Smart charging for your Tesla on hourly electricity prices

When you plug in at home and the battery is below your target, Amp makes a plan for that charge. From the car's own battery data it works out how much energy is missing, and from the charging power how long that takes, with a margin on top. Then it picks the cheapest price slots before your ready-by time and joins slots that lie close together, so the car charges in at most three windows.

A notification tells you when the car will charge, the average price per kWh and roughly how much that saves compared with charging straight away. Outside the windows Amp keeps the car from charging; when a window starts it starts charging, and when the window ends it stops. It never charges above the car's own charge limit.

Day-ahead prices for tomorrow are published around 13:00 CET, and Agile Octopus rates around 16:00 UK time. Plug in before then and the plan uses the hours already known; a plan that hasn't started yet is made again as soon as tomorrow's prices are in.

If a window is missed or charging runs slower than expected, Amp plans again from that moment, and if no cheap time is left before your ready-by time, it starts charging straight away. When there aren't enough priced hours before then, Amp doesn't hold the car back: it charges as usual, and the notification says so.

Charge Now — in the notification or on the Car tab — starts charging at once and ends the plan for this plug-in; Skip Plan just ends it. Start or stop charging yourself and Amp leaves that charge alone. If your energy supplier's app also does smart charging, turn one of them off so they don't fight over the car.

Since Amp 1.1, every home charge a plan scheduled shows what it saved: the same energy priced as if the car had charged straight away from the moment the plan was made — usually when you plugged in — minus what it really cost, both at the prices you pay. You see it on each charge in the Charging tab, Stats adds it up for the period you pick, Insights shows it month by month, and the monthly summary notification mentions it.

The comparison is always with charging straight away. If your car would otherwise have waited for its own scheduled charging time, your real saving is smaller. And when a charge ends up costing more than charging straight away would have, Amp shows that too.

Amp doesn't wake the car to check prices or watch the battery: it plans from what the car sends while it's awake anyway. The car is only woken when the plan has to start charging — at the start of a window, or to catch up.

Amp Pro, plus your home and hourly prices in Home & Prices: set your home location, turn on Dynamic energy contract, pick your price zone and enter your supplier's markup per kWh (supplier fee and energy tax, excluding VAT) and the VAT rate. On Agile Octopus, pick your region under United Kingdom · Agile Octopus instead; there's no markup or VAT to enter. Then switch on Smart charging in Settings → Automations and set Ready by and how far to charge, from 50 to 100%.

The all-in price per kWh is the market price plus your markup, plus VAT. On Agile Octopus it's the rate for each half hour, VAT included, without the daily standing charge. Every home charge on a dynamic contract is priced that way for the time it actually charged, so the Charging tab shows what it really cost, next to today's and tomorrow's prices.

Amp uses the day-ahead prices published on the ENTSO-E Transparency Platform for 30 price zones in 23 European countries: the Netherlands, Belgium, Germany and Luxembourg, France, Spain, Portugal, Austria, Switzerland, northern Italy, Denmark (DK1, DK2), Norway (NO1–NO5), Sweden (SE1–SE4), Finland, Poland, Czechia, Slovakia, Slovenia, Hungary, Estonia, Latvia, Lithuania and Ireland. If you pay in a currency other than the euro, prices are converted at the European Central Bank's reference rates.

In Great Britain, Amp uses the Agile Octopus unit rates that Octopus Energy publishes for each of its 14 regions, half hour by half hour. They're in pounds; if you pay in another currency, they're converted at the same reference rates. Northern Ireland is part of Ireland's price zone.

Other areas — including the rest of Italy and North America — aren't covered. There Amp prices charging at your fixed rates, and smart charging isn't available.

Amp is made by TIT and works with Tesla Model 3, Model Y and Tesla Cybertruck, and with Model S and Model X built in 2021 or later. It is an independent app, not affiliated with, endorsed or supported by Tesla, Inc.