Home / Power Backup

IPS or inverter: How to plan home backup power

Labels are often used loosely. A better decision starts with your load, desired runtime, battery and appliance sensitivity.

In everyday conversation, “IPS” often means a complete home backup system, while “inverter” refers to the unit that converts battery DC into appliance-ready AC. Product naming varies, so compare the electrical specifications and output waveform instead of relying on the label.

Step 1: Make a realistic load list

Write down every device that must run during an outage and its wattage: lights, fans, router, television and anything else essential. Add simultaneous wattage, then leave sensible headroom. Appliances with motors can draw a higher starting surge than their normal running watts.

Step 2: Decide the runtime

A system designed for thirty minutes is very different from one designed for four hours. Battery capacity is commonly expressed in amp-hours, but nominal battery energy is not the same as usable AC energy. Voltage, safe depth of discharge, inverter efficiency, battery age and load all affect real runtime.

Step 3: Check the output waveform

Pure sine wave output closely resembles utility power and is generally the safer choice for sensitive electronics, motors and audio equipment. Modified wave products may cost less but can cause noise, extra heating or incompatibility in some devices. Follow each appliance manufacturer's power requirements.

Step 4: Choose battery chemistry and placement

Lead-acid batteries are common and may require ventilation and maintenance depending on type. Lithium options can offer deeper usable capacity and longer cycle life but require compatible charging and battery management. Keep batteries in a secure, ventilated location away from heat, moisture and children.

Installation and safety

Backup wiring should be handled by a qualified technician. Proper cable size, fusing, earthing, isolation and circuit selection matter. High-load equipment such as heaters, kettles and air conditioners should not be added unless the system was specifically designed for them.

Useful planning formula: essential watts × desired hours gives a rough watt-hour target. It is only a starting point; real systems need allowance for conversion loss, battery limits and surge loads.

Questions for the seller or installer

By the LM Electronics Blog editorial team · General educational guidance