A standard grid-tied solar system switches off during a power cut — that's a safety rule, so it doesn't send power into lines that engineers may be repairing. If you want your lights and fans to keep running during outages, you need a hybrid system: solar panels plus a battery and a hybrid inverter. But is the extra cost worth it?
When a battery is worth it
- You have frequent or long power cuts.
- You run loads that can't stop: a home office, medical equipment, a clinic, a shop's billing counter, cold storage.
- You're replacing a diesel generator or an old inverter-battery setup anyway.
- Net metering isn't available to you, or you get very little for exported power — storing your own solar is then worth more.
When it usually isn't
- Your grid supply is reliable and you have net metering. With net metering the grid works like a free battery — daytime surplus is credited against what you use at night.
- Your main goal is the fastest payback. Batteries add cost and wear out before panels do, so a plain grid-tied system pays back sooner.
PM Surya Ghar subsidy is calculated on the solar capacity (kW) you install. The battery itself isn't what the subsidy pays for, so budget for it separately.
Battery chemistries to know
| Chemistry | Typical life | Good to know |
|---|---|---|
| Lithium iron phosphate (LFP / LiFePO₄) | Several thousand cycles — often 3,000–6,000 | Today's default for home solar: safe, stable, no maintenance, lasts many years. |
| Lead-acid (tubular) | Roughly 500–1,200 cycles | Cheapest upfront, but heavier, needs water top-ups and is replaced more often. |
| Sodium-ion | Emerging | A promising lower-cost chemistry that's starting to appear; worth watching. |
Always compare the cycle rating at a stated depth of discharge, and the warranty in years — not just the price.
How to size the battery
- 1List your essential loads
Lights, fans, Wi-Fi router, fridge, TV — whatever must run during a cut.
- 2Add up their wattage
This is your running load, which sets the inverter size.
- 3Decide the backup hours
Load × hours gives the energy the battery must store (with some margin).
Our free Load Calculator does this for you — pick your appliances and backup hours and it recommends the inverter capacity (VA) and battery size (Ah).
Open the Load Calculator
