In this guide
One of the first questions people ask us is whether they need batteries. The answer depends on how reliable your power is and what you want from solar. This guide compares the three main types of system, with examples for homes in Thane, Mumbai and Navi Mumbai.
On-grid solar: the simplest way to cut your bill
An on-grid (grid-tied) system is connected to the electricity grid. Your home uses solar power first and takes the rest from the grid. It has no batteries, so it costs less and needs less maintenance.
The catch is that an on-grid system usually shuts down when the grid goes off. This is a safety feature, so it is normal, but it means you will not have solar power during a power cut. Where your distributor allows it, extra solar power can be exported to the grid; rules and billing differ, so ask what applies to your connection.
Best when: power cuts are rare and your main goal is a lower bill. This suits many flats and bungalows in Thane, Mumbai and Navi Mumbai.
Off-grid solar: power without the grid
An off-grid system works on its own. Panels charge batteries, and the batteries supply your power. It is useful where there is no grid connection, such as a farmhouse or a remote plot, or where cuts are very frequent.
The trade-off is cost and care. Batteries are a significant part of the price, they wear out over time and the system must be sized carefully so you do not run out of power at night.
Best when: there is no grid, or the grid is very unreliable.
Hybrid solar: a lower bill and backup
A hybrid system is connected to the grid and also stores power in batteries. It lowers your bill like an on-grid system and keeps essential loads running during a cut, such as lights, fans, the router and a fridge.
It costs more than on-grid because of the batteries and the more advanced inverter, but it gives you the best of both.
Best when: you want savings and backup, for example for a home office, a clinic or a family member who depends on power at night.
Quick comparison
- Connected to the grid: on-grid yes, off-grid no, hybrid yes.
- Batteries: on-grid no, off-grid yes, hybrid yes.
- Power during a cut: on-grid usually no, off-grid yes, hybrid yes (for the loads you choose).
- Upfront cost: on-grid lowest, hybrid and off-grid higher.
How to decide
- Note how often and how long your power goes off in a year.
- List what must keep running during a cut. A small list needs a small battery.
- Check how much shade-free terrace space you have. A battery system still needs panels.
- Think about the future. If you may want backup later, ask about a hybrid-ready inverter now.
If your building has a lift, water pumps or common lighting, also read our guide to solar for housing societies.
Understanding batteries
If you choose hybrid or off-grid, the battery is the part that needs the most thought.
- Lead-acid batteries usually cost less to buy, but they need space and ventilation, may need regular maintenance and generally last fewer years.
- Lithium batteries usually cost more up front, take less space, and tend to last longer and need less upkeep.
To size a battery, list what must run during a cut and for how long. Add up the power of lights, fans, the router and a fridge, then multiply by the hours you want to cover. A short list needs a much smaller battery than full-home backup.
Will solar make my bill zero?
Not always. Even when solar covers most of your units, your bill can still include fixed charges, minimum charges and taxes set by your distributor. Ask your installer to explain which part of the bill solar can reduce.
Exporting extra power to the grid
On-grid and hybrid systems can often send surplus power to the grid, where your distributor allows it and a suitable meter is installed. The rules for billing and credit differ between distributors and consumer types, so ask what applies to your connection before you decide.
Common mistakes
- Buying batteries “just in case” when power cuts are rare.
- Choosing a system without checking shade and terrace space.
- Expecting an on-grid system to run during a power cut.
- Choosing only on the lowest quote without comparing scope and warranty.
Get advice for your site
The right choice depends on your building, your usage and your budget. Book a site visit and we will recommend a system after seeing your terrace, or read more about our on-grid, off-grid and hybrid solar systems.
Frequently asked questions
Does an on-grid solar system work during a power cut?
Usually not. A standard on-grid inverter switches off when the grid fails, as a safety measure for people repairing the lines. If you want power during cuts, you need a hybrid or off-grid system with batteries.
Can I add batteries to an on-grid system later?
Sometimes. It depends on the inverter. If you think you may want backup later, ask about a hybrid-ready inverter at the start.
Which type of solar system costs the least?
On-grid systems usually cost the least up front because they do not need batteries. Batteries add cost and eventually need replacing, so a hybrid or off-grid system costs more to buy and maintain.
Will solar reduce my electricity bill to zero?
Not always. Fixed charges, minimum charges and taxes can remain even if solar covers most of your units. Ask your installer which part of your bill solar can reduce.
How long do solar batteries last?
It depends on the battery type, how deeply it is used and how it is maintained. Lithium batteries generally last longer than lead-acid ones but cost more. Ask for the warranty in writing.