Prioritize EV Charging With Solar Excess: A Smart Guide

Aug 3, 2025 by ADMIN 56 views

Smart EV Charging Prioritization with Solar Excess for Multiple Vehicles

Hey guys! Let's dive into an exciting topic about making the most of your solar power and electric vehicle (EV) charging setup. If you're like many EV owners with solar panels, you're probably thinking about how to prioritize charging your vehicles using excess solar energy. This article will explore how you can set up a system to ensure your most frequently used EV gets charged first, making your renewable energy usage even more efficient.

Understanding the Challenge

The main challenge we're tackling here is how to prioritize EV charging when you have multiple vehicles and limited solar excess. Imagine you have two EVs: one driven daily and another used less frequently. You want to ensure the daily driver gets charged first using your solar power, and only if there's excess, the second vehicle gets its share. This requires a smart system that can manage the charging process based on priority.

The Problem with Unsupported Wallchargers

Many EV owners face the issue of having unsupported wallchargers, meaning they can't directly control the charging process through a smart system. In this case, the user has Newmotion wallchargers, which, unfortunately, can't be controlled directly. This limitation adds a layer of complexity but don't worry, we'll figure out a workaround!

Leveraging Tesla's and ESPHome-Tesla-BLE

Fortunately, there's a silver lining! Tesla vehicles can be controlled via ESPHome-Tesla-BLE, a fantastic solution that allows you to manage your Tesla's charging behavior. This control is crucial for implementing a prioritization system. By integrating ESPHome-Tesla-BLE, you gain the ability to start, stop, and adjust the charging current of your Tesla, which is the key to prioritizing charging.

The Proposed Solution: Prioritizing EV Charging

The core idea is simple: set a priority for each vehicle and allocate solar excess accordingly. Here’s a breakdown of how this can work:

Setting Vehicle Priorities

First, you need to define the priority of each vehicle. In our example, the wife’s Tesla is used daily, making it the top priority. The other Tesla, used less frequently, gets a lower priority. This prioritization is the foundation of our smart charging system. Clearly defining which vehicle needs to be charged first ensures that your daily driving needs are always met.

How to Set Up the Prioritization

To make this work, we need a system that can monitor solar excess and control the charging of the Teslas. Here’s a step-by-step approach:

Monitor Solar Excess: You'll need a system that can track how much excess solar energy you're producing. This typically involves a solar monitoring system that provides real-time data on your solar production and home energy consumption. Many smart inverters and energy management systems offer this functionality.
Control Teslas via ESPHome-Tesla-BLE: Integrate ESPHome-Tesla-BLE with your Tesla vehicles. This setup allows you to send commands to your Teslas to start or stop charging and adjust the charging current. The beauty of ESPHome is its flexibility and integration capabilities with other smart home platforms.
Central Control System: Use a central control system to make decisions based on solar excess and vehicle priority. This could be a home automation platform like Home Assistant, which is highly recommended for its flexibility and extensive integrations. Home Assistant can read data from your solar monitoring system and send commands to your Teslas via ESPHome-Tesla-BLE.

Implementing the Logic

Here’s the logic you’ll implement in your central control system:

Check for Available Vehicles: Determine which vehicles are plugged in and ready to charge. This is a crucial first step to ensure that you're only allocating energy to vehicles that can actually use it.
Allocate to Priority Vehicle: If the high-priority vehicle (Car #1, the wife's Tesla) is available and there's solar excess, allocate all available excess energy to it. This ensures that the vehicle used daily gets the charge it needs.
Distribute Excess to Lower Priority: If Car #1 is fully charged or not available, and there’s still excess solar energy, distribute it to the lower-priority vehicle (Car #2). This maximizes the use of your solar energy without compromising the charging needs of your primary vehicle.

Example Scenario

Let’s walk through a scenario. Imagine it's a sunny day, and you have 5kW of excess solar power. Car #1 (wife's Tesla) is plugged in and needs charging, while Car #2 is also plugged in but doesn't need as much charge.

The system detects 5kW of excess solar power.
It identifies that Car #1 is the priority vehicle and is available for charging.
All 5kW of excess power is directed to Car #1.
Once Car #1 is fully charged, any remaining excess power will be directed to Car #2.

Hardware and Software Components

To make this solution a reality, you'll need a few key components:

1. Solar Monitoring System

A reliable solar monitoring system is essential. This system tracks your solar power production and home energy consumption, providing real-time data to your central control system. Many solar inverters come with built-in monitoring capabilities, or you can use a dedicated energy monitoring system like Sense or Emporia Vue. These systems provide APIs that allow Home Assistant to access the data, making integration seamless.

2. ESPHome-Tesla-BLE

ESPHome-Tesla-BLE is the bridge between your control system and your Tesla vehicles. It allows you to send commands to your Teslas over Bluetooth Low Energy (BLE). You'll need an ESP32 development board, which is flashed with the ESPHome firmware and configured to communicate with your Teslas. This setup gives you granular control over your Tesla's charging behavior.

3. Home Automation Platform (Home Assistant)

Home Assistant is the brains of the operation. It's a powerful open-source home automation platform that can integrate all your devices and services. Home Assistant can read data from your solar monitoring system, communicate with your Teslas via ESPHome-Tesla-BLE, and implement the charging prioritization logic. Its flexibility and extensive integration capabilities make it an ideal choice for this project.

4. Smart Plugs (Optional)

If you have non-Tesla EVs or want an additional layer of control, consider using smart plugs with energy monitoring capabilities. These plugs can be used to switch charging on or off and provide data on energy consumption, allowing you to integrate non-Tesla EVs into your prioritization system. Brands like Tasmota and Shelly offer excellent options that integrate well with Home Assistant.

Setting Up Home Assistant

Home Assistant is the heart of our smart charging system. Here’s a high-level overview of how to set it up:

1. Install Home Assistant

There are several ways to install Home Assistant, but the most common is using Home Assistant OS on a Raspberry Pi or a dedicated Home Assistant Blue device. Follow the official Home Assistant installation guide for detailed instructions.

2. Integrate Solar Monitoring System

Integrate your solar monitoring system with Home Assistant. This usually involves installing a specific integration or custom component that can communicate with your solar inverter or energy monitoring system. Home Assistant has integrations for many popular solar systems, making this step relatively straightforward.

3. Set Up ESPHome Integration

Integrate ESPHome with Home Assistant. This involves installing the ESPHome add-on in Home Assistant and configuring it to communicate with your ESP32 devices. Once set up, you can manage your ESPHome devices directly from Home Assistant.

4. Configure ESPHome-Tesla-BLE

Configure ESPHome-Tesla-BLE on your ESP32 devices. This involves flashing the ESP32 with the ESPHome firmware and configuring it to communicate with your Tesla vehicles. The ESPHome-Tesla-BLE documentation provides detailed instructions on this process.

5. Create Automations

Create automations in Home Assistant to implement the charging prioritization logic. This involves setting up triggers based on solar excess and conditions based on vehicle availability and priority. Home Assistant’s automation editor allows you to create complex automations with a user-friendly interface.

Writing the Automation Logic

Let's get into the nitty-gritty of writing the automation logic in Home Assistant. We’ll use YAML, the language used for configuring Home Assistant automations.

Example Automation

Here’s an example of an automation that prioritizes charging Car #1 (wife's Tesla) when there’s excess solar power:

automation:
  - alias: "Prioritize Car #1 Charging with Solar Excess"
    trigger:
      - platform: numeric_state
        entity_id: sensor.solar_excess_power # Replace with your solar excess sensor
        above: 1000 # Trigger when excess power is above 1000W
    condition:
      - condition: state
        entity_id: binary_sensor.car_1_plugged_in # Replace with your car plugged-in sensor
        state: "on"
    action:
      - service: switch.turn_on
        entity_id: switch.car_1_charger # Replace with your car charger switch (ESPHome-Tesla-BLE)
      - service: notify.persistent_notification
        data:
          title: "EV Charging"
          message: "Starting Car #1 charging with solar excess."

This automation triggers when the sensor.solar_excess_power is above 1000W. It checks if binary_sensor.car_1_plugged_in is on, indicating that Car #1 is plugged in. If both conditions are met, it turns on the charger for Car #1 (switch.car_1_charger) and sends a notification.

Distributing Excess to Lower Priority

Here’s an example of an automation that distributes excess power to Car #2 if Car #1 is fully charged or not available:

automation:
  - alias: "Distribute Excess to Car #2"
    trigger:
      - platform: numeric_state
        entity_id: sensor.solar_excess_power # Replace with your solar excess sensor
        above: 1000 # Trigger when excess power is above 1000W
    condition:
      - condition: or
        conditions:
          - condition: state
            entity_id: binary_sensor.car_1_plugged_in # Replace with your car plugged-in sensor
            state: "off"
          - condition: state
            entity_id: sensor.car_1_charging_state # Replace with your car charging state sensor
            state: "charged"
      - condition: state
        entity_id: binary_sensor.car_2_plugged_in # Replace with your car plugged-in sensor
        state: "on"
    action:
      - service: switch.turn_on
        entity_id: switch.car_2_charger # Replace with your car charger switch (ESPHome-Tesla-BLE)
      - service: notify.persistent_notification
        data:
          title: "EV Charging"
          message: "Starting Car #2 charging with solar excess."

This automation triggers when there’s excess solar power. It checks if Car #1 is either not plugged in or fully charged. If Car #2 is plugged in, it turns on the charger for Car #2 and sends a notification.

Benefits of Prioritizing EV Charging

1. Maximizing Solar Energy Use

By prioritizing EV charging with solar excess, you’re making the most of your renewable energy investment. You’re using free, clean energy to power your vehicles, reducing your reliance on the grid and lowering your electricity bills. This is a huge win for both your wallet and the environment.

2. Reducing Electricity Costs

Charging your EVs with solar power significantly reduces your electricity costs. Grid electricity can be expensive, especially during peak hours. By using solar excess, you’re essentially getting free fuel for your vehicles, which can lead to substantial savings over time.

3. Supporting Sustainable Living

Prioritizing EV charging with solar excess is a significant step towards sustainable living. You’re reducing your carbon footprint by using renewable energy and contributing to a cleaner environment. Every kilowatt-hour of solar energy you use is a kilowatt-hour less of fossil fuel energy being consumed.

4. Extending Battery Life

Consistent, slow charging is better for EV batteries than fast charging. By using solar excess, you’re often charging at a slower rate, which can help extend the life of your EV batteries. This is an added benefit that can save you money in the long run.

Potential Challenges and Solutions

1. Unsupported Wallchargers

Challenge: The primary challenge is dealing with unsupported wallchargers. Since you can’t directly control them, you’ll need to rely on controlling the charging via the Teslas themselves.

Solution: Use ESPHome-Tesla-BLE to manage the charging process. This allows you to start, stop, and adjust the charging current of your Teslas, effectively working around the limitations of your wallchargers.

2. Fluctuating Solar Production

Challenge: Solar power production fluctuates depending on weather conditions. This can make it challenging to maintain a consistent charging schedule.

Solution: Implement a buffer or hysteresis in your automation logic. For example, instead of triggering charging at exactly 1000W of excess power, you might set it to trigger at 1200W and stop at 800W. This prevents the system from constantly starting and stopping charging due to minor fluctuations.

3. Complex Automation Logic

Challenge: Writing complex automation logic can be daunting, especially if you’re new to Home Assistant or YAML.

Solution: Break the problem down into smaller, manageable parts. Start with basic automations and gradually add complexity. There are also plenty of resources and communities online that can help you with specific issues. Don't hesitate to ask for help!

Conclusion

Prioritizing EV charging with solar excess is a smart and sustainable way to power your vehicles. By leveraging tools like ESPHome-Tesla-BLE and Home Assistant, you can create a system that ensures your most frequently used EV gets charged first, maximizing your solar energy usage and reducing your electricity costs. It might seem a bit complex at first, but with a step-by-step approach and a little bit of tinkering, you can create a highly efficient and eco-friendly charging solution. So, go ahead, give it a try, and enjoy the benefits of smart, solar-powered EV charging!

I hope this comprehensive guide helps you set up your smart EV charging prioritization system. Happy charging, and let’s make the most of that solar energy, guys!