Before you choose storage
- A standard on-grid inverter stops during a grid outage for anti-islanding safety. Backup needs a hybrid setup with isolation and a battery.
- LiFePO4 batteries are commonly rated for 3,000 to 6,000 cycles, or about 10 to 15 years in this comparison. Ray2Volt quotes a 10-year lithium-ion battery warranty.
- PM Surya Ghar assistance can reach ₹78,000 for an eligible 3 kW home plant. The battery itself is not covered.
- Storage is most useful when outages disrupt your home or business. Where supply is reliable, an on-grid plant usually pays back sooner.
A lower electricity bill does not automatically mean backup power. In a normal on-grid installation, the inverter disconnects when the DISCOM supply fails, even if the sun is shining. Tell the installer at the start if you need lights, fans or equipment to stay on during cuts.
That requirement leads to a hybrid inverter and battery. LiFePO4 packs are smaller and need less routine attention than tubular lead-acid banks. The comparison here uses a 10-year lithium warranty and round-trip efficiency above 90%, but the exact model specification belongs in your quotation.
Storage has a separate cost. It shifts solar units from one time to another; it does not add to the day's generation. Judge the extra investment against the outages you actually experience and the cost of your present backup arrangement.
Why on-grid panels stop in an outage
Panels produce DC electricity. A grid-tied string inverter changes it to AC and matches the DISCOM's voltage and frequency before supplying your premises and, where permitted, exporting surplus.
When grid supply fails, that inverter must stop feeding the connection. The safety function is called anti-islanding protection. It prevents an array from energising street wires while technicians may be repairing them.
A hybrid system uses a transfer arrangement to isolate your property from the grid and supply chosen circuits from the panels and battery. Some systems switch in under 20 milliseconds; confirm the actual transfer time and supported loads for the model quoted.
Compare lithium and lead-acid batteries
Tubular lead-acid batteries remain a lower upfront cost option for backup. Daily charging and deep discharging are harder on them, and owners must allow for watering and terminal care.
For this comparison, lithium iron phosphate, or LiFePO4, offers more usable energy from its rated capacity and thousands of charge cycles. Its chemistry has good thermal stability, though installation location and protection still matter in Andhra Pradesh's heat.
Ask the supplier to state these four items on the battery quote:
- Usable depth of discharge: Keep a lead-acid bank near a 50% discharge limit in this comparison. A LiFePO4 pack can provide about 85% to 90% usable capacity.
- Expected cycle life: The comparison uses 1,000 to 1,200 cycles, around 3 to 4 years, for tubular lead-acid and 3,000 to 6,000 cycles, around 10 to 15 years, for lithium. Actual life depends on use and temperature.
- Written warranty: Ray2Volt quotes a 10-year product warranty for lithium-ion batteries. The lead-acid example uses a 3-year prorated warranty; confirm the exact terms for any offered model.
- Routine care: Lead-acid needs water and terminal checks. Sealed, wall-mounted lithium packs avoid water topping but still need inspection of their enclosure and connections.
| What to compare | Tubular lead-acid battery | LiFePO4 battery |
|---|---|---|
| Usable depth of discharge | Up to 50% in this comparison | 85% to 90% usable |
| Cycles to 80% capacity | 1,000 to 1,200 cycles, about 3 to 4 years | 3,000 to 6,000 cycles, about 10 to 15 years |
| Round-trip efficiency | 75% to 80%; more energy is lost | 92% to 96% |
| Routine maintenance | Water topping and terminal checks | Sealed pack; no water topping |
| Space required | Heavy unit needing floor space | Compact wall-mounted unit |
| Typical warranty in this comparison | 3 to 4 years, often prorated | 10-year lithium-ion product warranty |
When storage is worth its extra cost
Separate the return from solar generation from the value of keeping power on. Typical on-grid payback after subsidy is 4 to 5 years for homes and 3 to 5 years for businesses, subject to a site audit. A business that loses service during a cut, such as a hotel or resort, may place a higher value on backup than a site that can pause work briefly.
Adding a battery raises the initial cost, while a 5 kW array still produces roughly 20 to 22.5 units a day on the annual average used here. Those units may be used immediately, stored with some losses, or exported according to the connection rules.
What the subsidy covers: For eligible homes under PM Surya Ghar, the stated amounts are ₹30,000 for 1 kW, ₹60,000 for 2 kW and up to ₹78,000 for a 3 kW system with the required DCR modules and registered vendor. The central assistance does not pay for the battery bank.
In the illustrative comparison, adding storage could extend payback to about 6 to 7 years. That is not a quote for your roof. Typical on-grid ranges are 4 to 5 years for homes after subsidy and 3 to 5 years for businesses, subject to a site audit. Also price the interruption you are trying to avoid:
- Generator fuel: The example estimates diesel generation at ₹28 to ₹38 per unit and lithium storage at roughly ₹6 to ₹8 per unit amortised over 10 years. Ask for the assumptions behind any site-specific comparison.
- Lost business during a cut: A two-hour interruption can stop a clinic, diagnostic lab, tuition centre or shop from serving customers. Record how often that occurs before paying for backup.
- Household use during cuts: In Tirupati and Chittoor, summer or monsoon interruptions may make quiet automatic backup valuable. Decide which appliances truly need to stay on.
Size the battery for essential circuits
Backing up central AC and water heating can require a large, expensive pack. Start with the smallest set of loads that must run through a typical outage, then check their starting surge and daily use.
Your electrician can separate those loads onto a dedicated backup sub-panel. In a home hybrid installation, non-essential appliances stop during a cut while the selected circuits receive battery and available solar power.
Work through the following example:
- List essential appliances: Lights, BLDC fans, Wi-Fi, TV and an inverter fridge total roughly 650 to 750 W in this example. Measure your own appliances rather than copying the figure.
- Choose backup hours: At a 0.75 kW load for four hours, usable energy needed is
0.75 kW × 4 hours = 3.0 kWh. - Allow for usable capacity and losses: At 85% depth of discharge and 92% efficiency, nominal battery size is
3.0 kWh ÷ (0.85 × 0.92) ≈ 3.83 kWh. - Pick a suitable pack: A 5.0 kWh modular lithium pack leaves headroom for roughly 4 to 5 hours of these essential loads, subject to the inverter and appliance start-up demand.
Plan for a later battery: If backup is a future need, ask Ray2Volt about a compatible hybrid-capable inverter when installing an on-grid solar plant. A suitable battery can then be added later without replacing that inverter, after confirming model compatibility.
Decide who needs hybrid backup
Base the choice on outage frequency, the cost of interrupted work and how much you can spend now.
Sites where hybrid storage can help
- Homes with regular cuts: If you lose power for more than 1 to 2 hours most days, automatic backup for selected loads can be useful. Check the timing and duration of recent cuts.
- Clinics and healthcare sites: Refrigeration and diagnostic equipment may need continuity. Review our solar options for healthcare and confirm each device's backup requirement.
- Offices and IT equipment: Servers and communications can restart or fail during brief interruptions. Include their actual load and any UPS requirement in the design.
Sites that may prefer on-grid solar
- Urban homes with reliable supply: With few outages, on-grid solar and net metering may give a better financial return. Typical home payback after subsidy is 4 to 5 years, depending on the audit.
- Homes focused on initial cost: An eligible homeowner can use PM Surya Ghar support for the PV plant and defer the separate battery expense.
- Day-shift factories: A plant that uses most solar units while operating may get strong value from commercial on-grid solar without storage. Assess downtime separately.
Install the battery safely and plan maintenance
A lithium battery's management system monitors voltage, temperature and current, and can disconnect the pack when it detects a fault. Ask what protection and alarms the quoted model provides.
Install the pack in a shaded, ventilated utility area. Ray2Volt specifies DC surge protection, suitable cables and earthing for the site, then arranges net-metering support and service. Our registered office is in Srikalahasti, with branches in Tirupati, Nagari and Puttur. Confirm service access and the manufacturer's temperature limits before choosing a location.
Check the assumptions: The costs, payback comparisons and scheme amounts here are indicative. Subsidy rules can change and eligibility depends on your project. Confirm the current scheme and get a site audit before relying on a figure. Ray2Volt does not provide tax or investment advice.
Questions about solar backup
Will ordinary on-grid solar run during a power cut?
No. Anti-islanding protection shuts a standard grid-tied inverter down when the grid fails. To power appliances through the outage, specify a hybrid inverter, battery, isolation arrangement and dedicated backup circuits.
Does PM Surya Ghar pay for a home battery?
No. Eligible residential rooftop PV may receive up to ₹78,000 for a 3 kW home system under PM Surya Ghar, but the battery is a separate customer expense. Confirm your current eligibility and vendor requirements.
How does LiFePO4 life compare with tubular lead-acid?
The comparison uses 3,000 to 6,000 cycles, or about 10 to 15 years of daily use, for LiFePO4, with a 10-year lithium-ion product warranty. Tubular lead-acid is shown at 1,000 to 1,200 cycles and about 3 to 4 years, with regular water topping. Actual life depends on use.
Can storage be fitted to my current on-grid plant?
Yes, but check the inverter first. A compatible hybrid-ready model can accept a suitable battery. With a standard string inverter, the options may be a replacement hybrid inverter or an AC-coupled battery system. Have the installer check electrical compatibility.
What battery size covers basic household appliances?
For lights, fans, Wi-Fi, a fridge and laptops drawing about 1.2 to 1.5 kW together, the example allows a 5 to 7.5 kWh lithium bank for about 3 to 5 hours. Measure your actual loads and starting surge before buying.
Ray2Volt Solar Private Limited
We design, install, and service rooftop solar for homes and businesses across Tirupati district and Andhra Pradesh, from PM Surya Ghar residential systems to commercial and industrial plants. Every enquiry starts with a free power audit.
Compare on-grid and hybrid options for your site
Tell Ray2Volt which appliances must run during a power cut. We will check your bills and roof, then quote an on-grid plant and a suitable backup option.
