This guide is for households that need backup power and want to compare battery size, price, life and safety.
Grid solar and backup are different jobs
A standard on-grid inverter switches off during a power cut. This anti-islanding protection helps keep utility workers safe. Solar panels on the roof do not mean your home stays powered in an outage.
If cuts are rare, an on-grid system is usually the simpler financial choice. If you need fans, lights, internet, a fridge or medical equipment during cuts, compare a hybrid inverter and battery. Existing home inverters can sometimes remain separate from the solar system.
Size the essential-load circuit
Add the watts of appliances that must run together, then multiply by backup hours. A 100 W fan, 15 W light, 15 W router and 150 W average fridge load total about 280 W. Four hours needs 1.12 kWh before conversion losses and reserve capacity.
Air conditioners, geysers, pumps and induction cooktops can make a backup system much larger. Ask for both continuous and surge ratings.
Plan for ₹20,000 to ₹30,000 per usable kWh
As a broad 2026 planning range, a residential lithium battery package can cost about ₹1.0 to ₹1.5 lakh for 5 kWh before changes to the inverter or wiring. Quotes vary by chemistry, usable depth of discharge, power rating, enclosure, brand and warranty.
Compare warranted years and warranted energy throughput. A ten-year label with strict cycle or usage limits is not an unlimited promise. Ask what capacity remains at the end of warranty.
Give the battery a safe, serviceable place
Follow the manufacturer’s temperature, ventilation and clearance rules. Keep the unit away from living-room escape paths, direct sun, rain and flood risk. Use compatible protection devices and a trained installer. Do not mix unmatched batteries or alter a battery management system.
PM Surya Ghar assistance is calculated from eligible solar module capacity. Adding a battery does not raise the central subsidy. Read the scheme guide before choosing a hybrid design.
Lithium and lead-acid batteries suit different budgets
| Feature | Lithium iron phosphate | Lead-acid |
|---|---|---|
| Usable depth | Usually allows a larger usable share | Often needs a shallower discharge for longer life |
| Space and weight | More compact and lighter for the same usable energy | Larger and heavier |
| Upfront price | Higher | Lower |
| Maintenance | Battery management system controls operation | Some types need ventilation and regular care |
| Useful fit | Frequent cycling and compact home backup | Lower-budget backup where space and upkeep are manageable |
Lithium iron phosphate, often shortened to LFP, is common in new home storage offers because it combines useful cycle life with thermal stability. The chemistry name does not remove risk. The enclosure, cells, battery management system, wiring and installer still matter.
Do not mix battery ages, capacities or chemistries unless the manufacturer has approved the arrangement. A replacement battery must match the inverter and communication system.
Estimate backup from watts and hours
List only the appliances that must run during a cut. Add their running power, allow for motor starting power, then multiply by hours. Divide by inverter efficiency and the planned usable battery share. This gives a more realistic energy need.
| Example load | Approximate running power | Energy for 4 hours |
|---|---|---|
| 3 fans, 4 LED lights and router | About 300 W | About 1.2 kWh before losses |
| Above load plus refrigerator | About 450 W average | About 1.8 kWh before losses |
| One 1.5 ton efficient AC | Often 1,000 to 1,800 W while running | About 4 to 7.2 kWh before cycling and losses |
Actual appliance labels and behaviour matter more than this illustration. Refrigerators and pumps have starting surges. An inverter can fail to start a motor even when the battery holds enough energy.
A 3 kW solar array does not require a 3 kWh battery. Solar kW describes generation power. Battery kWh describes stored energy. Choose each from its own job.
Check how storage connects to the system
A hybrid inverter manages solar, battery and grid power in one system when all parts are compatible. An AC-coupled battery has its own battery inverter and can sometimes be added to an existing on-grid plant. Each route has different losses, controls and backup behaviour.
Ask what happens during a grid cut. Some systems power only a separate essential-load board. Some have a whole-home output but cannot run every appliance at once. Others do not provide backup even though a battery is present because the operating mode or wiring does not support islanded supply.
Also ask whether solar can recharge the battery during a long outage. The answer depends on the inverter design, minimum battery state, available sunlight and backup loads.
Compare usable energy, power and warranty together
- Nominal and usable capacity in kWh
- Continuous output and short surge power in kW
- Permitted depth of discharge and operating temperature
- Round-trip efficiency and standby use
- Warranted years, cycles, energy throughput and retained capacity
- Indoor or outdoor rating, flood risk and required clearances
- Inverter compatibility and communication protocol
- Local service, replacement terms and safe end-of-life route
A 10 kWh label does not mean every 10 kWh is available each day. Reserve settings, conversion losses, temperature and warranty limits reduce usable energy. Ask the vendor to show the usable figure used in the backup calculation.
Storage can be valuable where cuts disrupt work, water supply or medical equipment. It is not automatically the cheapest way to reduce a bill. Compare its backup value separately from the solar payback calculation.
Common questions
Will solar run during a power cut without a battery?
A normal on-grid system will not. Some hybrid or backup-capable designs can supply selected loads, but the system must be designed for that use.
How large a battery does a 3 kW solar system need?
There is no fixed match. Size the battery from essential appliance load and required backup hours, not only from panel capacity.
Which battery is best for a solar system in India?
LFP lithium batteries suit many homes that cycle storage often, while lead-acid can lower the upfront price. The right choice depends on usable energy, power, space, temperature, maintenance and warranty.
What is the solar battery price for a home?
A solar array does not set battery size. As a broad planning range, a 5 kWh residential lithium package can cost about ₹1.0 to ₹1.5 lakh before inverter or wiring changes. Compare current written quotes because chemistry, power rating and warranty change the price.
How much does a 3 kW solar battery cost?
A 3 kW array does not tell you how much storage you need. If you want about 5 kWh of usable lithium backup, a broad planning range is ₹1.0 to ₹1.5 lakh before any hybrid inverter, wiring or backup-board changes. Size the battery from the appliances and hours you need.
Can a battery run an air conditioner?
Yes, if the inverter can handle running and starting power and the battery has enough usable energy. AC use can drain a small battery quickly, so use the actual appliance input and required hours.
Can I add a battery after installing on-grid solar?
Often yes, but not always through the existing inverter. You may need an AC-coupled battery or a new hybrid inverter. Check warranty and DISCOM rules before changing the system.
Does a solar battery need maintenance?
It needs monitoring, safe temperature, clear ventilation or spacing, and periodic professional checks. Lead-acid types can need more routine care than sealed lithium systems.
How much energy does a 200 Ah solar battery store?
Amp-hours alone are incomplete. A 12 V, 200 Ah battery stores 2.4 kWh in theory because volts multiplied by amp-hours gives watt-hours. The usable amount is lower after discharge limits and conversion losses.
Official sources
Rules and portal processes can change. Check these sources before committing money.
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