No grid line, no problem. A properly designed off-grid solar system delivers reliable, silent, maintenance-free power to farmhouses where the grid doesn't reach — or barely works.
Remote farmhouses in India typically face one of three power situations: no grid connection at all (common for properties 1+ km from the nearest LT line), an unreliable grid with 4–12 hours of daily power cuts (common in rural Karnataka, Maharashtra, Rajasthan), or a grid connection limited to agricultural supply — 3-phase power available only during pump hours (typically 4–6 hours/day, often at night).
The traditional alternative is a diesel generator (DG). A 5 kVA DG set costs ₹40,000–60,000 and consumes 1.2–1.5 litres of diesel per hour at 50% load. At ₹90/litre, that's ₹108–135/hour, or ₹25–35 per kWh — four to five times the grid tariff. Diesel must be transported to remote locations (additional cost and logistics). DGs need oil changes every 200–250 hours, air filter replacement, and eventual overhaul. They're loud (65–75 dB at 7 metres), produce exhaust fumes, and require manual starting.
| Parameter | Diesel Generator | Off-Grid Solar + Battery |
|---|---|---|
| Initial cost (5 kW system) | ₹50,000–70,000 | ₹4,50,000–6,50,000 |
| Fuel/energy cost per year | ₹1,50,000–2,50,000* | ₹0 |
| Maintenance per year | ₹15,000–25,000 | ₹2,000–5,000 |
| Replacement (over 10 years) | 1–2 DG replacements: ₹50,000–1,40,000 | None (panels: 25 yr, LFP battery: 10–15 yr) |
| Total 10-year cost | ₹18–32 lakh | ₹4.7–7 lakh |
| Noise | 65–75 dB | Silent |
| Exhaust/emissions | CO₂, particulates, NOx | Zero |
| Availability | When fuel is available | Every sunny day, automatic |
*Assumes 6–8 hours daily operation. Actual fuel costs depend on load factor and diesel price.
A weekend farmhouse and a lived-in farmstead have very different load profiles. Sizing starts with an honest load audit:
| Appliance | Watts | Daily Hours | Daily Wh |
|---|---|---|---|
| LED lights (10 nos.) | 100 | 6 | 600 |
| Ceiling fans (4 nos.) | 280 | 12 | 3,360 |
| Refrigerator (inverter-type) | 80 (avg) | 24 | 1,920 |
| Water pump (0.5 HP) | 370 | 1 | 370 |
| TV (LED 43") | 60 | 4 | 240 |
| Mobile/laptop charging | 50 | 3 | 150 |
| Mixer/grinder | 750 | 0.3 | 225 |
| WiFi router | 12 | 24 | 288 |
| Total | — | — | ~7,150 Wh |
Add a 20% system loss margin (battery charging/discharging, inverter efficiency, cable losses): ~8.6 kWh/day effective requirement.
Air conditioning is the biggest variable. A 1.5-ton inverter AC draws 800–1,200 W and runs 8–14 hours in summer. A single AC adds 6,400–16,800 Wh/day — potentially doubling the system size. If AC is needed, the system design changes fundamentally: 6–10 kWp solar array, 20–30 kWh battery, and a 5 kW inverter minimum.
Water heaters (geysers) draw 1.5–3 kW and should be avoided in off-grid systems. Solar water heaters (evacuated tube type, ₹15,000–25,000 installed) are the correct solution — they're more efficient than using PV electricity to heat water.
Submersible pumps (1–3 HP) for borewell water draw 750–2,250 W. Run them during peak solar hours (10 AM – 2 PM) when panel output is highest, drawing directly from the panels without cycling through batteries. This extends battery life and reduces required battery capacity.
| Component | Specification | Rationale |
|---|---|---|
| Solar Array | 3 kWp (6 × 540 W TOPCon panels) | Produces ~15 kWh/day in Bangalore (5 PSH). Provides 80% margin over 8.6 kWh requirement for cloudy days and future load growth. |
| Battery Bank | 15 kWh LFP (48V, 300 Ah) | 1.75 days of autonomy at 8.6 kWh/day. Covers one full cloudy day without solar input. |
| Inverter | 3 kW pure sine wave | Handles peak running load (~1.7 kW) with headroom for motor starting surges (pump, mixer). |
| Charge Controller | Distributed MPPT (one per panel pair or per panel) | Handles partial shading from trees — common on farmhouse sites. |
Autonomy is the number of days the system can run on battery alone with zero solar input. For a farmhouse:
More autonomy means more battery — and more cost. The sweet spot for most farmhouses is 1.5–2 days: enough to ride through a cloudy day without running out, not so much that you're paying for battery capacity that sits unused 95% of the time.
Farmhouses often have trees, sheds, and uneven terrain that create partial shading across the panel array. String inverters lose 15–40% of total output when even one panel in a string is shaded. Alloy Charge's SunXtractor distributed MPPT controllers track each panel (or panel pair) independently — a shaded panel under a mango tree doesn't drag down the six unshaded panels on the cowshed roof. On a typical farmhouse with scattered panel placement, distributed MPPT harvests 15–25% more energy than string architecture over the course of a year.
Farmhouses rarely have a single large south-facing roof. Panels are typically distributed across multiple structures: the main house roof, a cowshed or storage building, a ground-mounted frame in an open area, or a carport/shade structure. Distributed MPPT controllers handle this naturally — each group of panels operates at its own optimal point regardless of orientation, tilt, or shading conditions.
Rural locations are more exposed to lightning than urban areas. Proper earthing is critical: a dedicated earth pit for the solar system (separate from the building earth), lightning arrestors on the array frame and at the charge controller input, and surge protection devices (SPDs) on both DC and AC sides. The earth pit should achieve ≤5 Ω resistance — difficult in rocky or sandy soil and may require chemical earthing (bentonite + charcoal backfill).
Farmhouse solar installations face threats that urban systems don't: rodents chewing DC cables (use conduit or armoured cable for all outdoor runs), monkeys walking on panels (panels are rated for 5,400 Pa snow load and can handle primate weight, but scratched glass reduces output over time), birds nesting under panel frames (install mesh skirts around panel edges), and dust/pollen accumulation (monthly cleaning schedule, or self-cleaning nano-coated glass at ~10% cost premium).
Agricultural water pumping is the largest single load on most farmhouses. Two approaches:
Solar-direct pumping: A variable-frequency drive (VFD) controller runs the pump directly from the solar array. No battery involved. The pump starts when solar irradiance crosses a threshold (typically 400–500 W/m²) and speeds up as irradiance increases. Flow rate varies with sun intensity. Cost-effective for irrigation where timing doesn't matter — the tank fills whenever the sun shines. Typical setup: 3–5 kWp dedicated solar array + VFD controller + submersible pump. No battery wear, no inverter losses.
Battery-powered pumping: The pump runs from the battery bank at fixed speed, on demand. Necessary when pumping must happen at specific times (livestock watering schedules, drip irrigation timed to avoid evaporation). Draws heavily from the battery — a 1 HP pump running for 2 hours uses ~1.5 kWh, which is 10% of a 15 kWh battery bank. Schedule pump runs during solar hours when the panels can directly power the pump and charge the battery simultaneously.
We design off-grid solar systems for remote properties — sized for your actual loads, your site conditions, and your autonomy needs. No grid line required.
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