October 09, 2025

If you’re an Irish homeowner considering solar for your home, you’ve likely wondered about battery storage, and how it works.

A solar battery stores the excess electricity your solar panels produce so you can make greater use of your own self-generated electricity later, typically at night or during peak-rate periods when household use exceeds production.

Battery storage isn’t for everyone, some households get better value from exporting unused electricity or hot water diversion.

In this article, we will explore how battery storage works, the key components involved, when it makes sense (and when it doesn’t), and the simple checks to help you decide if it’s right for your home.

1. What is Solar Battery Storage?

Think of a solar battery as a rechargeable battery home power pack. Your solar PV panels generate electricity during daylight hours. Your home uses what it needs first. Any extra can be stored in the battery for later, rather than being exported to the grid.

At night or during periods of low energy production, your battery can be used to power your home. This means you can make use of your self-generated electricity rather than buying power from the grid.

2. How Does it Work?

1. Generation: Your solar panels absorb daylight to produce direct current (DC) electricity.

2. Conversion: An inverter converts the DC electricity into alternating current (AC) that powers your home’s appliances.

3. Priority: Your home’s live demand is met first.

4. Charging: Any surplus charges the battery (subject to settings).

5. Discharging: In the evening or during peak rates, the battery powers your home.

6. Grid interaction: If the battery is full, any extra is exported. If the battery is empty and demand exceeds generation, you import from the grid.

7. Optional time of use: With smart settings, you can top up the battery from cheaper night rates and avoid buying electricity at peak times.

3. The Key Components

• PV array: Your solar panels on the roof or ground mount.
• Inverter:
• Hybrid inverter: Manages both PV and battery on one unit.
• AC-coupled battery inverter/charger: A separate box that adds a battery to an existing PV system.
• Battery module(s): The cells that store energy, usually lithium‑iron‑phosphate (LFP) in modern home systems.
• BMS (Battery Management System): Protects the battery, controls charge/discharge, prolongs life.
• Gateway/backup switch (optional): Electrically isolates a backup circuit during power cuts to keep selected circuits on.
• Monitoring app/portal: Lets you view generation, battery state of charge (SoC), and change settings.

4. Where is The Battery Installed?

In Irish homes, battery storage is often installed in utility rooms, under-stairs, garages, or in the hall. The location of the battery must meet the manufacturer’s temperature and access requirements.

Installers allow for:

• Adequate clearances and ventilation per manufacturer guidance.
• Wall strength and mounting. Many systems are wall‑mounted; some are floor‑standing.
• Cable routes to the consumer unit, inverter, and meter.
• Noise & access: Batteries and inverters are generally quiet but not silent; you’ll want maintenance access.

5. When Battery Storage Makes Sense (and When it Doesn’t)

Battery storage could be a good fit for your home if you:

• Use most of your electricity in the evenings (family at home after 5–6 pm).
• Have time‑of‑use tariffs (day/night or multi‑period rates) and want to avoid peak imports.
• Own an EV and want to charge partly from solar or cheap night rates buffered by the battery.
• Run a heat pump and cut running costs.
• Experience occasional outages and want backup (with the right hardware).

Battery storage may be less ideal for your home if you:

• Are home and using appliances mostly during the day.
• Have very low evening consumption (little to store/use later).

6. Sizing Your Battery: A Simple Method

Two numbers matter:

• Capacity (kWh): The size of stored energy.
• Power (kW): The max rate it can charge/discharge. Power affects whether it can cover several appliances at once.

Quick sizing approach:

1. Check a few weeks of evening usage (e.g. 5 pm–11 pm) on your electricity bills/app.

2. Take a typical evening total, for example 5 kWh.

3. Choose a battery roughly equal to that figure. This often balances cost, usage, and cycling.

4. If you plan to charge from cheap night rates, a slightly larger battery can make sense.

If considering backup, also check the required power (kW) to run your chosen circuits (fridge/freezer, lights, Wi‑Fi, some sockets, maybe a gas boiler or small heat pump).

Usable vs nominal capacity: Manufacturers quote nominal kWh. Actual usable kWh may be slightly lower due to depth‑of‑discharge limits and BMS reserves.

7. What happens during a power cut?

When a power cut occurs, your home disconnects from the ESB grid.

This is a safety feature, protecting both your household and the technicians working to fix the problem. In most cases, if your solar system is connected to the grid (as the majority are), it will also shut down during an outage.

Power cuts in Ireland are relatively rare and usually short. That said, storm damage, fallen trees, or planned maintenance can cause interruptions that last several hours, days, or longer in rural areas.

This means that without a battery and a power backup system, you will not be able to use any of your solar energy during a power cut.

Backup power is possible, with a battery and a backup system, but this needs careful design.

There are still limitations to backup power, however you will be able to keep the essentials running, such as fridges, freezers, Wi-Fi and lighting.

Backup systems are designed to cover the essentials, not to run your entire house indefinitely. Battery capacity, inverter size, and the amount of stored energy all play a role.

8. Safety, standards & good practice

• Chemistry: Many home batteries now use LFP (lithium‑iron‑phosphate) which is valued for its thermal stability and long cycle life.
• Location & mounting: Follow manufacturer guidelines, away from ignition sources, with secure fixing and access.
• Protection: Correct fusing/isolation, RCD/RCBO arrangements, and earthing as per standards.
• Competent installer: Work should be completed and certified by qualified and reputable professionals using compliant equipment.
• Housekeeping: Keep the area dry, tidy, and accessible, don’t store anything flammable beside the unit.

Read this article to learn more about how to choose a reputable installer.

9. Lifespan, warranties & degradation

Cycle life: Many systems warrant 6,000–10,000 cycles or 10 years, whichever comes first (exact terms vary).

Degradation: Expect gradual capacity reduction over time. After the warranty period, many batteries still retain a useful percentage of original capacity.

Settings matter: Avoiding repeated full‑to‑empty swings at maximum power and extreme temperatures helps longevity.

Read this article to learn more about the lifespan of battery storage and other solar system components.

10. Costs & what drives them

Exact prices vary, but the main drivers are:

• Battery capacity (kWh) and inverter power (kW).
• Hybrid vs AC‑coupled: Adding a battery to an existing system can need extra hardware.
• Backup hardware: Gateways, additional switching, and labour for a backup circuit.
• Installation complexity: Cable routes, consumer unit upgrades, isolators, meter box access.
• Brand ecosystem & features: Apps, integrations, smart tariff control, future expandability.
• Value lens: A well‑matched battery can reduce peak imports, increase self‑consumption, and improve comfort (backup). Oversizing or under‑utilising can reduce financial return.

11. Alternatives to consider

• Hot water diverter: Uses surplus solar energy to heat your cylinder; simple and often very cost‑effective.
• EV smart charging: Schedule your EV to charge during cheap periods or sunny windows.
• Demand shifting: Run dishwashers, washing machines, and dryers during solar‑rich hours.
• Add PV capacity: In some homes, a slightly larger array offers more annual benefit than a battery.

12. Installation: What To Expect

• Survey & proposal: Your installer reviews load patterns, goals (backup or not), and location options.
• System design: Choose hybrid vs AC‑coupled, battery size, and any backup circuits.
• Grid notification & metering: Your installer handles the necessary notifications and coordinates any meter works as required.
• Installation: Mounting, wiring, commissioning, and app setup.
• Handover: You get documentation, warranty info, and training on the app and settings.
• Monitoring & fine‑tuning: Small setting tweaks over the first weeks (e.g., charge windows, backup reserve).

Read this article to learn more about how solar systems are installed.

13. Maintenance, monitoring & troubleshooting

Batteries are largely set‑and‑forget. Make sure to keep the area clean and accessible and ensure the firmware is updated.

Use the app to track state of charge, charge and discharge windows, and export and import trends.

Common issues are Wi‑Fi drops (monitoring offline), incorrect time‑of‑use schedules, or settings that cap charging/discharging. Your installer can help advise you on this.

Read this article to learn more about how to maintain your solar system.

14. Quick decision checklist

• Do we use 3-8 kWh most evenings?
• Are we on a time‑of‑use tariff (or planning to switch)?
• Do we own/plan to own an EV or heat pump?
• Do we want backup power in the event of a power outage?
• Do we have space and a sensible install location?
• Will a hot water diverter meet our goals at lower cost?
• Have we picked a reputable installer and read the warranty terms?

15. FAQs

Q: How big should my battery be?

A: Start with one typical evening’s usage (e.g., if evenings average 5 kWh, look at ~5 kWh usable). Adjust up if you plan to top up on cheap night rates or want longer backup.

Q: Can I add a battery to my existing solar?

A: Yes. Contact your solar installer to enquire about add-ons.

If you’re still planning your PV, a hybrid inverter can simplify wiring.

Q: Will it power my whole house in a blackout?

A: Only if designed that way. Many homes choose a backup sub‑board (lights, fridge/freezer, broadband, some sockets). Whole‑home backup needs careful design and may not cover high‑draw appliances.

Q: How long does a battery last?

A: Many carry 10‑year warranties with cycle limits. Real‑world life depends on usage patterns and environment.

Q: Is a battery worth it in Ireland?

A: It depends on your evening use, tariffs, export payments, and goals (comfort/backup vs pure payback). Some homes get better value from hot water diversion or smart EV charging.

Q: Do I need a smart meter?

A: A smart meter isn’t strictly required for a battery to operate, but you do need one if you want to export electricity back to the grid. Having a smart meter also helps you take advantage of time-of-use tariffs and provides more accurate tracking of both imports and exports.

16. Final Thoughts

Solar battery storage is most effective when it’s right-sized to your evening habits and configured to your tariff.

If you’re unsure, start with data: review a few weeks of evening usage, consider your tariff options, and discuss backup priorities with a reputable installer.

A clear, evidence-based plan will help you choose the simplest solution that meets your goals, without over-spending or over-complicating your system.

Ready to take the next step?

If you’re considering battery storage as part of your solar system, the best place to start is with an in-person consultation to discuss your own home’s electricity, needs and goals.

Fill out the form below to book a free consultation with our team.