The short answer
A solar battery is connected to a home system in one of two ways. In a DC-coupled setup, the battery works through a hybrid inverter that manages both the panels and the battery in one unit — usually chosen when solar and storage are installed together. In an AC-coupled setup, the battery has its own battery inverter and is added alongside an existing solar inverter — the common way to retrofit storage to a system fitted earlier. Either way, the battery is wired into your home's electrical system via the inverter and a connection at the consumer unit, with metering so it can charge from surplus solar (or cheap off-peak grid power) and discharge when you need it. The work must be done by a qualified electrician/installer, and the battery is sited somewhere ventilated and within its temperature range.
Adding a battery is mostly about how it ties into your inverter and consumer unit. The two coupling methods suit different situations — this page explains both and what installation involves.
Key facts
- DC-coupledBattery via a hybrid inverter (one unit)
- AC-coupledBattery with its own inverter (retrofit)
- Connects atThe inverter and the consumer unit
- Can charge fromSurplus solar or off-peak grid power
- Who fits itA qualified electrician / installer
DC-coupled: the hybrid inverter route
In a DC-coupled system, a single hybrid inverter handles everything. The panels' DC output, the battery's charge and discharge, and the conversion to AC for the home and grid all run through that one device. Because the panel electricity can charge the battery directly as DC, without being converted to AC and back, this approach is efficient and tidy.
DC coupling is the natural choice when you install solar panels and a battery at the same time, since you fit one hybrid inverter from the outset rather than two separate units. It also leaves a clean path to managing solar, storage and export together. If you are planning a new installation and know you want storage now or soon, specifying a hybrid inverter up front avoids paying for a second inverter later.
AC-coupled: the retrofit route
An AC-coupled system adds a battery that has its own dedicated battery inverter, working alongside the existing solar inverter rather than replacing it. The solar inverter still converts panel DC to AC for the home; when there is surplus AC, the battery's inverter converts it back to DC to store, and reverses the process to discharge.
This is the usual way to retrofit a battery to a solar system that was installed earlier without one, because it does not require replacing the original inverter. It is slightly less efficient than DC coupling because of the extra conversion step, but the difference is modest and it makes adding storage to an existing array straightforward. Many UK homeowners take this route, fitting solar first and adding a battery once they have seen their generation and usage patterns.
The reason AC coupling has become the standard retrofit approach is that it leaves the existing array untouched: the original solar inverter keeps doing its job, and the battery simply bolts on alongside with its own inverter. That means a battery can be added years after the panels went up, without disturbing a working installation or writing off equipment that still has plenty of life in it. The small efficiency penalty from the extra conversion is usually a price worth paying for that flexibility, which is why so many households defer the battery decision until they understand their own pattern of use.
| Method | How it connects | Best for |
|---|---|---|
| DC-coupled | One hybrid inverter for panels + battery | Installing solar and battery together |
| AC-coupled | Separate battery inverter alongside solar inverter | Retrofitting a battery later |
Comparison for guidance only. Source: Energy Saving Trust.
What the installation involves
Whichever method is used, the battery is wired into your home's electrics through the inverter and a connection at the consumer unit, with appropriate protection and metering so it can charge and discharge correctly. Modern batteries also accept charge from the grid, so the setup typically allows charging from cheap off-peak electricity overnight as well as from surplus solar.
The work is an electrical installation and must be carried out by a qualified electrician or accredited installer — it is not a DIY job, given it involves the consumer unit and a high-capacity battery. The battery itself needs siting somewhere suitable: ventilated, within the manufacturer's temperature range, and accessible for maintenance, often a garage, utility room or plant space. A reputable installer handles the grid notification and any certification, and commissions the system so it charges and discharges as intended. Once connected, the battery operates automatically according to its settings, storing surplus and releasing it when the home needs it.
Siting, safety and commissioning
Where the battery goes and how it is set up matter as much as how it is wired. A home battery is a substantial piece of equipment, so siting follows a few sensible rules:
- Ventilation and temperature. Batteries perform and last best within a manufacturer-specified temperature range, so they are placed somewhere that does not get extremely hot or cold and has adequate airflow — commonly a garage, utility room or dedicated plant space.
- Access. The unit needs to be reachable for maintenance and inspection, and not boxed in.
- Safe location. Installers follow manufacturer and industry guidance on where lithium-ion batteries may be mounted, which can rule out certain indoor positions such as habitable rooms or escape routes.
Once installed, the system is commissioned: the installer configures how the battery behaves — for example, prioritising storing surplus solar, or charging from a cheap overnight tariff and discharging at peak times — and confirms it charges and discharges correctly. They also handle the required grid notification and provide the certification you keep with your installation records. Modern batteries are then largely self-managing, running to their settings and reporting through an app, so day to day you simply benefit from stored energy without intervening. The combination of correct connection, careful siting and proper commissioning is what makes storage safe and effective, which is exactly why it is a job for a qualified installer rather than a DIY project.
Frequently asked questions
Can I add a battery to my existing solar panels?
Yes. An AC-coupled battery, which has its own inverter, can be retrofitted alongside your existing solar inverter without replacing the panels or the original inverter. This is the common way to add storage to a system fitted earlier. Many homeowners install solar first and add a battery once they understand their usage.
What is the difference between DC-coupled and AC-coupled batteries?
DC-coupled batteries work through a single hybrid inverter that manages both panels and battery, which is efficient and suits installing both together. AC-coupled batteries have a separate inverter and are added alongside an existing solar inverter, ideal for retrofits. AC coupling has a small extra conversion loss but makes retrofitting simple.
Can I install a solar battery myself?
No — it is an electrical installation involving the consumer unit and a high-capacity battery, so it must be done by a qualified electrician or accredited installer. They also handle grid notification, certification and commissioning. DIY installation would be unsafe and would likely invalidate warranties and any export arrangements.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific home. They are guidance, not a quotation or guaranteed saving.