Tesla Broke Off-Peak Charging

[Bill Flav]

With the latest software, if you want your car to charge only when electricity rates are off-peak, you can't (at least not easily). If you choose Scheduled Charging, you can set a time when the car will start charging and you can set this to coincide with the start of off-peak rates. But the car will charge until it reaches the % battery level that has been set. If it does not achieve this by the end of off-peak rates, it will continue to charge at peak rates.

Some people will want this behaviour and some will not--I do not. Unless I have a long journey the next day, I normally want to restrict charging to off-peak periods only. The only way to do this is to calculate what battery % will be achieved by the end of the off-peak period and set that as a charge limit. And you will have to do this every time you charge! Many people will not have a clue how to do this and, anyway, what a faff!

There could be another way to achieve this. Choose Scheduled Departure and Off-peak charging but set the Departure time to the time when off-peak rates end--at 04:30 for instance. The problem here is, if you do not unplug the car at 04:30, it will continue charging until it reaches the preset battery charge %. No, I'm not getting out to bed at 04:30 to unplug my car!

This gap is easily fixed. There is already the ability to set off-peak rates. We just need the option to "Charge during off-peak hours only at this location--Yes/No".

I've been a Tesla owner since 2015 but in that time my wife has owned a Renault Zoe, a Nissan Leaf and a Hyundai Kona. All of these "lesser" vehicles allow off-peak charging to be easily achieved. Until recently, it was easy to achieve in my Model S but a software update some months ago changed everything and took this highly desirable facility away.

Have I missed something or am I right?

 

[OxBrew]

I'm still on v10, and have not updated the app since December. Off peak charging seems to try to stop at the end of the set period, but is seemingly incompatible with any other feature, like preconditioning. Honestly, the Schedule function is a hot mess. It's nearly incomprehensible. The tragedy is designing a scheduled start/stop function is almost trivially easy, if someone just applies some clear thinking to it.

Add this to the reasons I'm not updating to v11.

 

[serendipitous]

With the latest software, if you want your car to charge only when electricity rates are off-peak, you can't (at least not easily). If you choose Scheduled Charging, you can set a time when the car will start charging and you can set this to coincide with the start of off-peak rates. But the car will charge until it reaches the % battery level that has been set. If it does not achieve this by the end of off-peak rates, it will continue to charge at peak rates.

Some people will want this behaviour and some will not--I do not. Unless I have a long journey the next day, I normally want to restrict charging to off-peak periods only. The only way to do this is to calculate what battery % will be achieved by the end of the off-peak period and set that as a charge limit. And you will have to do this every time you charge! Many people will not have a clue how to do this and, anyway, what a faff!

There could be another way to achieve this. Choose Scheduled Departure and Off-peak charging but set the Departure time to the time when off-peak rates end--at 04:30 for instance. The problem here is, if you do not unplug the car at 04:30, it will continue charging until it reaches the preset battery charge %. No, I'm not getting out to bed at 04:30 to unplug my car!

This gap is easily fixed. There is already the ability to set off-peak rates. We just need the option to "Charge during off-peak hours only at this location--Yes/No".

I've been a Tesla owner since 2015 but in that time my wife has owned a Renault Zoe, a Nissan Leaf and a Hyundai Kona. All of these "lesser" vehicles allow off-peak charging to be easily achieved. Until recently, it was easy to achieve in my Model S but a software update some months ago changed everything and took this highly desirable facility away.

Have I missed something or am I right?

They didn't break anything - it's always worked this way. For a while you could only set a start time, later they added the ability to set an end time (but still never both), and even more recently they've added the ability to set a departure time separate from an off-peak end time.

I guess being spoiled by not having any discount for off-peak, I'm baffled why people want this functionality. You're driving a car. The absolute WORST possible experience is to tell the car you want to have 90% charge and find out that because of your settings that the car decided to save you $4 by stopping at 42% because you only gave it a few hours to charge when it needed longer. The charge limit should absolutely take precedence over all other matters in my opinion. If you're that worried about saving money rather than your car's range, then just change slider - there's no reason to charge past the amount you need the next day anyway! It'll be better for your battery in the long run to just leave at charging to 60% every day, comfortable in the knowledge that your car will never need to extend before or after your off-peak rate period.....

 

[GtiMart]

Seems like using scheduled start at the beginning of your low rate period is best. Then you can easily calculate the time it will take and adjust the target SOC accordingly. On my 2020 model 3 LR AWD I know that charging on my 11kW (240V 48A) home charger yields ~13% SOC per hour. After charging a few times you'll know how much you gain in an hour.
I also believe that target SOC is a very important value, that's why I suggest adjusting it for your use case.

 

[sleepydoc]

Seems like using scheduled start at the beginning of your low rate period is best. Then you can easily calculate the time it will take and adjust the target SOC accordingly. On my 2020 model 3 LR AWD I know that charging on my 11kW (240V 48A) home charger yields ~13% SOC per hour. After charging a few times you'll know how much you gain in an hour.
I also believe that target SOC is a very important value, that's why I suggest adjusting it for your use case.

Yeah, that’s probably the best way but still kind of a poor hack. There’s enough people who have off peak charging rates that they should add a charging window option.

 

[OxBrew]

Yeah, that’s probably the best way but still kind of a poor hack. There’s enough people who have off peak charging rates that they should add a charging window option.

Yeah, and then allow us to set a priority flag, either on the off peak window or the charge %.

Days I'm bopping around town, I just take what I get off peak, I don't really care, days I need more charge for longer trips, I can choose to prioritize the charge % and just blow through the end of the window, pay the 3 bucks more or whatever.

Plus add a departure time to all of it, either way. That's what's weird to me.

I expected, prior to buying the car, that I would be able to set all the following:

Departure time
Target charge %
Off peak hours

And Tesla would add it all up and do it's thing, I don't have to calculate or micro manage anything.

Easy logic:

If target % can be met in off peak charging window, do that, then stop, then precondition if needed (based on outside temps).

If target % needs to extend beyond end of off peak window, but can still be met before departure, start at start of off peak, and continue to target %, same about pre conditioning.

If still more time is needed to hit target %, start far enough before off peak window to still hit target % by departure time, and condition as needed.

Code it, done. Hell, a good coder could do it in an hour. I know just the guy.

 

[ItsNotAboutTheMoney]

As noted, it doesn't even match the Kona's basic off-peak window, and it doesn't come close to the Volt (and Bolt).

 

[GtiMart]

They could indeed do better. In the meantime, since there's an API that's been reverse-engineered, one should be able to program pretty much what they want using it. I believe TeslaFi has programmability, and other such apps probably can too.

 

[serendipitous]

Easy logic:

If target % can be met in off peak charging window, do that, then stop, then precondition if needed (based on outside temps).

If target % needs to extend beyond end of off peak window, but can still be met before departure, start at start of off peak, and continue to target %, same about pre conditioning.

If still more time is needed to hit target %, start far enough before off peak window to still hit target % by departure time, and condition as needed.

Code it, done. Hell, a good coder could do it in an hour. I know just the guy.

It literally does exactly what you asked for today, using Scheduled Departure and setting an Off-peak end time. It doesn't need to know or care about the start of your off-peak to meet the objectives you laid out, and that's why it doesn't. It will start more-or-less as late as it can to hit your % by the earlier of your departure time or off-peak end time. If that means it has to start before your off-peak starts, it will, because that's the right thing to do. Separately it will pre-condition before your departure time.

....

 

[OxBrew]

It literally does exactly what you asked for today, using Scheduled Departure and setting an Off-peak end time. It doesn't need to know or care about the start of your off-peak to meet the objectives you laid out, and that's why it doesn't. It will start more-or-less as late as it can to hit your % by the earlier of your departure time or off-peak end time. If that means it has to start before your off-peak starts, it will, because that's the right thing to do. Separately it will pre-condition before your departure time.

....

OK, fair point, but it does not seem to do this. If it does, it's not showing me that. It always starts charging immediately, regardless of off peak setting. No matter what I set it to, I can't get it to delay charging start. It's pretty confusing as it's currently set up.

I'll play with it this evening, see if it's any better than last time I tried it.

(edit: corrected my comment about delay charging start)

 

[sleepydoc]

It literally does exactly what you asked for today, using Scheduled Departure and setting an Off-peak end time. It doesn't need to know or care about the start of your off-peak to meet the objectives you laid out, and that's why it doesn't. It will start more-or-less as late as it can to hit your % by the earlier of your departure time or off-peak end time. If that means it has to start before your off-peak starts, it will, because that's the right thing to do. Separately it will pre-condition before your departure time.

....

The problem arises when the expected charging duration is long enough that the car needs to start charging too soon. Many people have lower power (20-30A) charging circuits that take longer to charge.

 

[serendipitous]

The problem arises when the expected charging duration is long enough that the car needs to start charging too soon. Many people have lower power (20-30A) charging circuits that take longer to charge.

Why is that a problem? Again, the car gives you two modes, both of which prioritize the car reaching the level of charge you want, which is 100% the correct behavior in my opinion. You can tell it when to start, to align with the start of your off-peak period. It will take as long as it needs to in order to reach your target charge. If you don't actually need 80% charge, why would you charge it to that amount when you're home overnight? You're just wasting electricity and stressing your battery for no reason (LFP batteries excluded). Or you can tell it when you're leaving, and it will make sure it's charged and warm by then, OR will even start charging earlier if needed, if you also tell it when your off-peak ends so it finishes before then to save money. Again, you told it "I want to leave at 6:30 with 80% charge" - there is no world in which the car should assume you'd rather save money by having less charge. Adding more knobs so satisfy some weird desire to "charge up to this amount if you can during this specific window" is just confusing and adds unecessary battery stress while guaranteeing people are going to accidentally wake up one morning stranded because their car doesn't have the level of charge they intended.

 

[sleepydoc]

Why is that a problem? Again, the car gives you two modes, both of which prioritize the car reaching the level of charge you want, which is 100% the correct behavior in my opinion. You can tell it when to start, to align with the start of your off-peak period. It will take as long as it needs to in order to reach your target charge. If you don't actually need 80% charge, why would you charge it to that amount when you're home overnight? You're just wasting electricity and stressing your battery for no reason (LFP batteries excluded). Or you can tell it when you're leaving, and it will make sure it's charged and warm by then, OR will even start charging earlier if needed, if you also tell it when your off-peak ends so it finishes before then to save money. Again, you told it "I want to leave at 6:30 with 80% charge" - there is no world in which the car should assume you'd rather save money by having less charge. Adding more knobs so satisfy some weird desire to "charge up to this amount if you can during this specific window" is just confusing and adds unecessary battery stress while guaranteeing people are going to accidentally wake up one morning stranded because their car doesn't have the level of charge they intended.

No, You can tell it when to start or you can tell it when to end but not both. If you tell it when to end it starts when it wants to without regard to any off peak times. There are plenty of worlds where people want to charge up as much as possible but don't want to go outside of their off peak window - just look at this thread. Like @OxBrew said, the logic is simple, it's just a matter of Tesla bothering to implement it.

 

[OxBrew]

I did look at how mine's working again. I'm on a mid December app version (don't want to get ahead of my v10 UI) so this might be a bit outdated, but still really recent in the larger scheme of things.

If I set %, departure time, and off peak end time, I do get a delayed start as expected, which appears about right (last night I only wanted to add 8%, 67 to 75%).

Just a departure time plus preconditioning starts charging immediately.

Just a start time works as expected.

So for me, just the Departure time is wonky.

Just trying to clarify what was happening before.

I'd still like to be able to set the start of the off peak window, even if it's just making me happy and shuts me up.

 

[serendipitous]

No, You can tell it when to start or you can tell it when to end but not both. If you tell it when to end it starts when it wants to without regard to any off peak times. There are plenty of worlds where people want to charge up as much as possible but don't want to go outside of their off peak window - just look at this thread. Like @OxBrew said, the logic is simple, it's just a matter of Tesla bothering to implement it.

Again there are three settings. You people are all asking for a mode that allows them to contradict each other, and even more confusing, you're asking that the car prioritize the worst possible choice - to let you set things in a contradictory way and then end up with less charge than you told it you wanted.

I don't have a horse in this race but I think this is a stupid feature and I still don't get why so many people think they want it. At best you might ask for the ability to set an off-peak range independent of the charging logic, and have the app alert you if it's going to charge outside that range.

 

[sleepydoc]

Again there are three settings. You people are all asking for a mode that allows them to contradict each other, and even more confusing, you're asking that the car prioritize the worst possible choice - to let you set things in a contradictory way and then end up with less charge than you told it you wanted.

I don't have a horse in this race but I think this is a stupid feature and I still don't get why so many people think they want it. At best you might ask for the ability to set an off-peak range independent of the charging logic, and have the app alert you if it's going to charge outside that range.

It’s really not that tough - set a goal charge, a departure time and a earliest acceptable start time (e.g. 80% by 6AM starting after 11 pm.) If there’s not enough time the car gives a warning that lets you override, otherwise it charges as much as it can during that time. Not sure what’s so tough about that.

 

[3sr+buyer]

It would be so much easier to understand if the charge scheduling had this interface:

• You can set when peak hours start and end (or download them like the app can to estimate your charging costs).
• For scheduled start or immediate charging, options to:
  • Stop charging during peak hours (resuming in off-peak hours).
  • Continue charging through peak hours.
• For scheduled end charging, options to:
  • Stop charging during peak hours (resuming in off-peak hours), even if charging cannot be completed by the end time.
  • Minimize charging during peak hours while ensuring completion by the end time if possible.
  • Disregard peak hours when scheduling charging.

 

[zikronix]

I just replaced my charge point charger with the tesla one and was flabbergasted that this was not a basic feature with out being convoluted Both the ChargePoint and Juicebox do this perfectly fine

 

[AlexHung]

I use OptiWatt to manage my charging for this very reason.

 

[sleepydoc]

I use OptiWatt to manage my charging for this very reason.

That’s probably the best solution. It’s be nice if Tesla updated their app and charging routines to add a bit more flexibility, though.