Adding a battery to an existing solar system
You already have panels. Under Net Billing, storage is often what makes them properly worth having. Here is what a retrofit actually involves.
Many systems in Cyprus were installed before storage was a normal part of the conversation, or under Net Metering, when export was worth the same as consumption.
Under Net Billing that arithmetic has changed, and a lot of existing installations are now exporting energy at a fraction of what the same unit costs to buy back in the evening.
That gap is what a retrofit closes.
What determines whether it is straightforward
Everything depends on the inverter you already have.
Hybrid inverter, battery-ready
The simplest case. The inverter already has a battery port and the storage connects directly. Often the work is a day, plus the EAC side.
Grid-tied inverter, no battery port
Most older installations. The battery gets its own AC-coupled inverter working alongside the existing one. Both systems run in parallel and the panels stay exactly as they are.
Inverter near end of life
If the existing unit is old or unreliable, replacing it with a hybrid can cost little more than adding a second inverter, and leaves a simpler system with one point of control.
Not worth retrofitting
It happens. A very small array, or one badly shaded, may not generate enough surplus to fill a battery. We say so rather than sell you storage that will sit half empty.
What we check before quoting
- Inverter make, model and age — this decides the whole approach
- Actual array size and orientation, and how much surplus it genuinely produces
- Your consumption pattern from recent bills, because a battery is only worth what it displaces
- Supply type and existing EAC arrangement
- Space and location for the battery, including ventilation and temperature
- Whether you want backup, which is a separate design decision from storage itself
Storage and backup are not the same thing
This is the most common misunderstanding we correct. A battery fitted for self-consumption will shut down with the grid during a power cut unless the system was specifically designed for islanded operation.
If keeping the house running during an outage matters to you, say so at the start. It changes the inverter choice and the switchboard work, and it is far cheaper to build in than to add later. Our backup page covers that side in detail.
Is it worth it on the numbers
Sometimes clearly yes, sometimes not. It depends on how much surplus your existing array produces and how much of your consumption sits after sunset.
We wrote a worked comparison showing when storage earns its cost and when it does not, using real modelled figures: bigger array or a battery? The same logic applies to a retrofit, except you have already paid for the panels, which usually improves the case.
Our cost calculator will model your consumption under Net Billing with and without storage.
Equipment
We work mainly with KSTAR hybrid inverters and LFP batteries using CATL or EVE cells. For retrofits onto other brands, we assess compatibility case by case rather than assuming one approach fits every existing installation.
Frequently asked questions
Related
Send us your inverter model and a recent bill. We will tell you honestly whether it is worth it.