Inverter battery maintenance: simple habits that add years

An inverter battery usually sits in a corner and is forgotten until a power cut. A little regular attention is the simplest way to get a longer life out of it. These habits apply mainly to flooded (tubular and flat plate) batteries; the last section covers sealed SMF batteries.

Check the water level regularly

Flooded batteries lose water during charging. Once a month, look at the electrolyte level and top up with distilled water only, to the level marked on the case. Never use tap water or add acid. Do not overfill, because the liquid expands when warm.

Keep the terminals clean and tight

White or green powder on the terminals is corrosion, and it wastes power as heat. With the inverter switched off, wipe the terminals with a dry cloth, tighten loose clamps and apply a thin layer of petroleum jelly. Loose connections are a common reason for poor backup that people blame on the battery.

Give it air

Batteries release hydrogen while charging. Keep the battery in a ventilated spot, away from flames, sparks and direct sun, and never inside a sealed cupboard. Wear gloves and eye protection when you handle it.

Do not overload the inverter

Running more load than the inverter and battery were sized for drains the battery faster and shortens its life. If you add appliances over time, revisit the numbers in our sizing guide.

Keep it charged

A battery left discharged for long periods deteriorates. If the power is on most of the day, the inverter will keep the battery topped up. If you are away for weeks, ask whoever looks after the house to keep the mains switched on to the inverter.

Replace batteries in step

When an inverter uses more than one battery, an old battery paired with a new one drags the new one down. Replace the whole set together where the system needs it.

What about SMF batteries?

Sealed SMF batteries need no topping up and must not be opened. Keep the terminals clean, keep them ventilated and cool, and avoid deep drains. If one stops holding charge, it needs testing rather than water.

If your battery is struggling, bring the details to us. We charge inverter batteries at the store, and you can read more on our battery charging service page.