Can I Add a Battery to My Solar System?

As battery technology continues to evolve and the price of solar batteries decreases, we see an increase in demand for adding a solar battery to an existing residential solar system.

Homeowners are recognising the benefits of solar energy storage, such as increased energy independence, reduced reliance on the grid, and enhanced resilience during power outages. This shift not only allows users to store excess solar energy generated from your solar panels on sunny days for use at night or use during cloudy days but also contributes to a more sustainable energy future.

Naturally, we get plenty of questions from homeowners asking “can I add a battery to my existing solar system?” The good news is, you absolutely can add a solar battery to an existing solar panel system! In this article, we’ll explain the two main ways of how you can add a battery to an existing solar system.

Why would you want to add a solar battery to an existing solar system?

Adding a solar battery to an existing solar panel system offers numerous benefits including:

• Increased energy independence: Store excess solar energy and use it when needed, reducing reliance on the grid.
• Lower energy bills: Use stored energy at night or during peak hours, minimising your electricity costs.
• Backup power: Maintain power during grid outages, ensuring uninterrupted energy for your home.
• Maximised solar efficiency: Utilise more of the energy your system generates rather than sending it back to the grid.
• Future-proof your solar system investment: As energy prices rise, a solar battery helps secure long-term savings and sustainability.

The two main types of solar battery storage systems

The two main types of batteries you can add are AC-coupled battery systems and DC-coupled battery systems or otherwise known as hybrid systems. Both options provide great benefits, but the right choice depends on your current setup and energy needs. Here’s an overview of how each option would allow you to add a battery to an existing solar panel system.

Option 1. Replace the old inverter with a hybrid inverter to add a solar battery to an existing system

Replacing your old solar inverter with a new hybrid inverter and adding compatible solar batteries designed specifically for it offers many advantages. Contrary to popular belief, a DC coupled hybrid system can be more affordable than an AC coupled system battery.

Benefits of replacing an old inverter with a hybrid inverter

1. Designed to work together

One of the key benefits of opting for a hybrid inverter with matching solar batteries is that they are designed to work seamlessly together. This integration ensures higher energy efficiency and performance.

2. Simplified diagnostics

If there’s ever a concern about your system’s health or performance, dealing with one solar company for diagnosis eliminates any blame games. The system is more easily monitored and maintained by the original manufacturer, which can be crucial when dealing with complex technical factors that may challenge the average user.

3. Backup power in grid failures

Most hybrid inverters paired with solar batteries have the capability to operate as stand-alone systems. This means that during grid failures, if your batteries are not fully discharged, your solar panels can continue charging them, allowing you to keep running until the grid power is restored.

4. Enhanced power distribution

Unlike most AC batteries, hybrid inverter systems with matching solar batteries provide more even power backup, especially in setups with three-phase metres. This makes them a more reliable option during power outages.

Disadvantages of upgrading your inverter to add a solar battery to an existing system

The only downside to this approach is that battery manufacturers may release newer models in the future, which may not be compatible with your existing solar system. If you plan to expand your solar battery storage years later, you might find that the newer models aren’t suitable for your older system.

Option 2. Adding AC batteries to your grid connect inverter to add a solar battery to your system

Adding an AC battery to a grid-connected solar system is a flexible and convenient option for homeowners who want to expand their energy storage without replacing their existing inverter. This solution is also ideal for those who only want to install solar panels and want to add battery storage later.

Benefits of adding AC batteries to an existing inverter

1. Increased flexibility

One of the key advantages of adding AC batteries to an existing grid connected inverter is the flexibility it offers. This solution might even be more affordable in the future, especially if you’ve recently invested in a high-quality inverter and don’t wish to replace it.

2. The popularity of AC batteries

Two of the most recognised names in AC batteries include the Tesla Powerwall and Alpha ESS. However, the market is still emerging, and there aren’t too many solar battery brands offering a wide variety of options yet. This could change as competition grows, benefiting buyers in pricing and choice.

3. AC batteries work with grid inverters

A little-known fact is that AC batteries come with built-in inverters that work in tandem with existing grid connect inverters. This feature, however, makes AC batteries a more expensive option compared to replacing the current grid inverter with a hybrid system.

Disadvantages of adding AC batteries to an existing solar system’s inverter

1. Modularity and installation costs

While AC batteries are popular, their modularity isn’t as ideal as hybrid systems. Every time an additional AC battery is added, extra electrical work is required, which can drive up installation costs. Moreover, backup capabilities are limited for homes with three-phase metres, as only one phase is supported.

2. Power backup limitations for larger households

For larger households, the inability of multiple AC batteries to sync between phases can be problematic during power outages. While this is a less common issue, it’s important to consider for homes with high power needs and three-phase loads.

3. Recharging challenges during power failures

Another drawback of AC batteries is their inability to recharge via solar panels when the grid is down. Homeowners must wait for the utility company to restore power before their batteries can be recharged.

Is it worth adding a solar battery to an existing system?

As you can see, yes, it’s possible to add a battery to your solar system. And yes, it is worth it! With more solutions coming to market, driven by the growing demand for electric vehicle (EV) chargers, battery options are set to increase in both variety and affordability. There was a time when batteries weren’t considered cost-effective, but that view has drastically changed. Batteries are becoming essential due to the grid’s inability to keep up with rising electricity demands, leading to more frequent power outages.

As extreme weather events and hotter summers place more strain on the grid, backup power solutions like AC batteries are becoming the norm. From air conditioners in scorching heat to storms damaging infrastructure, the future is undoubtedly heading towards battery reliance.

Yes, you can upgrade your existing solar system to include a battery and we can help!

If you’re considering adding a solar battery to your existing solar power system, there’s never been a better time! Whether you’ve got an existing battery energy storage system that is too small or want to upgrade an existing solar panel system to include a battery, we’ve got tailored solutions for you! Don’t hesitate to get in contact with the friendly team at e-Solar for advice on upgrading your current solar panel system.