How to Add Battery Storage to an Existing Solar System

Many factories and commercial buildings already have solar panels installed. However, without battery storage, excess solar energy may be exported to the grid or wasted through curtailment.

Can you add batteries without replacing your existing solar inverters?

In many cases, yes.

1. AC-Coupled ESS: Keep Your Existing Solar System

One of the simplest ways to add battery storage is through AC coupling.

System Architecture:

Existing Solar Panels → Existing PV Inverters → AC Bus

KOODSUN Battery → PCS → AC Bus

AC Bus ↔ Factory Loads / Utility Grid

This allows the existing solar system and the new ESS to work together.

Main Benefits:

• Keep existing solar inverters

• Store excess solar energy for later use

• Reduce peak electricity demand

• Use stored energy during expensive electricity periods

• Support backup power when properly configured

2. Can the System Work During a Power Outage?

Not automatically.

Most conventional grid-tied solar inverters shut down when the utility grid fails.

If backup power is required, the system may need a grid-forming PCS, EMS, switching and protection equipment, and compatible existing PV inverters.

The complete system must be evaluated to ensure safe operation during a blackout.

3. What If You Want to Add More Solar Panels?

If you plan to expand both solar and battery capacity, a hybrid solution may be suitable.

For example:

Existing PV → Existing Grid-Tied Inverters → AC Bus

New PV + Battery → Compatible Hybrid Inverter → AC Bus

This combines AC coupling with DC-side solar and battery integration.

4. How Do You Choose the Right Battery Capacity?

Battery capacity should be based on actual electricity consumption, not simply on existing solar capacity.

For example, a factory with 400kWp solar panels does not necessarily need a 400kWh or 1MWh battery.

The correct ESS size depends on:

• Maximum load (kW)

• Daily electricity consumption (kWh)

• Daytime and nighttime energy usage

• Available excess solar generation

• Required backup hours

• Electricity tariffs and grid conditions

These factors help determine the appropriate PCS power (kW) and battery capacity (kWh).

5. KOODSUN ESS Solutions

KOODSUN provides high-voltage lithium batteries, outdoor C&I ESS cabinets and containerized BESS solutions for commercial and industrial applications.

Whether you want to increase solar self-consumption, reduce electricity costs or add backup capability, we can help evaluate a suitable ESS configuration.

Already Have Solar? Let's Add Storage.

Send us the following information:

• Existing solar capacity (kWp)

• Inverter brand and model

• Grid voltage and frequency

• Maximum load (kW)

• Daily electricity consumption (kWh)

• Required backup time, if applicable

KOODSUN can help you evaluate the appropriate battery capacity, PCS power and system architecture.

Email: admin@koodsun.com

WhatsApp: +86 18119685462

KOODSUN | Lithium Battery & ESS Solutions