The whole point of an inverter is that you barely notice load-shedding. So when it doesn't switch over and you're plunged into darkness anyway, it's frustrating — and usually fixable. Here are the common causes.
1. The battery
A flat, ageing or faulty battery is the most common reason an inverter won't carry the load. If it worked before and now drops out instantly, suspect the battery — especially if it's older lead-acid or has been deeply discharged repeatedly (see battery lifespan).
2. Settings / configuration
Inverters have modes and changeover settings. An incorrect configuration can stop it switching over cleanly when the grid drops. This is a quick fix for an installer who knows the unit.
3. Overload
If too much load is on the backup side — a geyser, kettle, heater or oven sneaking onto the inverter circuit — it trips to protect itself. Only essential loads should be on the inverter, and the system sized to them.
4. Wiring / installation
How the essential loads and changeover are wired matters. A poor installation can prevent clean switchover.
Get it diagnosed
We work out whether it's the battery, settings, an overload or the install — often it's a configuration or battery issue, not a dead inverter. See inverter installations or book a callout.