Home Inverter and Battery System for Lights, Fans and More

Where power cuts last for hours, a UPS is not enough. An inverter with a battery bank charges from the utility while it is available and supplies the lights, fans and other chosen loads when it fails.

This guide explains how the system works and how to size it.

Key takeaways

• An inverter and battery system supplies household loads for hours, not minutes.
• The battery size sets the backup time; the inverter size sets how many loads run at once.
• A pure sine wave inverter is gentler on appliances.
• Heavy loads such as air conditioners need a much larger system.

How it works

The inverter has a charger inside. While the utility is on, it passes the supply to the loads and charges the battery. When the utility fails, it switches to the battery in a fraction of a second and makes AC power from it. When the utility returns, it switches back and charges again.

Sizing the system

List what you want to run, add the watts, and choose an inverter with a rating comfortably above the total. Then multiply the watts by the hours you want to get the energy, and choose a battery bank with more rated capacity than that, because the usable share is smaller. The battery voltage must suit the inverter.

• Lights and fans use little power and run for hours on a modest battery.
• A refrigerator needs a high starting current for its motor.
• An air conditioner or a large pump needs a much larger inverter and battery.

Inverter or UPS?

A UPS protects sensitive equipment for a short time, an inverter system runs ordinary loads for long hours. Some homes use both: a small UPS for the computer and an inverter for the rest.

Battery choice and care

Tubular lead-acid batteries are common and cost less, while lithium batteries last longer and need less care but cost more at the start. In both cases the batteries need a cool, ventilated place, and lead-acid batteries need regular checks. For more, see battery replacement and service.

When to call us

Give us the list of what you want to run and for how long, and we will size the inverter and the batteries. Use the quote page, see our home UPS and backup solutions, or look at the inverters we supply.