How to Select an Inverter for Your Needs

On-Grid, with Battery Backup

On-grid systems can be configured with a battery backup system. Battery backup systems carry the penalty of added expense and often decreased efficiency, so take a realistic look at your needs before choosing this option.

First, think back about how many times the utility power has been out in the last five years or so, and for how long. If you live in tornado or hurricane country, and power outages are frequent and longer in duration than a few hours or a day, seriously consider adding battery backup to your system. If you have critical loads in your home, for example medically necessary health equipment, or you have elderly or frail individuals living in the home and they couldn't withstand a power outage in extreme heat or cold conditions, then this is definitely the system for you. Or perhaps you have a home business that relies on being electrified continuously for you to stay profitable, or your area experiences many rolling blackouts that wreak havoc with your computer files being lost.

Most battery backup systems are configured to enable just one or two circuits that can keep your critical loads on for a period of several days to a week or more during a blackout. This type of system uses utility power when available, and only transfers the loads to the battery in case of an outage. Once the utility comes back online, the loads are transferred back to the utility, and the batteries are typically recharged from the grid with the inverter's battery charger.

The choice of inverter for this type of system is going to rely on the capacity of your power generating system -- either solar-electric or wind-electric -- and the amount of system operation and maintenance convenience you require, as well as ease of installation. Other major factors besides price to consider are warranty, service reliability and manufacturer reputation, along with inverter efficiency ratings.

Larger Systems

Several manufacturers offer high volume inverters or inverters that can be ganged up in multiples to run very large systems suitable for industrial applications. In addition, research has been put into creating mini-grid systems where a small community of off-grid homes can share electricity production and battery storage capacity with one another. Talk with your sales representative about this potential if this is something you would like to explore further.