How Big are Home Battery Storage Systems?

A common concern for people moving towards sustainable energy systems in their home is size; and not just the size in terms of energy capacity, but the physical size of the units and how much space they take up. 

Whether it’s heat pumps, electric water heaters or solar panels, they all seem to be quite bulky. With roof mounted solar arrays it’s largely fine as they’re out of the way, but what about domestic battery energy storage systems? What are their typical dimensions and how much room do they really take up?

Like most things, the answer depends. With a battery’s physical size, the answer depends on its total energy storage capacity, the technology used and the brand design. 

This article will dig into the standard ranges of battery dimension, plus the other considerations that come with the full system. We’ll also look at a few specific brand examples, as well as their weights to give you the full picture on size.

How battery energy storage systems work in the home

Residential battery energy storage systems (BESS) are becoming more popular as homeowners look for ways to maximise their solar energy usage and reduce their reliance on the grid. BESS typically pair up with renewable energy sources like PV panels, but storage batteries can be used without a solar panel connection too. 

For battery energy storage systems that are solar connected, the battery stores any excess energy generated by solar panels during the day, allowing you to use that energy during times when the sun isn’t shining.

Battery storage systems come in various sizes and capacities, largely depending on the household’s energy needs and the solar set up. But they usually range in capacity from 3kWh to 15kWh. Alongside the battery itself, you’ll need a control box and at least one inverter depending on your connection (or not) to solar PVs. It’s the inverter that switches stored DC electricity or that generated by solar panels into usable AC electricity.

There are plenty of benefits to battery storage systems, with some of the main ones including:

• Maximising solar panel efficiency 
• Reduced energy bills
• Earn money by selling excess energy back to the grid

As battery technology continues to improve and costs continue to decline, domestic battery storage is becoming an increasingly attractive option for homeowners looking to become more cost and energy efficient. For many, it’s a no-brainer investment.

What is the average size of a home battery storage system?

The size of a residential battery energy storage system will depend on energy requirements and battery capacity. 

For a system with a capacity of at least 6kWh, which will provide the energy for some but not all of your electrical needs, you can expect the dimensions to fall in the range of:

• Height: 65cm – 120cm
• Width: 45cm – 85cm
• Depth: 12cm – 30cm

To put that into perspective, you can expect the physical dimensions of a residential battery storage system to fall somewhere within the range of a thin suitcase to that of a tall fridge freezer unit.

It’s possible to get smaller batteries installed that provide emergency power during outages. However, the majority of larger systems are designed to integrate with renewable energy installations, like solar panels. These bigger units offer greater storage capacity but also require more physical space.

It’s worth saying that manufacturers are continuously working to improve the energy density of battery storage systems. The goal here is to pack as much energy storage into as little space as possible. As energy density improves, smaller units are created. 

How much space do you need for battery storage?

When installing a battery storage system, it’s not just the battery itself that you’ll be installing. You’ll also have a control box and potentially a separate inverter (or two), depending on your set up. Some inverters, such as those integrated into the Tesla Powerwall, are built into the unit itself. 

As a guide to the space needed for installation, the battery inverter and batteries should be within 1m of each other.

You’ll also need to leave appropriate spacing for heat dissipation and safety considerations, as will be outlined in the manuals, as well as account for switches, fuse boxes and cables.

With all this in mind,  it’s essential to have a good open area with a solid wall, not just a corner or the exact space for the physical dimensions of the battery unit and nothing else.

The best locations for a home battery system

I bet you’re assuming that your battery storage needs to go in the loft aren’t you? 

Well, not necessarily. When it comes to finding the best location for your home battery system, there are a few factors at play. 

The ideal spot should be close to your main consumer unit (fuse box) and have enough space to accommodate the battery, inverter and other components discussed above. Some common locations for installing a home battery system include:

• Lofts – This is the most popular place. Mainly because batteries are often installed alongside solar arrays and the loft is where the solar inverter is. You also have plenty of spare space in the loft in most cases. However, it’s worth noting that the battery system’s main function is to monitor the grid connection, not the solar panels directly.
  
• Utility rooms – Good spaces, often close to existing electrical systems. This makes it easier to connect the battery to the consumer unit with less cabling.
  
• Cupboards – Dedicated storage spots, such as under-stairs cupboards or hall cupboards, can work well provided they have adequate ventilation to prevent overheating.
  
• Garages – Can be another good location for battery systems as garages tend to have plenty of space. However, it’s likely you’ll have to run a long cable which can pose issues. 

The battery storage positioning will depend on the physical circumstances of your home. Wherever it goes, it should be:

• Accessible for maintenance
• A location with moderate temperature fluctuations to optimise performance and lifespan
• Well-ventilated to prevent overheating
• Away from areas prone to moisture

How much do battery storage systems weigh?

The weight of residential battery systems can vary considerably depending on their capacity and design. One thing is clear though, they’re not light. 

Most modern storage systems use lithium-ion batteries. These are the same types of batteries found in mobile phones and electric vehicles. Lithium-ion batteries have a good energy density, meaning they can store a lot of energy for their size. It just means they’re heavier than they look most of the time.

Generally speaking the bigger the storage capacity, the heavier the system will be. For a ballpark figure, standard home battery storage units typically range from 50kg to 150kg. 

At this weight, you need a suitably strong wall to attach the battery to, as well as a solid floor to take the load. You can see example weights in the table below.

Home battery storage system examples

Hopefully, that gives you a good idea on how big battery energy storage systems are and how much space they’re likely to take up in your home.