Home Inverter Batteries

Tubular batteries have positive plates made of lead-alloy spines inside fabric tubes, which resist shedding of active material during deep discharge and so give longer cycle life. Flat plate batteries have pasted grids, are cheaper and have shorter life under heavy cycling. For areas with long or daily power cuts, tubular is generally the better choice.

Check the inverter's DC voltage: 12 V needs one battery, 24 V needs two in series, 36 V three. For more backup time, add parallel strings of identical batteries only if the inverter manual allows it. The battery Ah and the load decide the backup time, so use the backup calculator before buying.

Flooded tubular batteries need distilled water added when the electrolyte level falls near the minimum mark. The interval depends on usage, charging voltage and temperature, and can range from a few weeks to a few months. Use only distilled water, check levels regularly, and never add acid. Follow the user manual for the model.

It is not advised. Starter batteries are built for short, high-current bursts and are damaged by repeated deep discharge, so their life in inverter service is short. Use deep-cycle batteries designed for inverter duty, either tubular or good flat-plate types, and match the capacity to the inverter.

Common causes are age, a partly charged battery because of short charging periods, sulphation, low electrolyte level, loose connections, or a load higher than assumed. Capacity also falls at higher discharge rates. Measure the actual load, check the charger output, and have a technician test each battery.