Schedule Charging of your Tesla

Last updated 27-Sep-2023

Many Tesla owners are happy to simply plug their car into their home wall box and let the car start charging, and if you are happy doing that, then this guide probably is not for you, other than maybe the comments on Preconditioning.

However, if you want to schedule the charging to make use of cheap rate electricity or maximise solar energy you capture, then this guide will explain the 3 different native options Tesla provide.

This guide covers

Scheduled start time using the in car scheduler
Scheduled end time using the in car scheduler
Wall box scheduled window
Shortcuts and iOS automation

We also have specific guides on General Tesla charging and Tesla supercharging

In Car Scheduler

There are essentially 2 different charge scheduling options in the car, and these can not be combined. There is an additional precondition option which uses the same menus and can cause some confusion, which we will also explain. All these options can be set via either the car or the app.

The default for the cars will be to try and start charging as soon as you plug the car in. The car will then continue to charge until the target state of charge is reached, and then stop. It may top up the charge level perodically if the car is left for some time, but essentially the car just wants to get you to the desired charge level and keep the car there.

It's worth clarifying at this point that a car will only charge if every part of the chain is happy to charge. Technically the car will only charge if both the car and the wall charger allow charging at that point in time.

Schedule start charging

This is the easiest option to understand. You simply set a time in the car when you want the charging to start. The car will do nothing until then, and just start charging at that point in time

It's worth clarifying at this point that a car will only charge if every part of the chain is happy to charge. Technically the car will try and start charging at the requested time, if the car wall charger has it's own schedule that says something different, the car might not actually succeed in charging.

Schedule end of charging (off peak)

This is the hardest option to understand. This option effectively works backwards. You tell the car two pieces of information, when you want the car, and when off-peak charging finishes.

When you plug the car in, the first thing the car does is calculates how long it will need to charge for to reach the required state of charge from the current level. Lets say this is 3 hours and 40 minutes.

The car then works out which is sooner, the time off peak finishes or when you need the car. From the earlier of those two times it subtracts the time it needs to charge to work out when it needs to start charging. So say offpeak finishes at 6AM, you want the car at 7AM, the car determines it needs to finish charging by the earlier of the two, ie 6AM, it needs to charge for 3 hours 40mins, it therefore needs to start charging at 2:20 AM. In practice we think the car also builds in a little slack and would probably start charging around 2AM.

Whenever you adjust a parameter, the car recalculates. As an example, if you increase the target state of charge to 100%, and this means the car would need to charge for an extra 2 hours, it would move forward the calculated start time. Similarily, if you decided you needed the car at 5AM, even though the off peak rate would last until 6AM, the car will use 5AM as the reference time to work backwards from. The car is trying to ensure the car is fully charged when you come to leave.

What you can't do is set a start and end time to charge because you're more interested in the low rate tariff than you are achieving a certain state of charge, however this can be done a different way.

In the image shown, both Preconditioning and off peak charging are enabled.

Schedule preconditioning

This has actually has nothing really to do with charging, other than the time set for when you wish to depart will also be used if you elect off-peak charging. If the preconditioning option is ticked, and a scheduled departure time entered, the car will heat up the cabin for when you depart. It may draw the energy required from a wall charger if one is plugged in to perform the task, but the amount of energy is typically fairly small.

It's therefore possible to set a scheduled start time for the charging, and a scheduled departure time for preconditioning, but you can not set a scheduled start time, and a scheduled departure time for off peak charging.

Wall box Scheduler

The Tesla wall box can be added to the app and some basic settings can be controlled when it is. The one relevant here is to set a schedule, or probably more accurate, the setting of a window when the charger will allow charging.

You simply set the start time and the end time, there is also an option to randomise the start but this is purely to help energy supplies cope with sudden demands all at the same time.

There are a couple of reasons why this might be a good idea. The first is if you have an off peak window for cheaper electricity and are less bothered about the day to day state of charge. If the cheap rate is from midnight to 6am, you could charge every night for those hours and if the car has not quite reached your selected state of charge, you are not bothered as you still have plenty for the day ahead, and this will be most peoples situation except for when they have a long trip the following day.

Another scenario is if you want to prevent the unauthorised use of the charge port. The Tesla wall charger does have other options such as limiting hte use to only chargers or even specific vins, but you may wish for the use to be more widely used, say outside an office during hte day by visitors, but not over night by people who are not visitors to your business.

Shortcut and API control

The final way is to make use of the Tesla app and it's ability to allow iOS shortcuts to be created that perform certain tasks. Third party solutions make use of similar capabilities but they all, including our own, require you to share you Tesla access token which could give rise to security issues if it fell into the wrong hands. The approach we cover here does not have this issue.

We've covered making these controls elsewhere so we will only summerise the steps required here. They are:

Create a new iOS shortcut and call it something intuitive such as "start charging"
Add an action from an App, select the Tesla app from the list, and then find stop/start charge
Fill in the boxes by selecting them, you will need to select the action (stop or start) and which car on your account.
You will need to create a start and a stop charging shortcut, and if you have more than once car, one for each car, the naming convention of your shortcuts will also need to make it more obvious to which car each refers to.
Once you have created the shortcut, you can optionally allow it to be added to an Apple watch if you wish to control it that way, or you can create a custom automation from within the shortcuts app.
The custom automation can be triggered by a time, or one of a number of other events. You may also be able to link the control to solar production so the car charges when you are exporting to the grid.
The advantages of this approach is you have easy control over the charging and overriding it. For instance you can simply trigger the charging to start earlier if you want by running the start charging shortcut. The downsides are largely linked to the app performance and waking the car up when needed to start or stop charging.

The video below walks you through all these options: