"If I have solar panels on my roof, why does my house go dark when the power cuts?"
It's one of the most common frustrations we hear from homeowners who've just installed or are considering on-grid solar. The panels are there, the sun is shining — yet the moment BESCOM cuts power, the inverter shuts down and you're in the dark.
This isn't a malfunction. It's deliberate design. Understanding why this happens — and what your actual options are — is essential before you invest in a solar system in Bangalore.
Why on-grid solar shuts down during power cuts: the anti-islanding safety rule
Every on-grid (grid-tied) solar inverter in the world is built with a feature called anti-islanding protection. When the BESCOM grid goes down — whether for scheduled maintenance, a fault, or load-shedding — your inverter detects the loss of grid voltage and frequency within 2 seconds and shuts itself down completely.
This is not a design flaw. It's a mandatory safety requirement.
Here's why it exists: when BESCOM cuts power to your street for maintenance, their line workers assume those cables are dead — no voltage, safe to touch and repair. If your inverter kept generating and feeding power back into the grid through your bi-directional meter, those supposedly "dead" wires would still be live. A lineman touching them would be electrocuted.
Anti-islanding protection ensures that when the grid goes down, your solar inverter stops contributing to the grid immediately — protecting utility workers, your neighbours' equipment, and the grid infrastructure itself.
This requirement is not unique to India. It's mandated under IEC 62116 (the international standard for anti-islanding) and enforced by every DISCOM in the country as a condition of grid connection. Your BESCOM SRTPV commissioning inspection specifically tests that your inverter's anti-islanding function is working correctly before your system is approved.
The result: on-grid solar = zero power during cuts
The practical implication is clear: a standard on-grid solar system provides no backup power during a BESCOM power cut, regardless of how bright the sun is shining.
Your 5 kWp system might be capable of generating 3 kW at that moment. It doesn't matter. The inverter is off. No power flows to your home.
This surprises many homeowners who assumed solar would give them some independence from BESCOM outages. It does not — unless you add either a battery or a hybrid inverter to your system.
Does this mean on-grid solar is a bad investment?
Absolutely not. The shutdown during power cuts is a feature you accept in exchange for the financial benefits of being on-grid:
Net metering earnings. Your solar system earns money from BESCOM for every unit it exports during normal operation. Over 25 years at Bangalore's tariffs, this is a significant income stream. Off-grid systems don't earn this.
No battery cost. By staying grid-tied, you avoid the ₹80,000–1,50,000 cost of a battery bank — and the replacement cost every 8–12 years.
Full PM Surya Ghar subsidy. The ₹78,000 subsidy is available for on-grid systems. Off-grid systems are excluded.
Lowest cost, fastest payback. Without batteries, a 5 kWp on-grid system can be installed for ₹2.5–3.2 lakh. The payback period is 4–6 years. Add batteries and you're at ₹3.7–4.8 lakh with a 6–8 year payback.
For Bangalore's urban core — where BESCOM supply is reliable and outages are measured in a few hours per month — on-grid solar is the right call for the vast majority of homeowners. You're optimising for financial return, not backup power independence.
How on-grid solar actually handles your electricity over a day
Here's what happens during a normal day with a functioning BESCOM grid:
7–8 am (early morning): Panels start generating as sunlight builds. Generation is low — perhaps 300–500 W. This powers lights and small appliances; the shortfall is drawn from BESCOM.
9 am–12 pm (morning generation builds): Solar output climbs steadily. By 10 am, a 5 kWp system is typically generating 2.5–3.5 kW. If your home load is 1–1.5 kW (AC off, normal daytime appliances), the surplus 1.5–2 kW is exported to BESCOM. Your bi-directional meter is spinning in the export direction.
12 pm–3 pm (peak generation): Maximum solar output — typically 3.5–4.5 kW for a 5 kWp system. If you run an AC now, your solar covers it entirely. Surplus still exports.
3–6 pm (afternoon): Output begins declining as sun angle drops. A 1.5-ton AC still running might exceed solar output — the shortfall is drawn from BESCOM.
6 pm onwards (evening/night): Panels produce nothing. Your home runs entirely from BESCOM. But your exported surplus from the day has already been credited to your account — reducing or eliminating what you owe.
Monthly settlement: BESCOM calculates the net of your total import vs total export for the month. If you exported more than you imported (common in summer for well-sized systems), BESCOM credits or pays you. If you imported more, you pay only the net difference at the applicable tariff.
Net result across a full year: A well-sized 5 kWp system for a 300–350 unit/month home typically results in zero to minimal annual BESCOM bills, with credits accumulating during high-generation months offsetting monsoon and heavy night-use months.
What happens when the grid comes back on after a cut
When BESCOM restores power, your inverter automatically detects the return of grid voltage and frequency. It performs a short synchronisation check (typically 20–60 seconds) and then reconnects to the grid and resumes normal generation. No manual intervention required.
If your inverter does not automatically restart after grid restoration, check:
- The inverter's display for any fault codes
- That the AC isolator switch is in the ON position
- The inverter's manual for the specific error message
Most inverters auto-restart within 1 minute of grid restoration under normal conditions.
What if you want power during cuts? Your three options
Option 1: Add a hybrid inverter + battery
This is the cleanest solution. Replace (or supplement) your on-grid inverter with a hybrid inverter that has an EPS (Emergency Power Supply) output — a dedicated backup circuit that stays live even when the grid is down.
When grid power fails:
1. The hybrid inverter disconnects from the grid (anti-islanding compliance)
2. It switches your selected backup circuits to battery power in milliseconds
3. Solar panels continue charging the battery during the outage
4. When the grid returns, the inverter reconnects to the grid automatically
What you can run depends on battery capacity:
- 5 kWh battery: fans, lights, router, one TV, refrigerator — for 4–6 hours
- 10 kWh battery: all of the above plus one 1-ton AC — for 5–7 hours
- 20 kWh battery: full household load including two ACs — for 4–6 hours
Investment: A hybrid inverter upgrade + 10 kWh LiFePO4 battery adds approximately ₹1.4–2.2 lakh to your system cost.
Option 2: Install a separate inverter-battery (UPS/home inverter)
A traditional home inverter (like Luminous, Su-Kam, or Exide systems) connected to a battery bank operates completely independently of your solar system. During a power cut, it automatically switches your home to battery power.
Your solar system and the home inverter run as two separate systems. The solar system generates during the day as normal, and the home inverter handles backup independently.
This approach is less elegant than a hybrid system, and you don't benefit from solar charging your backup battery during outages — but it's a lower-cost route to backup power if you already have solar or are adding solar later.
Investment: ₹15,000–40,000 for a quality home inverter + battery, depending on backup capacity required.
Option 3: Accept grid outages and optimise on-grid savings
For Bangalore homeowners in areas with rare outages (most of the city's urban zones), the honest recommendation is to skip backup entirely and maximise your on-grid solar ROI. The money saved by not installing batteries (₹1–2 lakh) invested elsewhere works harder than eliminating a few hours of outage per month.
This is the path most of our Bangalore residential customers choose.
How to tell which option is right for you
Answer these questions:
How many hours per day does your area experience BESCOM outages (on average)?
- Less than 30 minutes/day → On-grid only. Don't add batteries.
- 1–3 hours/day → Hybrid with 5–10 kWh battery makes sense.
- More than 4 hours/day → Hybrid with substantial battery, or evaluate whether a small standalone inverter-battery is more cost-effective.
Do you have critical loads that must not fail during cuts?
- Medical equipment (CPAP, dialysis)
- Home office servers or workstations
- Young children or elderly at home who need fans/AC
If yes, even in a low-outage area, a hybrid inverter with a modest battery is worth the investment.
What is your primary goal for solar?
- Lowest electricity bill and fastest payback → On-grid only
- Backup power during outages + electricity savings → Hybrid
- Complete grid independence → Off-grid (not recommended for urban Bangalore)
A note on "solar with inverter" combinations that don't work as expected
We frequently see homeowners who already have a traditional inverter-battery at home, install an on-grid solar system, and then discover that the two systems don't interact as they hoped — the solar doesn't charge the backup battery.
Standard on-grid solar systems are designed to feed the BESCOM grid, not to charge a home inverter battery. To integrate solar generation with your backup battery system, you need either a hybrid inverter or a specifically designed charge controller configuration. If you have an existing inverter-battery and want solar to charge it, tell your installer upfront — it changes the equipment selection entirely.
The bottom line
On-grid solar shutting down during power cuts is not a defect — it's a deliberate, globally mandated safety feature that protects utility workers and grid stability. For most Bangalore homes with reliable BESCOM supply, this is a minor trade-off for the significant financial benefits of net metering and the lowest possible system cost.
If backup power is a priority for you, a hybrid system solves the problem completely — at an additional cost that is justified when outages are frequent or critical loads need protecting.
Know what you're buying. A Sunvana Energy advisor will always tell you honestly what your on-grid system will and won't do, and recommend a hybrid upgrade only when the outage situation in your area genuinely warrants it.
Sunvana Energy installs both on-grid and hybrid solar systems across Bangalore and Karnataka. Contact us for an honest assessment of what system suits your area, consumption, and budget — no upselling.
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Anti-islanding requirements as per IEC 62116 and BESCOM SRTPV commissioning guidelines. Battery backup duration estimates are approximate and depend on actual load profile, battery state of charge, ambient temperature, and inverter efficiency. Always confirm backup requirements with your installer during the design stage.