Do I Need Batteries For Solar Panels?

Benefits of Solar and Battery Storage

1. Energy Independence: Battery storage allows you to store excess solar energy generated during the day for use in the evening or on cloudy days, reducing your reliance on grid electricity.

2. Backup Power: During power outages, solar battery storage systems can provide a reliable source of electricity, so you can keep your essential appliances running.

3. Cost Savings: By storing excess energy and using it during peak demand or when electricity prices are high, you can save even more on your energy bills.

4. Maximise Solar Generation: Battery storage helps you get the most out of your solar generation by capturing excess energy that would otherwise be fed back into the national grid.

Battery Storage Considerations

Size and Capacity

The size of your solar battery system depends on several factors, including your energy usage patterns, the size of your PV system and your backup power needs. For UK homes, solar battery systems typically range from 5 kWh to 20 kWh in total capacity. To work out how many solar batteries you need, consider:

• Your daily energy usage

• The size of your solar panel system

• How energy independent you want to be

• If you plan to charge an electric vehicle

Cost

While the cost of solar panels has come down in recent years, battery storage is still a big upfront investment. But prices are getting cheaper as technology improves. Consider the long term savings on your energy bills when evaluating the cost.

Types of Solar Batteries

1. Lead-acid batteries: These are the most common and cheapest option, but have a shorter lifespan and lower efficiency compared to others.2. Lithium-ion batteries: These are the best solar batteries for most homeowners, higher efficiency, longer lifespan and better performance.

2. Flow batteries: These have a long cycle life and can be fully discharged without damage, but are more expensive and less common for residential use.

Compatibility

Make sure the battery storage system you choose is compatible with your existing solar panel system and inverter. Not all batteries will be suitable for your system. Consult with a qualified installer to assess compatibility and system sizing.

Do I Need Batteries for My Solar Panels?

Consider the following to decide if you need a home battery:

1. Energy usage patterns: If you’re a high user of energy in the evening, you will likely benefit from a battery.

2. Desire for energy independence: If you want to use less grid electricity and be more energy independent, battery storage is essential.

3. Electricity rates: If your area has time-of-use rates or high peak electricity costs, storing solar energy for use during peak hours can save you money.

4. Frequent power outages: If your area experiences regular grid disruptions, a battery system can provide valuable backup power.

5. Electric vehicle ownership: If you have an electric vehicle, a battery system can charge it using stored solar energy.

Do I Need Batteries for Solar Panels?

Solar panels work by harnessing sunlight to generate electricity which can be used immediately or stored for later use. Batteries are not necessary for solar systems but enhance energy storage, so you can store energy and use it during periods of low solar generation, such as evening or cloudy days. This setup can reduce your reliance on grid electricity and lower your energy bills.

How Solar Panels Work Without Batteries

Most solar systems are connected to the grid, so you can use electricity generated during the day and send excess back to the grid. In return you get credits through net metering, offsetting your energy bill. But without batteries you can’t store excess energy for off-grid use or backup power during outages.

How Big Solar Battery: What Capacity Do I Need?

Factors Affecting Battery Size

The size of your solar battery depends on:

• Energy Generated: Larger systems generate more energy and may need higher capacity batteries.

• Energy Usage: Your daily energy usage determines how many batteries you need.* Roof Space: The size of your PV system is limited by available roof space.

• Backup Needs: If you want to go off-grid or have power during outages, a larger battery capacity is required.

Typical Battery Sizes

For UK homes:

• Small Systems (2 kW): 4–5 kWh battery capacity.

• Medium Systems (4–6 kW): 8–12 kWh battery capacity.

• Large Systems (8–10 kW): 16–20 kWh battery capacity.

Choose the right size battery for optimal storage and cost efficiency. Oversized batteries waste money and space, while undersized ones limit savings on your energy bills.

Energy Storage Benefits

Energy storage systems allow households to store excess power generated during the day for later use. This reduces reliance on grid electricity and increases self-consumption of clean energy. Key benefits include:

1. Energy Independence: Store energy to reduce dependence on the national grid.

2. Cost Savings: Use stored energy during peak demand periods when grid electricity rates are higher.

3. Backup Power: Keep essential appliances running during outages.

Battery Capacity and Types

Types of Solar Batteries

1. Lead-Acid Batteries: Cheapest but lower lifespan and efficiency.

2. Lithium-Ion Batteries: Most solar batteries are lithium-ion due to their high efficiency and long cycle life.

3. Flow Batteries: Suitable for high-capacity needs but less common in residential markets.

Battery Capacity Explained

Battery capacity is measured in kilowatt-hours (kWh). Higher capacity batteries can store more energy but may cost more upfront. For example:

• 5 kWh battery can power basic household needs during evenings.

• 10 kWh battery is suitable for larger homes or those who want to go off-grid.

Off-Grid vs Grid-Tied Systems

Off-Grid Systems

Off-grid systems are entirely solar and battery based without connection to the national grid. They require higher capacity batteries to store enough energy for nighttime use and cloudy days.

Grid-Tied Systems

Grid-tied systems allow you to stay connected to the grid while using solar panels. Excess power is sent back to the grid and you can draw electricity when solar generation is low.

Other Factors to Consider

When choosing a battery system,1. AC vs DC: Ensure compatibility with your inverter.

1. Cycles: Battery lifespan depends on charge/discharge cycles; lithium-ion batteries last longer.

2. Market Trends: Prices are decreasing and efficiency is improving as technology advances.

Example Scenarios

1. A 4 kW system household might choose an 8–9 kWh battery to store excess energy generated during the day.

2. A 6 kW system household may opt for a 12 kWh battery for more energy independence and less grid reliance.

Conclusion

Battery storage isn’t necessary for every solar panel system but offers many benefits for many homeowners – energy independence, backup power and cost savings. Carefully consider your energy needs, budget and preferences to decide if battery storage is right for you.

Talk to a qualified solar installer to get tailored advice and guidance for your situation. Go solar and make an informed decision to optimise your energy usage, save money and reduce your carbon footprint.

Get in touch to request a free, no obligation quote from our team. We’ll get back to you within 1 working day to help you find the best solar and battery storage solution for your home.