Add a Battery to Your Existing Solar System
If you installed solar before batteries were common, you are likely exporting your best daytime generation for very little return. Feed-in tariffs across Moreton Bay and the Sunshine Coast are set by retailers rather than regulated, and typically run only 0–10 cents per kWh — averaging around 5–6 cents among the better offers. Adding a battery lets you store that same generation and use it yourself after dark, at full retail value instead of a few cents in export credit.
AC-coupled: the standard retrofit for an existing system
For a home or business that already has solar panels and a working inverter, an AC-coupled battery is almost always the right approach. Your existing inverter stays exactly where it is, and the battery connects into your switchboard on the household side, charging from whatever your existing system is already exporting. There is no need to touch the panels or the original inverter.
DC-coupled: only worth it if you are replacing the inverter anyway
A DC-coupled setup requires swapping your existing inverter for a hybrid unit, which is an additional cost of roughly $1,500–$3,500 or more on top of the battery itself. It is a genuinely better-performing setup — round-trip efficiency of 95–98% versus 89–94% for AC-coupled — but for most Australian households that efficiency gap only translates to an extra $50–$150 a year. Unless you are already replacing your inverter for another reason, AC-coupled retrofitting delivers nearly the same result for meaningfully less money.
What we check before recommending a battery size
- Your existing inverter's age, condition and export capacity
- Your actual daily and evening usage pattern, not just a generic household average
- How much of your current generation is already being exported versus self-consumed
- Switchboard capacity for the new circuit
- Whether AC-coupled or a hybrid DC-coupled upgrade makes more financial sense for your situation
Servicing Moreton Bay and the Sunshine Coast
SEBSS is based in the Moreton Bay region, with direct local reach across both Moreton Bay and the Sunshine Coast on the Energex network. Battery retrofit work is carried out under CEC accreditation and Electrical Licence 73850, including all network notification paperwork with Energex.
Frequently asked questions
Can any solar system have a battery added to it?
In almost all cases, yes, using an AC-coupled battery that connects independently of your existing inverter. The main exceptions are very old or non-compliant systems, which we would flag during the site assessment before quoting.
Is AC-coupled or DC-coupled better for my situation?
For most existing systems, AC-coupled is the more cost-effective choice since it avoids replacing your inverter. DC-coupled is worth considering only if your inverter needs replacing anyway, since it delivers a modest efficiency gain once you are paying for a new inverter regardless.
How much does it cost to add a battery to existing solar?
The battery and AC-coupled installation cost depends on the storage capacity you choose. If a hybrid inverter upgrade is needed for a DC-coupled setup instead, budget an additional $1,500–$3,500 or more on top of the battery cost. A site assessment gives you an exact figure for your system.
Will adding a battery void my existing solar warranty?
No, not when installed correctly by a licensed installer. An AC-coupled battery connects independently of your existing panels and inverter, so it does not interfere with their original warranty coverage.