We’re in the process of switching to our new energy supplier (Octopus) Electric Vehicle (EV) Tariff. Of which the daytime rate of electric is around the same as other tariffs at 14p per unit, but for 4 hours a night this reduces down to 5p per unit. Roughly taking my yearly charging down from £200 to £70.
In hacking the charger control circuitry:
I then posted on SpeakEV about my postings and within discussion originally looked at connecting my own MCU between the car and evse’s Control Pilot Signal. This is a mixture of resistors to tell the charger if the car can charge or not and a PWM Signal back to tell the car the speed it can charge at.
But then someone said instead of intercepting the signal as I only wanted to control the timing to just connect and disconnect the control pilot. Even easier! Just a simple relay. Throughout discussion someone said the car might throw errors if the CP is just disconnected mid charging.
The solution to this was to also use the lock feature by locking the charger first then disconnecting the CP.
Ok, time to add a microcontroller and relays:
It was then time to implement it, I ordered a cheap 5V Dual Relay module off eBay as this was only low voltage being controlled.
Then the hardest part, what board to use? An arduino was too simple as I wanted it to have connectivity, after looking through my box of boards including Raspberry Pi, Onion Omega, Arduinos of lots of varieties and more I settled on the Particle Photon I have had in its box since backing it on Kickstarter.
The great thing is that it can be programmed via a Web IDE but also has IFTTT integration making it ideal.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.