BATTERY BACKUP · CEBU BROWNOUTS
Ordinary grid-tied solar switches off the moment the grid fails. A hybrid inverter, a LiFePO4 battery and a dedicated backup circuit keep the fridge, fans, lights and Wi-Fi on. Here’s how long a battery lasts, what it costs in pesos and how it’s wired.
Solar panels alone won’t keep the lights on. A grid-tied inverter must shut down when the grid fails. For backup you need a hybrid inverter, at least one battery and a backup (essential-load) circuit for the things that matter.
On our cautious basis one 5.12 kWh battery delivers about 3.69 kWh from a full charge: around 7 hours of a fridge, fans, lights, Wi-Fi and TV (about 0.5 kW), or 3½–4½ hours with a 1 HP inverter aircon added, which is why we recommend two batteries with an aircon. Each battery is a ₱52,000 line in our itemised estimate.
WHAT HAPPENS IN A BROWNOUT
Anti-islanding is a safety rule, not a fault. It stops solar from feeding a dead line while crews are repairing it.
It disconnects from the grid in an outage and keeps a separate backup (LOAD) output running from the battery and, by day, the panels. Every system in our calculator uses a Deye single-phase hybrid from 5 to 10 kW, so it is battery-ready from day one.
Each 5.12 kWh LiFePO4 module stores the energy your essentials use after dark. One covers a typical 1-hour rotation; modules are added in parallel for longer outages or an aircon.
Only circuits wired to the inverter’s LOAD port stay on. The fridge, lights, fans and Wi-Fi move to a small backup panel; the water heater and oven stay on the main panel.
Net metering doesn’t change any of this. Exports stop during an outage, just like everything else on the grid side. If you’re still deciding between a grid-tied, hybrid or off-grid design, our on-grid vs hybrid vs off-grid guide compares how each behaves day, night and in a brownout.
What would one battery run in your home? Pick your appliances and see the hours, the peak power and how many batteries we’d suggest.
Estimate my battery backupBACKUP SIMULATOR
Choose what must stay on, how many batteries and when the brownout starts. The estimate updates as you go, with no contact details needed.
How long will my battery last?
Estimates · typical watts · 5.12 kWh batteries7.9 hours on 1 battery at 465 W average. Peak 465 W: within the power limits.
Estimated backup, battery only
7.9hours
Brownout from 6:00 p.m. → lasts until about 1:55 a.m. the next day
10:00 p.m.4 h in · ≈1.8 kWh left
Power check
OKWithin limits. A 50 A battery module supplies about 2,560 W; the 5 kW inverter is rated 5,000 W. Motors (fridge, pump, aircon) draw extra for a moment at start-up. The hybrid allows about twice its rating for 10 seconds, but each 50 A module only about 5,120 W, so here the module caps start-ups at about 5,120 W.
Batteries we’d suggest for this load
No solar counted, so these hold for evening brownouts. Tap one to try it.
1 battery: ₱52,000 list price for the battery modules in our itemised estimate. The hybrid inverter, panels and installation are priced separately.
The calculator sizes panels and batteries from your bill, which usually means one battery. Your choice of 1 battery travels with your quote request; each extra battery is ₱52,000 in the itemised estimate.
Estimates, not guarantees. Assumes the batteries are fully charged when the brownout starts (for example after a sunny day). A battery that has already been powering your evening, or after a cloudy day, lasts proportionally less. Runtime uses 3.69 kWh delivered per 5.12 kWh battery (80% usable × 90% conversion) and typical appliance watts: check your nameplates. The fridge is counted as always running, so real runtimes are often a little longer. Power check: about 2.6 kW continuous per 50 A battery module and the inverter’s rated output; start-up surge is not modelled (each module allows about 5 kW for 10 seconds, the hybrid twice its rating). Daytime solar follows an average Cebu day (3.7 kWh per kWp, PVGIS).
Energy sets the hours. Runtime is the energy a battery delivers divided by your average draw. Fewer watts running means more hours.
Power sets what can run together. A rice-cooker cycle costs well under an hour, and a pump about a fifth of the runtime. Switched on with an aircon, they can exceed what one battery module supplies.
Timing changes everything. Switch to a daytime brownout: solar carries the afternoon and the battery is still near full at sunset.
CHOOSING WHAT TO BACK UP
Most backup designs cover a handful of circuits. Whole-house backup is possible, but the battery and inverter grow quickly.
Typical configurations (estimates). Your appliance list and our site assessment decide the final design.
Deye’s manual notes that aircons need 2–3 minutes before restarting. If power drops and returns quickly, a unit without a restart delay can trip the inverter on overload. Choose an aircon with a restart delay, or put it on its own backup circuit that can be switched off, so a quick outage-and-return doesn’t trip the inverter. Sizing panels for aircon use is covered in solar for air-conditioned homes.
A 50 A battery module supplies about 2.6 kW continuously (50 A at 51.2 V), and the inverter has its own rating. Motors draw extra for a moment at start-up. The hybrid allows about twice its rating for 10 seconds, but each module only about 5 kW for 10 seconds, so with one module the battery sets the limit; with two, the battery and a 5 kW hybrid are about level. Two modules give an aircon room to start.
Ready for a price? The calculator sizes a solar + backup system from your monthly bill and lists every line, including the batteries.
Price my backup systemINSTALLATION
One extra panel board, a few circuits moved, and a switchover you mostly won’t notice.
Brownout: the inverter senses the outage and opens its grid relay (anti-islanding), then feeds the backup panel from the battery in milliseconds. By day, solar helps and keeps charging the battery. The main panel stays dark until the grid returns.
We walk the house with you and decide which breakers move. Usually that’s the fridge, lighting, fans and a few outlets for Wi-Fi, TV and laptops, plus one aircon if you choose.
A small essential-load board is fed from the hybrid inverter’s LOAD port. The chosen circuits are re-wired to it and labelled, so everyone knows what stays on.
We set up the inverter and battery, then switch off the main supply to check that the backup panel stays on. The hybrid switches the backup circuit to the battery in milliseconds, so lights and fans usually carry on. No transfer time is published, so anything that must never blink gets a small UPS.
Inverter and battery go somewhere shaded and ventilated, because the inverter reduces output above 45 °C. They also go above flood level, not in a ground-floor garage that floods. Our typhoon-ready installation guide covers mounting and protection for storm season.
No transfer time is published for the switchover. Put the modem/router, a desktop PC or network storage on a small UPS if they must never blink. Laptops ride through on their own batteries.
Panels refill the battery each day the sun shows. For long cloudy spells, a generator can feed the hybrid’s GEN port. Solar battery vs generator compares the running costs.
A grid-tied inverter can’t run a backup circuit. Adding storage usually means a hybrid inverter or AC coupling; see adding a battery to existing solar.
TIMING MATTERS
Cebu’s 2026 red-alert windows mostly fell in the late afternoon and evening, as solar output fades. That makes the battery, not the panels, your backup.
One home, three kinds of outage
01 / 03Chapter 01
1:00 P.M. · RED ALERT
In a daytime brownout the hybrid runs the backup circuit straight from the panels and puts any surplus into the battery. On an average Cebu day, our estimate is that a 4–5 kWp array can cover a typical essentials load until late afternoon, with the battery still near full.
Battery near full by sunset on a clear day
Chapter 02
6:00 P.M. · ROTATION
After about 5 p.m. there is little solar left, so the battery runs the backup circuit. On our cautious basis that is about 7 hours of essentials per fully charged battery, far more than a 1-hour rotation, and 3½–4½ hours if a 1 HP aircon is running.
One battery covers a typical 1-hour rotation
Chapter 03
DAY 3 · STILL NO GRID
Typhoon outages can last days. A battery won’t run a whole house that long, but the panels refill it each day the sun shows. Trim the backup list, and for long cloudy spells a generator on the inverter’s GEN port fills the gap.
Plan for days, not hours
At your pace. Select any chapter.
Want the full picture of how a solar home runs from morning to night? Walk through how solar works, step by step.
CEBU, 2025–2026
Dated facts from news reports and the grid operator. They describe what happened, not tomorrow’s schedule for your street.
123Grid alerts, 1 Jan–3 Sep 202693 yellow and 30 red on the Visayas grid (NGCP, via Daily Tribune)
≈1 hPer rotation, per areaVisayan Electric rotations, May and Aug 2026 (BusinessMirror, SunStar)
3–9 hRed-alert windowsMostly late afternoon and evening, May–Sep 2026 (BusinessMirror, Philstar, Daily Tribune)
30 minNotice before load droppingNGCP to the utilities, not to households (SunStar, 19 May 2026)
Five days on, about 7.4% of Visayan Electric customers were still without power; 92.57% had been restored by 9 November.
Source: SunStar, 9 Nov 2025Visayan Electric cut power in roughly one-hour rotations during red alerts. On 15 May the alert ran from 5 to 9 p.m.
Sources: BusinessMirror, 15 May 2026; SunStar, 14 May 2026From 3 to 8 p.m., with 2,123 MW available against a 2,418 MW peak.
Source: Philstar, 12 Aug 2026A red alert from 1 to 10 p.m. By then the grid had logged 93 yellow and 30 red alerts since January.
Source: Daily Tribune, 3 Sep 2026Reporting from a Cebu energy summit, SunStar wrote that the Visayas will likely keep facing supply shortages through 2027. Energy Secretary Garin said the solution is coming but late: “it will be a 2028.”
Source: SunStar, 12 Oct 2026Utility-specific notes on rates, service areas and backup:
WHAT IT COSTS
Straight from the itemised estimate behind our calculator, at list price before any promotion. Sizing uses VECO’s ₱14.89/kWh (Sep 2026).
₱52,000Per 5.12 kWh batteryLiFePO4 module, a separate line in the estimate
14–27%Added by one batteryBattery module only, on 5–10 kWp systems (43% on our smallest example). The backup option below also adds panels.
₱104,000Two batteriesOur pick when an aircon is on backup
3.69 kWhDelivered per battery80% usable × 90% conversion (cautious)
| Monthly bill | Solar only (battery-ready) | Solar + backup | Difference | Backup system |
|---|---|---|---|---|
| ₱4,000 a month | ₱119,800 | ₱171,800 | +₱52,000+43% · incl. ₱52,000 for the battery | 4 × 620 W panels, 5 kW hybrid, 1 battery2.48 kWp |
| ₱7,000 a month | ₱138,500 | ₱209,200 | +₱70,700+51% · incl. ₱52,000 for the battery | 6 × 620 W panels, 5 kW hybrid, 1 battery3.72 kWp, 1 more panel than solar only |
| ₱10,000 a month | ₱175,900 | ₱270,300 | +₱94,400+54% · incl. ₱52,000 for the battery | 9 × 620 W panels, 6 kW hybrid, 1 battery5.58 kWp, 2 more panels than solar only |
| ₱15,000 a month | ₱270,700 | ₱412,100 | +₱141,400+52% · incl. ₱104,000 for the batteries | 13 × 620 W panels, 8 kW hybrid, 2 batteries8.06 kWp, 2 more panels than solar only |
The backup option sizes more solar so the battery can refill (up to 2 more panels in these examples), and may step up the inverter, which is why the difference can exceed the batteries’ price: in these examples it adds 43–54% to the battery-ready price. Estimates only: the final design and price follow a site assessment. The essential-load board and circuit re-wiring are confirmed in your proposal after the site assessment, as are VAT treatment and warranty terms.
Comparing ready-made configurations? Our solar packages lay out starter, backup and larger systems side by side. Wondering whether a generator is cheaper for the same brownouts? Solar battery vs generator compares fuel, upkeep and noise.
Your own bill, your own number. See the itemised price of a solar + backup system for your home in about 30 seconds.
Calculate my backup system priceSTRAIGHT ANSWERS
What Cebu homeowners ask before adding a battery: runtime, aircons, cost and typhoon outages.
Already have solar? Read adding a battery to existing solar. Planning for storm season? See typhoon-ready installation. Or browse all solar guides for Cebu.
Not on their own. A grid-tied inverter must switch off when the grid fails. This is called anti-islanding, and it protects line workers repairing the lines. Panels help in a brownout only through a hybrid inverter with a battery, and only for the circuits wired to its backup (LOAD) output. By day the panels run those circuits and refill the battery; after dark the battery carries them. A battery-ready system without a battery goes dark like any grid-tied system.
Net metering does not change this: exports stop in an outage like everything else on the grid side. Every system in our calculator uses a Deye hybrid inverter, so a battery can be included from day one or added later.
In our itemised estimate each 5.12 kWh LiFePO4 battery is ₱52,000 (list price, before any promotion). On a 5–10 kWp system one battery adds roughly 14–27% to the price; on smaller systems the share is higher.
Choosing "Save + backup" in our calculator also sizes a little more solar so the battery can recharge. For a home with a ₱7,000 monthly bill that adds about ₱70,700 to a ₱138,500 battery-ready system, roughly 51% more. Installation and configuration are part of the estimate; VAT treatment and warranty terms are confirmed in your proposal.
For a typical 1-hour rotation, one 5.12 kWh battery is plenty for the essentials. On our cautious basis it delivers about 3.69 kWh from a full charge, roughly 7 hours of a fridge, fans, lights, Wi-Fi and TV drawing about 0.5 kW. A battery that has already powered your evening lasts proportionally less. Two batteries cover a full night of essentials, and we recommend two whenever an aircon is on the backup circuit.
Try your own appliance list in the simulator on this page. The results are estimates based on typical watts, so check your appliances' nameplates.
Yes, within limits. A 1 HP inverter aircon is rated at about 770 W but averages roughly 400–600 W through a night. Together with the essentials that is about 0.8–1.0 kW, or about 3½–4½ hours per fully charged battery. Power matters as well as energy: a 50 A battery module supplies about 2.6 kW continuously, which leaves little headroom for start-ups, so we recommend two batteries with an aircon.
Aircons need 2–3 minutes before restarting after power drops. Choose an aircon with a restart delay, or put it on its own backup circuit that can be switched off, so a quick outage-and-return doesn't trip the inverter.
Only if the system is designed for it. A typical backup design covers the essential circuits: the fridge, lights, fans, Wi-Fi and a few outlets, sometimes with one bedroom aircon. Water heaters, ovens, induction cookers and the other aircons stay on the main panel, which goes dark in a brownout.
Whole-house backup is possible with a larger hybrid inverter and four or more batteries, but heavy loads still have to stay within the inverter's rating, and the price rises quickly.
The hybrid switches the backup circuit to the battery in milliseconds, so lights and fans usually carry on. No transfer time is published, so put the modem/router, a desktop PC or network storage on a small UPS if they must never blink. Laptops ride through on their own batteries.
Typhoon outages can last days. Five days after Typhoon Tino in November 2025, about 7% of Visayan Electric customers still had no power, and after Odette in December 2021 Carcar was still without power at least 8 days after landfall. A battery alone won't carry a house for days.
With solar, the battery refills on every day the sun shows, so keep the backup list to the essentials and use the evening hours carefully. For long cloudy spells a generator still makes sense, and the hybrid's GEN port can accept one. Our battery vs generator guide compares the costs.
Yes. Every system in our calculator uses a Deye hybrid inverter, so it is battery-ready: you can start with panels only and add 5.12 kWh batteries when your budget allows. Under the ERC net-metering rules, a modification to a net-metered system goes through the utility's application process again, so plan for that paperwork.
If you already have solar with an ordinary grid-tied inverter, our guide to adding a battery to existing solar explains the options.
THREE WAYS TO MOVE FORWARD
Price a backup system in the calculator, request a quote built around your appliance list, or ask a question first. No obligation either way.
Your system, installed price and savings in about 30 seconds. No contact details needed.
Start the calculatorRoute BShare a few details and we’ll prepare a proposal after a site assessment.
Request my quoteRoute CHave a question first? Ask it here and get a straight answer.
Ask a questionROUTE A · INSTANT ESTIMATE
The same calculator and prices as the rest of the site. Your estimate stays on your screen unless you ask us to contact you.
Your promo code takes 10% off your system estimate, up to ₱50,000.
Choose your usual monthly bill. An estimate is all you need.
Using VECO at ₱14.89/kWh · Sep 2026. You can change your provider later.
About 30 seconds · No obligation
ROUTES B & C · TALK TO US
Every quotation follows a site assessment of your roof, wiring and priorities, so the price you approve is the price of the system you get.
Tell us what must stay on. We’ll design the backup circuit and size the batteries after a site assessment.
Not ready for a quote? Ask about battery backup for brownouts and we’ll reply by phone or email.
Reviewed 16 October 2026 · Runtimes and appliance watts are estimates
Anti-islanding (IEC 62116), 2× rated power for 10 s off-grid, battery current, 60 Hz support. Accessed 16 Oct 2026.
8 kW and 10 kW hybrids: off-grid peak, IP65, derating above 45 °C. Accessed 16 Oct 2026.
GRID, LOAD and GEN ports; backup delay setting (no guaranteed transfer time); aircons need 2–3 minutes to restart. Accessed 16 Oct 2026.
5.12 kWh module: 80% recommended depth of discharge, 50 A maximum (about 2.6 kW), 100 A for 10 seconds (about 5.1 kW). Used as our cautious runtime and power basis until the exact module is confirmed. Accessed 16 Oct 2026.
Grid-tied solar shuts off during outages unless designed for backup. Accessed 16 Oct 2026.
About one hour per area; red alert 5–9 p.m. on 15 May.
Rotations from 5:45 p.m. on 13 May in parts of Cebu City, Mandaue, Naga and San Fernando.
NGCP gives utilities about 30 minutes’ warning before manual load dropping.
Red alert 3–8 p.m.; 2,123 MW available against a 2,418 MW peak.
Red alert 5–10 p.m.; Visayan Electric one-hour rotations across Metro Cebu.
93 yellow and 30 red alerts, 1 Jan–3 Sep 2026 (NGCP); red alert 1–10 p.m. on 3 Sep.
92.57% of customers restored by 9 Nov 2025 after Typhoon Tino.
Carcar still without power on 24 Dec, after the 16 Dec landfall.
Reporter’s summary: shortages likely through 2027. Energy Secretary Garin, verbatim: “it will be a 2028”.
Rated inputs 770 W (1 HP) and 1,030 W (1.5 HP). Night averages of 400–600 W and 500–800 W are our estimates from the DOE label method.
1,367 (roof-flush) to 1,420 kWh per kWp a year. Our calculator uses a cautious 1,350, about 3.7 kWh per kWp per day, also used here for daytime recharge.
Systems may net-meter with or without storage; modifications go through the application process again (§12).
Electrical plans must be signed and sealed by a Professional Electrical Engineer.
The cost examples use VECO’s ₱14.89/kWh residential rate (Sep 2026) from our monthly-updated rate table.
BEFORE THE NEXT RED ALERT
Send us your appliance list and bill. We’ll design the backup circuit, size the batteries and give you an itemised price after a site assessment.
YOUR NEXT QUESTION
Each guide answers one question properly, with the numbers and sources behind it.