Two of the most common questions we hear from Kerala homeowners are "what happens at night?" and "what about the monsoon?". This guide answers both, with what actually happens to your power supply and your KSEB bill.
Do solar panels work at night?
No. Solar panels turn sunlight into electricity, so they stop producing after sunset. Moonlight and street lights are far too weak to make useful power. Output starts again at dawn, rises to its peak around midday, and falls in the evening.
That does not mean you are without solar savings at night. How you get power at night depends on the type of system:
| System | At night | In a daytime power cut |
|---|---|---|
| On-grid (most homes) | Your home draws from KSEB. Your daytime exports set it off on the bill through net metering. | Switches off for safety until KSEB power returns |
| Hybrid | Draws from the battery first, then from KSEB | Battery and panels keep essential loads running |
| Off-grid | Runs only from the battery | Runs from panels and battery; there is no KSEB supply |
See on-grid, hybrid or off-grid to choose between them.
How net metering covers your night-time use
In the day, a well-sized system makes more than your home uses, and the extra units go to KSEB through your net meter. At night, you take units back. KSEB bills you only for the difference: units taken minus units sent. So the sunshine of the day pays for the fans, lights and AC at night.
For a home using 400 units a month with a 3 kW system, that brings the two-monthly bill from about ₹7,516 to about ₹100, even though most of the AC use is at night. Our KSEB solar bill guide shows how it is worked out, and how many ACs a 3 kW system can run covers night-time cooling in detail.
Do solar panels work in rain and cloudy weather?
Yes, but less. Panels still produce from the daylight that comes through the clouds. On a light overcast day the output is noticeably lower than on a clear one; under heavy monsoon cloud and steady rain it can fall to a small fraction of a sunny day. Between showers, when the sun comes out, output jumps back quickly.
- Dry months (roughly December to May): the highest output of the year
- Southwest monsoon (June to September): the lowest, with long overcast spells
- Northeast monsoon (October and November): afternoon storms, with clear mornings on many days
Kerala's yearly average of about 133 units per kW a month, which we use to size systems, already includes these rainy months. A 3 kW system makes about 400 units a month on average: more than that in the dry months, less in the monsoon.
How Kerala homes get through the monsoon
With net metering, the units you export in the sunny months are banked and set off against the monsoon months when the panels make less. That is why you size a system on your average use over the year, not on the monsoon months. Our guide to sizing solar from your KSEB bill shows how.
Panels with good low-light performance help a little on cloudy days. For example, ReNew rates its bifacial panels for strong output in early morning, late evening and cloudy weather. See choosing solar panels for a Kerala home.
Does rain clean solar panels?
Mostly, yes. Kerala's monsoon washes off loose dust for months at a time. But rain does not remove everything: bird droppings, dried leaves and the dust film that builds up in the dry months can stay on, especially on low-tilt panels. Any of these on one part of a panel cuts its output.
- Clean the panels every few weeks in the dry months, and check them after the monsoon.
- Use plain water and a soft cloth or sponge, early in the morning or in the evening when the glass is cool.
- Avoid detergents, hard brushes and pressure washers, which can damage the coating.
- Do not walk on the panels, and use a safe ladder and roof access.
Are solar panels safe in heavy rain and storms?
Yes, when installed well. Panels are sealed and built to sit outdoors in rain for decades. What matters in a Kerala monsoon is the installation: a structure that stands up to strong winds, sealed and weatherproof junction and distribution boxes, proper earthing, and lightning protection. We use chemically anchored, hot-dip galvanized structures built to IIT/NIT certified designs, with earthing and lightning protection on every system.
Do you need a battery for nights and power cuts?
For saving on your bill, no. Net metering does the job of a battery for an on-grid system, at no extra cost. A battery is worth it only if power cuts are a problem where you live and you want fans, lights, the fridge and Wi-Fi to stay on. A hybrid system adds that backup; most homes need a 2 to 5 kWh battery for essential loads. Batteries carry 18% GST and get no subsidy.
Common questions
Do solar panels work at night?
No. They need daylight. With net metering, the units you export in the day are set off against what you use at night, so your bill still falls.
Do solar panels work on cloudy and rainy days?
Yes, at lower output. They produce from the daylight that comes through the clouds, and output rises quickly when the sun comes out.
How much less do panels make in the Kerala monsoon?
Monthly output is lowest from June to September. The yearly average of about 133 units per kW a month already includes these months, and net metering carries surplus units from sunny months to rainy ones.
Does an on-grid solar system work during a power cut?
No. For the safety of KSEB line workers, an on-grid inverter switches off when the grid goes down, even in the day. You need a hybrid system with a battery for backup.
Does rain clean solar panels?
It washes off loose dust, but not bird droppings, leaves or the dry-season film. Clean them gently with plain water every few weeks in the dry months.
Jasper Solar designs every system around Kerala's monsoon, from the structure to the panel choice. Book a free home visit to see what your roof can make through the year.
Er. Akhil S.TProject Engineer, Jasper Solar Solutions
Project engineer with 7 years in the solar field and more than 400 completed solar projects. Akhil designs and oversees rooftop installations for homes and businesses, from site survey to KSEB commissioning.
