In short: off-grid is more than panels plus a battery
Off-grid means your house runs — partly or entirely — on your own sun and a battery, independent of the grid. On top of a standard installation, that calls for a few extra parts: a battery, a backup/changeover unit and some extra protection. The biggest extra outlay is almost always the battery; the rest is a few hundred euros of switchgear.
What else is involved
A grid-tied installation leans on the grid when the sun isn’t shining. Off-grid has to cover that itself, and that calls for:
- A battery — required for off-grid. During the day your sun charges it; in the evening and at night you draw on it. Straight away the biggest cost of an off-grid system.
- A backup/changeover unit — switches your home over to the battery seamlessly, within a second, so you notice nothing. It also decides which circuits (your critical loads) always stay powered.
- DC battery protection — a heavy-duty fuse or breaker that safely disconnects the battery.
- Usually a heavier or three-phase inverter — because your whole house runs off the inverter, not only off whatever the panels are producing at that moment.
- Optional: a generator connection — for that rare dark winter week. With an automatic changeover switch, a generator kicks in if the battery threatens to run flat.
Single-phase or three-phase?
That mostly depends on your existing connection, not on the number of panels. A single-phase connection (monofásico, 230V) is allowed in Spain up to around 14.5 kW — ample for most homes, even with a sizeable solar system. You need three phases (trifásico, 400V) if your home already has that connection, or if you draw a great deal of power at once: a large villa with several air-conditioning units, a pool and perhaps a heat pump. Three-phase spreads the load nicely; it’s a little dearer, and that’s built into the price estimate.
An honest picture: on top of a standard installation, the extra switchgear — the changeover unit, the battery protection and the heavier setup — comes to roughly a few hundred up to around a thousand euros, depending on the size and whether it’s single- or three-phase. On top of that comes the battery, and that’s the biggest item. In our price estimate you can pick off-grid and a battery, and you’ll see straight away roughly what it comes to for your situation.
Off-grid isn’t “panels plus pulling the plug”. It’s a system that lets your whole house run on its own — and that calls for the right changeover and protection, done properly to the standard.
What we do for you
We size the system to your usage, choose the right inverter and battery, fit the changeover and protection unit and register everything legally with Industria. That way your house runs safely and independently on your own sun.
Request your free, no-obligation quote — and we’ll work out your off-grid system precisely for you.
