Solar Battery Storage

Adding batteries to a solar installation lets you use at night the energy generated during the day and have backup during power cuts. It is the natural complement to self-consumption, especially interesting in homes with night-time consumption or in areas with frequent outages.

We size the battery to your real consumption so the investment pays off, and check compatibility with your inverter. If needed, we propose a hybrid inverter that integrates the storage, leaving the system ready for backup mode.

We also add batteries to systems installed by other companies. The first step is reading the existing inverter's data: that tells us whether it accepts storage as it stands, with an additional module, or not at all.

Capacity is not calculated from the kWp installed but from what you consume between sunset and the following morning. That figure is on your bill or, better, in the hourly curve the distributor publishes in your customer area. From that curve you subtract what solar production already covers, and what remains is what is worth storing.

Oversizing is the expensive and most common mistake: a battery that never fully discharges does not return the share of the investment tied up in that idle capacity. It is also worth looking at the depth of discharge the chemistry allows, because usable kWh are always fewer than nominal ones, and comparing the cycles the manufacturer declares against the years you expect to keep the equipment.

A battery connected to an ordinary grid-tied inverter will not give you light during a power cut. For safety, the inverter disconnects when the grid disappears — so as not to feed it back while the utility works on it — and the battery and panels stop with it. This is the most common surprise for anyone who bought storage with blackouts in mind.

For real backup you need a hybrid inverter with an emergency output and a separate circuit in the panel carrying the loads you want to keep: fridge, lighting, router, a socket or two. That circuit is decided before installation, because it needs its own wiring. Be realistic about what hangs off it: air conditioning or an induction hob will empty a domestic battery in short order.