Three fundamentally different ways to connect solar to your property. Each involves different components, different costs, and different trade-offs between savings and independence.
Solar panels connect to a grid-tied inverter that converts DC to AC synchronised with the grid's voltage, frequency, and phase. The solar output feeds your loads first; any surplus flows backward through your meter into the grid. When solar output is less than your load, the grid makes up the difference. There are no batteries.
Net metering (where available) credits you for exported energy at a rate set by your state electricity regulatory commission. In Karnataka (BESCOM), residential net metering allows 1:1 offset within a billing cycle — each unit exported cancels one unit consumed. The credits don't carry over indefinitely or convert to cash; exact rules vary by state and change frequently.
When the grid goes down, a grid-tied inverter must shut off within 2 seconds. This is a safety mandate, not a design choice. Utility linemen repairing downed wires must know the line is dead. If a grid-tied inverter continued pushing power into a "dead" grid, it would energise the lines and create a lethal electrocution hazard. This behaviour is called anti-islanding.
The consequence: an on-grid solar system produces zero watts during a grid outage. If your area has frequent or prolonged outages — common in rural India, semi-urban areas, and during monsoon — an on-grid system offers no backup whatsoever.
On-grid is the cheapest solar topology because there are no batteries (the most expensive component). A 5 kWp on-grid residential system in India costs roughly ₹2.5–4.0 lakh installed, depending on the inverter type and panel quality. Payback period: 3–5 years at current BESCOM tariff rates for residential consumers (₹5.50–8.15 per unit depending on consumption slab).
A self-contained power plant with no grid connection. Solar panels charge a battery bank through charge controllers. An inverter converts the battery's DC to 230 V AC for your loads. The system must be sized to cover your entire load — there is no grid to fall back on.
Sizing is critical: you need enough panel capacity to charge the batteries during available sunshine hours, enough battery capacity to carry loads through the night and cloudy periods, and enough inverter capacity to handle your peak load including motor startup surges.
Autonomy days: How many consecutive days of cloud/rain the battery bank can sustain the load without solar input. For a farmhouse in Karnataka, 2–3 days of autonomy covers monsoon periods. For a critical application (telecom tower, vaccine storage), 3–5 days may be required.
Surge handling: Refrigerator compressors, water pumps, and AC units draw 3–7× their running power for the first 100–500 ms at startup. The inverter must handle these surges without tripping. A 3 kW continuous inverter needs at least 6 kW surge capacity to reliably start a 1 HP pump.
Low-load efficiency: At night, a house may draw only 200–500 W (lights, phone chargers, WiFi router). Some inverters consume 30–60 W of standby power — that's 10–30% of the load wasted as heat. Look for inverters with standby consumption under 10 W or with sleep modes.
Off-grid costs more upfront because of batteries and charge controllers. A 5 kWp off-grid system with 10 kWh LFP storage costs approximately ₹5–8 lakh. However, if you're currently running a diesel generator at ₹25–40 per unit (fuel + maintenance), payback can be 2–4 years. If there is simply no grid connection available, off-grid is the only option short of a permanent generator.
A hybrid system combines grid connection with battery storage. The system prioritises solar: solar charges the battery and powers loads first. Surplus solar can export to the grid (if net metering is available). When solar is insufficient, the battery kicks in. When both solar and battery are depleted, the grid takes over. During a grid outage, the system switches to battery backup — unlike on-grid, you keep power.
Most hybrid inverters follow a programmable priority stack:
This priority can be adjusted. Some users prefer to maximise self-consumption (never export); others prefer to maximise export earnings. The optimal setting depends on your tariff structure and net metering policy.
Hybrid systems cost more than on-grid (because of batteries) but provide backup. A 5 kWp hybrid system with 5 kWh LFP storage costs approximately ₹4.5–7 lakh. The financial case depends on the value you place on backup power. If you currently run an inverter-battery setup for backup during outages and separately have grid electricity for daily use, a hybrid solar system replaces both — eliminating grid bills and backup equipment in one installation.
| Factor | On-Grid | Off-Grid | Hybrid |
|---|---|---|---|
| Grid connection | Required | None | Optional (recommended) |
| Battery | None | Required | Required |
| Backup during outage | None | Full | Battery capacity limited |
| Net metering | Yes | Not applicable | Yes (if grid connected) |
| Upfront cost (5 kWp) | ₹2.5–4 lakh | ₹5–8 lakh | ₹4.5–7 lakh |
| Grid independence | 0% | 100% | 50–90% (depends on battery + solar sizing) |
| Best for | Reliable grid, maximise savings | No grid, or unreliable grid | Savings + backup + future-proofing |
| Complexity | Low | Medium–High | Medium–High |
Alloy Charge systems are designed for off-grid and hybrid topologies. The SunXtractor (distributed MPPT charge controller), PowerVault (LFP battery), and FreedomVolt (pure sine wave inverter) form a complete off-grid power plant. For hybrid installations, the system integrates with grid supply through an automatic transfer switch, giving you solar priority with grid fallback — and full backup during outages.
The right topology depends on three questions:
We'll assess your grid reliability, load profile, and goals to recommend the right system configuration.
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