Shared Solar + Shared Battery = Energy Independence
Protostar FUSION
One shared rooftop solar system and one shared lithium battery bank, engineered to run every flat and office at full load, off-grid, through the day and into the night. The patented SPDU gives each home its own share, and hands over to the grid seamlessly only when that share is done.
30 yrs
performance warranty on panels
20 yrs
battery service life
~5 yrs
payback for homes, no subsidy
~3 yrs
payback for commercial establishments
One roof, one battery, one SPDU per flat
Watch how Fusion routes power through a full day. Each flat and office has its own SPDU: sun first, battery next, grid only at the very end.
The sun runs every home, and charges the battery
Panels feed each flat and office through its own SPDU, and the surplus charges the shared battery bank.
Five parts, engineered as one system
This is the exact architecture we install, in the order the power flows.
Shared solar system
Panels across the full terrace, engineered as one plant on a raised structure. The whole roof works for the whole building.
Shared battery bank
One central lithium (LFP) bank stores the day's surplus for the evening and night, at a fraction of the cost of a battery in every flat.
Off-grid first
Flats, offices and common areas run on solar and stored power before touching the grid. Lifts, pumps and lighting can join too.
SPDU technology
Each flat and office gets its own patented smart IoT device that manages that unit's allocation and consumption, metered and visible on the Nova app.
Seamless grid hand-over
Once a unit's allocation is exhausted, the SPDU transfers it to its own DISCOM connection without interruption, till the next day.
The regular way vs the Protostar way
Most families end up buying two half-solutions. Fusion is one whole one.
The regular way
- Buy solar, then still buy backup separately
- Grid-tied array stops the moment the power does
- Every flat keeps its own UPS on lead-acid batteries
- Batteries last 3 to 5 years, then a replacement bill
- Backs up only a few lights and fans
The Protostar way
- One system that does both, sized to your actual loads
- Whole building keeps running through a power cut
- One shared lithium bank instead of a UPS in every flat
- Batteries built for 20 years of service
- Powers everything in the flat or office, ACs included
And the surprise: for a typical 2 BHK, Fusion costs about the same as individual solar plus a basic UPS, while backing up the whole home instead of a few circuits.
Costs less, works better
The same physics and the same purchase, made in bulk and engineered once. That is why the shared system beats a rooftop full of individual ones.
Shared infrastructure
Panels, inverters and batteries installed as one large unified system for the whole building, lowering the cost per kW for everyone.
One battery bank
A single central lithium bank is far cheaper per unit of storage than dozens of individual batteries scattered across flats.
One hybrid inverter system
One engineered hybrid system replaces a UPS inverter in every flat, along with all their fans, trolleys and trailing wires.
One maintenance contract
One cleaning and service contract for the whole building instead of dozens of separate ones, each chased by its own flat.
One roof, no allocation disputes
Individual systems would each need their own marked-out patch of terrace, and the sunniest patches are finite. A shared system uses the whole roof as one plant.
Shade shared equally
Every panel belongs to everyone. Whatever a shaded panel loses and whatever the best panels gain is spread across all flats in proportion to their share.
Your terrace stays yours
A single elevated system is planned around a clear terrace deck, so the roof stays open for morning walks, evening gatherings and society celebrations. Dozens of scattered private systems would consume the whole terrace.
Fusion, next to everything else you could do
We cost every alternative in our proposals, side by side. Here is the honest picture, so your society can decide with open eyes.
| What matters | Protostar Fusionsolar + battery + SPDU | Shared grid-tiedsolar + SPDU, no battery | Individual solar + UPSper-flat systems |
|---|---|---|---|
| Keeps your home running in a power cut | Whole home, ACs included | Pauses with the grid | A few circuits on the UPS |
| Battery | Shared lithium bank, 20-year service life | None | Lead-acid, replaced every 3–5 years |
| Uses the whole roof as one plant | Marked-out patches, allocation disputes | ||
| Terrace stays usable for the society | One elevated structure, clear deck | Scattered systems consume it | |
| Maintenance | One contract for the building | One contract for the building | Every flat chases its own vendor |
| Needs a subsidy for the numbers to work | Pays back in ~5 years on its own | Usually leans on PM Surya Ghar |
Shared grid-tied solar is offered for residential societies in Maharashtra under the Grid Connected Micro-Grid framework. Every proposal we prepare shows all options costed side by side for your exact building.
Payback in about 3 years. Diesel bills at zero.
Daytime businesses are made for solar: you use power exactly when the sun produces it. Add the shared battery and the SPDU, and every office in the building gets its own metered, uninterrupted supply.
The DG set stays off
No diesel runs, no fumes, no fuel logistics. The battery bank carries the building through every outage, silently.
Offset expensive evening power
Stored sun power replaces the costliest grid hours, which is exactly why office paybacks land around 3 years.
Workstations and servers keep running
Clean, uninterrupted power for the equipment your business actually depends on. No reboots, no lost work.
Easy to finance. Warranted for decades.
Participation is flat by flat: each home contracts and pays for its own share, and can finance it in its own name.
Finance available
Each flat applies in its own name. Rate and sanction are at the lender's discretion.
Warranty at a glance
- 30-year performance and 12-year product warranty on the solar modules
- 10-year warranty on the lithium battery bank, with a 20-year rated service life
- 10-year warranty on the hybrid inverter and the mounting structure
- 5-year warranty on workmanship
Be ready before the next summer. Backed up before the next monsoon.
A free rooftop feasibility survey tells your building exactly how much solar and storage your roof can hold, and what every flat and office would save. No commitment, no charge.