Home charging your Tesla with Intelligent Octopus Go (UK)
Last updated 11-Jun-2024
Some Tesla owners are happy to simply plug their car into their home wall box and let the car start charging, others want to make use of cheaper overnight electricity which is available to many if certain conditions are met. Different electricity providers provide variations on a theme, some offer simply a fixed window overnight of cheap rate electricity, usually at the cost of a slightly higher daytime rates than flat rate tariffs. Others offer anytime charging of EVs at a lower rate but with certain stipulations. One of the most popular is a variation on these where you have an overnight period of cheap electricity for the whole household, plus any additional half hour slots that Octopus make available to help charge the car at the most appropriate time for the overall electricity grid, although you still control the target state of charge and by when you require it. It may sound complicated, but hopefully this guide will explain it is incredibly simple and can be incredibly economical.
Prerequisites
- You have to have a smart meter or be prepared to sign up to one.
- Have an EV that Octopus can communicate with directly, this includes Tesla, but also many other makes of EV such as BMW and Audi.
- Or, an EV charging wall box that Octopus can communicate with.
The basics of operation
Once set up, and we'll cover that later, you simply plug in. In the Octopus app you set the target state of charge and by what time you want this to be available, and Octopus will do the rest. If your target settings haven't changed, you don't even need to open the app, the setting you last set will be reused.
The car may start charging when you plug in, don't worry if it does, Octopus will typically detect the car charging and stop it within a minute or so.
Octopus will then create a schedule of charging which will have the car at the desired state of charge by the desired time, within the constraints of how fast the car can charge etc.
And that is it. And together with your car charging using cheap electricity, the whole house will benefit from cheap electricity between 23:30 and 5:30, so set you washing machine and dishwasher to operate between those hours too, and if you have a house battery or powerwall, charge that up too.
Signing and setting up
Before signing up, it is worth checking your car and or charger is compatible. Simply check via the Octopus website (using our referral) and enter your details and it will tell you.
Assuming there are no issues so far, you also need to have a smart meter. If you have one, then great, if you don't then you can either talk to your existing energy company and get them to install one, that way of there are problems you've not moved supplier needlessly, or move and let Octopus sort out installation. Smart meter roll out is sometimes problematic, many have no issues at all, others seem to struggle, and various aspects such as a poor mobile signal may cause a limitation. If you do not have a smart meter, maybe talk to neighbours and see if they've had issues.
Ok, so you're all ready to go, you effectively sign up the regular Octopus Energy provider, and as the process continues after a few days you'll be asked to register your car (or charger). Simply follow the steps, provide account details for your car, they will try and connect to the car and do a short test charge. We've found this took a few attempts, and we even moved the car slightly. but once the test charge is complete, you're done!.
And one last important point, if you use a referral code, either a friends or our octopus referral code, you'll get a £50 credit once you've signed up!
I don't have a smart meter or the car can't be connected to
If for whatever reason you can't or don't want a smart charger, or your car is impossible to connect to, then this won't be an option. There are alternative energy plans that might be suitable, although these tend to have shorter windows or be less attractive on the rate charged.
I have more than 1 EV
If you have more than 1 EV you need to manually schedule the second EV yourself, charging between 23:30 and 5:30, plus any other 30 mins slots that the primary car is scheduled to charge in (we'll explain more on that in a minute
The problem with 2 or more EVs is that many households can only support 1 car charging at a time at the full rate. If you have had DNO approval to charge 2 cars at the same time, then great, otherwise you'll need to schedule them to charge independently or use a pair of chargers that load balance, or charge the cars on alternate nights. A quick hack if you want to charge them both each night is to tell Octopus you want the car to be ready by say 3AM, the other car can be scheduled to charge from 3AM and will get 2.5 hours of charging, or about 18 kwh before the off-peak cutoff. For most, it's easier to simply alternate nights to avoid the clash.
Bonus slots and top tips
One of the factors that Octopus take into consideration when determining the schedule is the wholesale price of electricity in each 30 min slot. At certain times of the year, especially sunny, windy but warm days, there may be a surplus of energy and the wholesale price is low and sometimes even goes negative for some 30 min slots. Octopus may decide to schedule charging during these slots even if it is outside the normal cheap rate window, giving the whole house cheaper rate electricity. Don't worry though, they will only do that if the car will still be charged by your target time.
We've found, if you don't need the car first thing in the morning, setting the target time to 10:00 or 11:00 will give you the best opportunity of having one or more bonus slots. Another tactic is to set your target state of charge to say 70% or 80% and then when you wake up try increasing it to by 10%, for most cars this will require 2 extra 30 mins slots which if Octopus can, will schedule bonus slots within which the car will charge.
To know if you have bonus slots, simply check the app. These bonus slots can change so it is worth checking just before you plan to make the most of one.
In the example screenshot, and based on 23:30 to 05:30 is always at the cheap rate, the bonus slots are 07:00 to 07:30, and then again at 08:00 to 08:30
