Adding different types of batteries to your project

Summary:

OpenSolar now supports adding and modeling multiple types of batteries within a single project, enabling you to simulate more advanced and realistic battery configurations. This feature is ideal for scenarios where a system includes batteries of varying brands, sizes, or performance characteristics.

Note: All batteries added to a single design are modeled as part of the same system. If you need to simulate them separately (e.g., for different proposals or owners), create multiple proposals or systems instead.

How to Add Multiple Battery Types

To include different battery models in one system:

1. Navigate to the Design tab of your project.

2. Open the Battery section.

3. Click the + Battery icon.

4. In the pop-out panel, select the first battery model you want to include.

5. Repeat the process to add additional battery models to the same system.

There is no limit to how many different battery types you can include in a design, and all will be modeled together.

How Multiple Batteries Impact Energy Calculations

When multiple battery types are included in a project, OpenSolar aggregates their performance metrics and calculates a unified system profile. Here's how the modeling works:

Aggregated Metrics

• Total Energy
  Includes:

  • kWh Charge Capacity

  • Optimal and Degraded Energy Capacity

• Power Metrics

  • Peak Power

  • Continuous Max Power

• Warranty Capacity

  • Assumed at 1 cycle per day, calculated per system

Weighted Average Parameters

OpenSolar uses a capacity-weighted average to represent performance parameters across battery types, such as:

• Battery Aging Factor

• Depth of Discharge (DoD) Factor

• Efficiency (Total and One-Way)

• End-of-Life Capacity

• Usable Capacities (Standard and Degraded)

This approach ensures each battery’s contribution is reflected accurately in the system-wide performance.

Installer Note: Battery voltage does not affect the simulation. It is acceptable to include batteries with different voltages in the same design. However, be mindful of real-world installation implications.

Behind the Scenes: Detailed Calculation Methodology

Once battery specifications are added, OpenSolar performs hourly simulations to estimate system behavior, including charge/discharge cycles, capacity degradation, and usable throughput.

4 Key Input Areas

1. Battery Specifications

   • Charge/discharge rates

   • Degradation curve

   • Round-trip efficiency

   • Configured in Control > Design & Hardware > Batteries

2. Battery Control Scheme

   • Charge/discharge strategy

   • Reserved capacity for peak usage

   • Grid export logic

   • Custom schemes can be created

3. Connection Type

   • AC-coupled vs. DC-coupled

   • Influences PV oversizing and system configuration

4. Load Offset Settings

   • Defines how much of the site’s load the battery is allowed to offset

Modeled Outputs

Based on the inputs above, OpenSolar simulates:

• Usable Capacity
  Adjusted by depth of discharge (DoD) limits

• Charge & Discharge Behavior
  Limited by battery specs; surplus solar is exported if the battery is full

• Efficiency Losses
  Calculated using round-trip efficiency values

• Degradation Tracking
  Lifetime throughput reduces usable capacity over time

• Discharge Timing
  Follows the selected control scheme (e.g., load-following by default)