BrightGridIf you already have solar panels, you do not necessarily need to replace the entire system to add battery storage. The most suitable retrofit approach depends on your existing inverter, system architecture, battery compatibility and electrical installation.
AC-coupled battery retrofit
An AC-coupled battery system can operate alongside an existing solar inverter using its own battery inverter. This can be useful where the existing solar system is still performing well.
DC-coupled battery system
DC-coupled architectures can connect the battery more directly within the DC side of the energy system, often through a compatible hybrid inverter.
| Approach | Potential advantage |
|---|---|
| AC-coupled | Can retain an existing solar inverter |
| DC-coupled | Can integrate solar and battery through compatible hybrid equipment |
What needs to be checked?
- Existing inverter
- Solar system capacity
- Battery compatibility
- Electrical protection
- Consumer unit
- Available installation space
- Monitoring
- DNO requirements
Why retrofit a battery?
A battery can increase the amount of solar electricity available during the evening and may provide additional tariff flexibility.
Do not assume your existing inverter is battery-compatible
The installer should inspect the existing system before recommending a battery and determine whether AC coupling, a hybrid upgrade or another architecture is appropriate.
Add battery storage to existing solar
Assess your existing inverter and solar installation to find the most suitable retrofit battery option.
Explore Battery RetrofitFrequently asked questions
Can I add a battery to existing solar panels?
Yes, many existing solar systems can be retrofitted with battery storage, subject to compatibility and electrical requirements.
Do I need to replace my solar inverter?
Not necessarily. An AC-coupled battery can sometimes operate alongside an existing solar inverter.
What is AC coupling?
AC coupling uses a separate battery inverter connected on the AC side of the existing solar system.
Is adding a battery to old solar worth it?
It depends on the existing system, electricity consumption, battery cost and expected additional value.
Marcus Webb
Head of Engineering at BrightGrid Energy
