Runtime depends on battery energy and connected load. Start with the appliances you need during the cut.
Hours = battery Ah × volts × usable fraction × efficiency ÷ load watts. Use your system's specifications.
A fan, LED lights and router draw less than the same setup plus a TV. Check appliance wattages.
Power the router and any fibre terminal. Backup electricity cannot guarantee your internet provider stays online.
150Ah × 12V × 0.50 usable × 0.85 efficiency ÷ 170W gives about 4.5 hours. Actual runtime varies.
Check water only in serviceable batteries as instructed. Use distilled water; never open sealed batteries. Ask a technician when unsure.
EchoRepel sells a 200W car inverter. Observe socket limits; never backfeed home wiring. Run engines outdoors only.