Is Solar Battery Storage Worth It in 2026?
How battery storage changes solar payback, what size to buy, and the household profiles where it pays for itself fastest.
Key takeaways
- Self-consumption typically rises from ~35% to 70%+ with a correctly sized battery.
- Time-of-use tariffs let you arbitrage cheap overnight electricity.
- Most homes are well served by 5–10 kWh of usable capacity.
- Check usable capacity, throughput warranty and cycle count, not just headline kWh.
What a battery actually changes
Without storage, midday surplus is exported for a low rate and bought back in the evening at a high one. A battery closes that gap. The value of each stored kWh is the difference between your import rate and your export rate — which is why batteries got far more attractive as that spread widened.
Sizing it correctly
Oversizing wastes capital; undersizing leaves savings on the table. Look at your evening and overnight consumption rather than your total annual usage. Homes with an EV or heat pump justify larger capacity because they have somewhere to put the stored energy.
What to compare between quotes
Usable capacity differs from nominal capacity. Compare warranty terms in cycles or total throughput (MWh), round-trip efficiency, whether backup power during outages is included, and whether the inverter is hybrid or AC-coupled to an existing array.
Frequently asked questions
Can I add a battery to existing solar panels?
Yes. An AC-coupled battery retrofits to almost any existing array without replacing your solar inverter.
Will a battery keep my lights on in a power cut?
Only if backup or EPS functionality is specified and wired in. It is an optional extra on most systems.