imagine its because there are so many different charging setups etc that if they did allow a start / stop time like that, they would probably end up with a ton of complaints about people not having enough charge to get to work / wherever they are going because it turned off.

I actually find this very annoying, and I use scheduled departure, AND my departure time is set to 10am, AND I have off-peak rates from 5 pm, AND I have a 48A EVSE, so I can charge in less than 8 hours even if I come back with 0% and set it to charge to 100% (but I only have it set to 50%). Why? Because the scheduled departure feature requires you to tell the car when off-peak hours end, and I have that setting set to 5 pm which is when my off-peak rates end. A couple of issues:

- I can set the scheduled departure feature to operate Monday to Friday only, or 7 days a week. If I set it to operate Monday to Friday only, and I come back on Friday night and plug in, I've seen it actually treat Friday night as the beginning of the weekend, and start charging immediately. Not sure if they've fixed this behavior because I don't use the Monday to Friday only option (I prefer the car to actually wait before charging, so that the BMS can get a reading at the lower SoC level prior to charging back up).

- "Scheduled Departure" actually has two times per day that it tries to hit the charging limit. First is your scheduled departure time, and the second is the end of off-peak rates. If I go out during the day and come back very close to 5 pm, it will start charging as soon as I plug in. And it will keep on charging past 5 pm on peak rates (if it's a weekday). Very annoying. Actually, it does it on the weekends too, but I don't care, because weekends are off-peak 24 hours a day.

For People who dont have enough charging speed to completely finish during that time, some would want it to finish charging, and some would want it to stop and charge "tomorrow, at peak rates".

They just need two different charge limits. First, the lower "I want the charge level to be at least this" limit, where it will keep charging into peak rates or start charging during peak rates to meet that threshold, if necessary. And then a higher "It would be nice to get to this level but don't charge at peak rates to do it" threshold. For my usage, I'd set the limits to 0% and 50% respectively. If I come back and plug in with nearly 0% and I know that I have to go out again soon, then I'd simply do a manual override and tell it to start charging immediately.

 

[STS-134]

My charging isn't fast enough. I'm just using a 110v outlet, and don't really need anything faster.

You know that about 15-30% of the electricity that goes into your car never reaches the battery right? The computer consumes a constant 150-300W and runs the entire time it's charging. And at 120V, that overhead is over 15% of the total. Even using the slowest 240V outlet (a 6-15) would cut that overhead by 75%.

 

[M229984]

You know that about 15-30% of the electricity that goes into your car never reaches the battery right? The computer consumes a constant 150-300W and runs the entire time it's charging. And at 120V, that overhead is over 15% of the total. Even using the slowest 240V outlet (a 6-15) would cut that overhead by 75%.

What about sleeping the vehicle?

 

[Sophias_dad]

Hi all, new M3 owner here. Sorry if this has been discussed ad nauseum already.

Is there an actual good reason that the charge scheduling function in the app doesn't allow you to simply schedule both the start time and stop time for charging? This can't be difficult to program, so what gives?

I want to schedule it to charge every day from midnight to 6am, which is when I have super-off-peak electricity rates. As far as I can tell, I have a two equally annoying and non-satisfactory choices. I can either:

• Set the start time at midnight, but then have to manually change the charge limit every day so it doesn't keep charging past 6am; or
• Set the departure time at 6am, but then it will start charging immediately (even if I set it to only charge off peak).

Am I missing something? Why is this so complicated?

I agree it is a trivial exercise in programming. As a stopgap, you could get https://sg57productions.com/dashboardfortesla, which I believe does allow you to do just what you say, although you need an android phone to use it(and there's a one-time low purchase price). If you happen to have programming skills and a system that's running all the time, you could probably program it to do the same thing, since the API to the Tesla servers is apparently public knowledge.

 

[STS-134]

What about sleeping the vehicle?

That's definitely a problem. If the vehicle is constantly charging when it's not being driven, the BMS won't be able to get any readings. If it's never allowed to dwell at low SoC levels prior to charging, it won't be able to get any readings and the range estimate will get less and less accurate.

 

[noodlegawd]

You know that about 15-30% of the electricity that goes into your car never reaches the battery right? The computer consumes a constant 150-300W and runs the entire time it's charging. And at 120V, that overhead is over 15% of the total. Even using the slowest 240V outlet (a 6-15) would cut that overhead by 75%.

That may be the case, but I assume that the absolute amount of electricity that is "wasted" for that overhead is the same regardless of the voltage of my source, and a standard 110/120V outlet is adequate for my needs.

If and when I get solar and probably need a new panel anyway, I will surely get 240 outlets put in.

 

[STS-134]

That may be the case, but I assume that the absolute amount of electricity that is "wasted" for that overhead is the same regardless of the voltage of my source, and a standard 110/120V outlet is adequate for my needs.

If and when I get solar and probably need a new panel anyway, I will surely get 240 outlets put in.

The amount of electricity used to run the computers is the same in terms of the number of watts, yes. But charging at 120V/12A means you charge more than 8 times as long as you do at 240V/48A, which means you waste more than 8 times as much energy running the computers. Why more than 8 times, given that 240V/48A represents a power level of exactly 8 times? Well, consider what happens if we charge at 120V/1A compared to 120V/12A. Is it 12 times the amount of waste because the power is 12 times less? Nope. It's infinity, because 120V/1A won't even run the computer and you'll be charging forever (and by that I mean running the computer until your battery dies). Even if you only raise the power to 240V/12A, you cut the computer overhead in half, but you cut the charging time by more than half, because you get more than double the energy into the battery; none of that increase goes into running the computer and almost all of it goes to the battery.

120V charging is really, really bad. It should be avoided except in emergencies especially if you are paying for the electricity.

 

[noodlegawd]

The amount of electricity used to run the computers is the same in terms of the number of watts, yes. But charging at 120V/12A means you charge more than 8 times as long as you do at 240V/48A, which means you waste more than 8 times as much energy running the computers. Why more than 8 times, given that 240V/48A represents a power level of exactly 8 times? Well, consider what happens if we charge at 120V/1A compared to 120V/12A. Is it 12 times the amount of waste because the power is 12 times less? Nope. It's infinity, because 120V/1A won't even run the computer and you'll be charging forever (and by that I mean running the computer until your battery dies). Even if you only raise the power to 240V/12A, you cut the computer overhead in half, but you cut the charging time by more than half, because you get more than double the energy into the battery; none of that increase goes into running the computer and almost all of it goes to the battery.

120V charging is really, really bad. It should be avoided except in emergencies especially if you are paying for the electricity.

I'm confused. Is the computer only running at the level you're talking about when the car is charging?

 

[jjrandorin]

I'm confused. Is the computer only running at the level you're talking about when the car is charging?

its running at that level when its not sleeping, and the car does not sleep when its charging. The longer you take to charge, the longer you keep the car awake, the more relative energy you waste.

If you were running sentry mode the entire time instead, it would be the same thing.

 

[STS-134]

I'm confused. Is the computer only running at the level you're talking about when the car is charging?

Yep. The car does not sleep while charging, and the computer runs at the same power level it does when the car is on the entire time. The faster you charge, the faster it can shut down, sleep, and stop consuming that power.

 

[Viejo66]

The flip side of reduced charging time at higher amps is increased power loss to heat in the wires from your meter all the way to the tesla charger plug. At 48A of charging, one single volt of voltage drop is 48W. If you have 100ft of 6AWG wire from panel to your charger, plus that 20ft of charger cord that gets REALLY warm at 48A, that can be up to 6V drop, or around 288W lost to heat in the wires alone.

Ideally I'd prefer to schedule charging to start at a time of my choosing and then end at a time of my choosing, by automatically adjusting the amps to reach the SOC goal during that interval. So instead of charging 48A for two hours just prior to my selected departure time, charge at 12A for eight hours -- less energy lost to heat in the wires and lower peak power demand from the grid. If it can't reach target SOC by end time, should be a checkbox option for continue charging past endtime to reach goal SOC or postpone remainder of charging until next scheduled charge period.

Running a 300W computer flat out to monitor charging (if true) seems pretty wasteful. Surely the computer can sleep for minutes at a time between waking up periodically to sample the charging progress and adjust BMS parameters. I suspect this just hasn't percolated to the top of "what needs to be optimized next" and could certainly be improved.

Regardless, completely agree the current scheduled charging UI is very unintuitive, even for a retired software guy.