Ember EV - Charge Smarter
Find the cheapest Octopus Agile slot to charge your Tesla
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Myles Carey

Ember EV - Charge Smarter - Find the cheapest Octopus Agile slot to charge your Tesla

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Octopus Agile prices change every 30 minutes. Some slots cost 3p/kWh, others hit 50p. The difference could be hundreds of pounds a year - but who's checking wholesale prices at 2am? Ember watches for you. Every day it scans all 48 half-hourly slots, finds the cheapest window for your battery level, and tells you when to plug in. It connects to your Tesla, reads your charge state, and calculates the actual energy needed. Built for one user (me), designed for anyone on Agile with a Tesla.

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Myles Carey
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Hey PH! I'm Myles. I built Ember because I kept missing cheap electricity. I was on a fixed EV tariff and paying way more than I needed to. I kept seeing people on Octopus Agile talk about charging their Tesla's for 3-6p/kWh when wholesale demand drops. I was paying £0.15p per kwh on a overnight tariff. So I switched. The thing is, agile prices change every half hour, and the cheapest window is different every day. Sometimes it's midday, sometimes in the morning. I wanted something to figure it out for me. So I built Ember. Every day it pulls the next day's 48 price slots, checks my Tesla's battery level, and finds the cheapest block of time to get me to my target charge. Then it pings me and tells me when to plug in. A few things I'm proud of: ✨ Battery-aware: it calculates the actual kWh you need, not a fixed schedule ⚡ Handles negative prices (yes, sometimes they literally pay you to use electricity) 🔍 No "overnight charging" assumption. The cheapest window could be any time of day Right now it runs in 2 modes: advisory mode: finds the window, sends you a notification, you plug in. Automated scheduling mode: Where Ember sets the charge on your car directly. It is already running on my own car and working great. The first 10 beta users get automated scheduling free, forever. Energy prices seem to always be heading up. If you're on Agile or thinking about switching, Ember is built to make sure you're never overpaying to charge. Every penny counts right now. Anyone else here on a time-of-use tariff? How are you handling this today?