Optimize Your Battery Charging with Time-of-Use Tariffs

If you have a home battery and a time-of-use tariff like Octopus Agile or Intelligent Go, you're sitting on a goldmine of potential savings. The key is charging your battery when electricity is cheapest and using that stored energy during peak hours.

Understanding Time-of-Use Tariffs

Time-of-use (ToU) tariffs charge different rates depending on when you use electricity:

Setting Up Automated Charging

Step 1: Connect Your Tariff

First, ensure your Octopus Energy account is connected in OhmMy. Navigate to Settings > Integrations > Octopus Energy and verify your tariff is showing correctly.

Step 2: Configure Charging Windows

In your battery settings, set up charging windows that align with your off-peak periods:

// Example charging schedule configuration
const chargingSchedule = {
  windows: [
    { start: "00:30", end: "04:30", targetSoc: 100 },
    { start: "12:00", end: "14:00", targetSoc: 80 } // Solar top-up
  ],
  minimumSoc: 20,
  exportDuringPeak: true
};

Step 3: Set Discharge Rules

Configure your battery to discharge during peak hours:

1. Go to Devices > Battery > Schedule
2. Enable "Peak Shaving" mode
3. Set peak hours: 16:00 - 19:00
4. Set minimum reserve: 20%

Illustrative Savings Example

Here's a hypothetical calculation showing potential savings for a 10kWh battery (actual results will vary based on your tariff, usage patterns, and system):

Without optimization:

• Daily consumption during peak: 8kWh × 35p = £2.80

With optimization:

• Charge 8kWh at off-peak: 8kWh × 8p = £0.64
• Potential daily savings: £2.16

Note: These figures are illustrative. Your actual savings depend on your specific tariff rates, consumption patterns, and battery capacity.

Advanced: Agile Price Tracking

For Octopus Agile users, OhmMy can automatically:

1. Monitor upcoming 48-hour prices
2. Identify the cheapest charging windows
3. Adjust charging schedules dynamically
4. Alert you to negative pricing events

Enable this in Settings > Automation > Smart Charging.

Monitoring Your Results

Track your savings in the OhmMy dashboard:

• Cost Avoided - Money saved by using battery during peak
• Grid Import - How much you're drawing from the grid
• Self-Consumption - Percentage of solar used directly
• Arbitrage Profit - Savings from buy-low-sell-high strategy

Troubleshooting

Battery not charging during off-peak?

• Check your inverter's time settings are correct
• Verify the charging schedule is enabled
• Ensure grid charging is permitted in battery settings

Not discharging during peak?

• Check minimum SoC isn't set too high
• Verify discharge schedule is active
• Some inverters need "force discharge" enabled

Next Steps

Once you've mastered basic scheduling, explore:

• Solar forecasting integration
• EV and battery coordination
• Export optimization for SEG payments