Brownout backup: UPS, batteries, inverters and generators
Pag brownout, ano ang tatagal? Build the backup before you buy it: a DC UPS that keeps the router and Wi-Fi up, a battery and inverter for the store freezer, a hybrid that carries the aircon at night, and the grid-tie system that goes dark the moment the grid does. Every build shows the current, the hours left and the moment a part gives up.
Open the labFree, in your browser, no account needed. Part of a free electronics simulator with 293 parts, 193 lessons and 66 builds.
What you can do
- See how long a 12 V battery keeps a router, a freezer, lights or a fan running, in hours, from the battery’s real capacity.
- Learn which inverter a compressor can start, and why a bigger inverter needs a bigger battery BMS too.
- Find out why a grid-tie system gives nothing in a brownout, and what a hybrid or a changeover relay adds.
- Size the Home UPS builds on 12, 24 or 48 V LiFePO4 for your own loads.
Builds (11)
Router DC UPS
Keeps a 12 V router running through a power cut.
Sari-sari store freezer through a brownout: battery, inverter and hours
12 V 100 Ah LiFePO4 battery, 1000 W pure-sine inverter, a chest freezer and two LED bulbs. The panel shows the…
1 HP inverter aircon on a 3.6 kW hybrid at night: what the battery sees
Night-time: no sun, a 24 V 100 Ah LiFePO4 battery feeding a 3.6 kW hybrid, a 1 HP inverter aircon, a refrigerator and…
Why a 1.5 HP non-inverter aircon trips a 3 kW inverter at start-up
A 24 V LiFePO4 battery, a 3 kW pure-sine inverter and a 1.5 HP non-inverter aircon. Switch the aircon on and watch the…
Grid-tie solar in a brownout: why the lights go out even at noon
The grid, a kWh meter and main breaker, a 3 kW grid-tie inverter on four panels, and the house loads. Switch the grid…
Home UPS on a 24 V LiFePO4 battery: charger, inverter, changeover relays, two 220 V outputs
Keeps two 220 V circuits powered through outages from a 24 V LiFePO4 battery; charges from the grid when it returns.
Home UPS on 8 × 3.2 V LiFePO4 cells + BMS: charger, inverter, changeover relays, two 220 V outputs
Keeps two 220 V circuits powered through outages from 8 × 3.2 V LiFePO4 cells; charges from the grid when it returns.
Automatic emergency light
LED lamp turns on when mains fails, charges when it returns.
200 Ah power station on a 12.8 V LiFePO4 battery: 2 × 12 V, 3 × USB, mains charger
12.8 V 200 Ah (2560 Wh) power station on a drop-in battery, two fused 12 V outputs, three USB outputs, a watt meter…
200 Ah power station from four 3.2 V prismatic LiFePO4 cells: 4S BMS, 2 × 12 V, 3 × USB, mains charger
12.8 V 200 Ah (2560 Wh) power station from four prismatic cells with a 4S BMS, two fused 12 V outputs, three USB…
12 V low-voltage battery cutoff
Disconnects the load before the battery is damaged.
Questions answered
- Will my solar run the aircon at night?
- Why does my aircon trip the inverter when it starts?
- Does grid-tie solar work in a brownout?
- What keeps the Wi-Fi router up in a brownout?
Calculators
Battery runtime calculator
How long a battery runs a load
Solar panel and battery size calculator
Panel watts, battery size and controller current for a daily load
Breaker and wire size calculator (Philippines)
The breaker and the mm² THHN or PDX for an appliance or a circuit, by the Philippine Electrical Code
Also on the lab
Solar PV simulator · Battery and BMS simulator · ESP32 simulator · Arduino simulator · Breadboard simulator · House wiring simulator · PCB layout and perfboard · Piso Wi-Fi and vending machines on solar