Solar for load shedding: sizing a system that actually works

Size from your load, not your house

Sizing starts with a list: which appliances must keep running during an outage, what each draws, and for how many hours. Fridges, borehole pumps and geysers dominate almost every domestic load, and a system sized without accounting for the pump will disappoint the first time the tank empties.

An installer who quotes before asking that question is selling a package rather than solving your problem.

• List the appliances that must stay on, with wattage and hours
• Decide explicitly whether the geyser is on backup or not — it changes everything
• Account for the borehole pump's starting surge, not just its running draw

Where quotes hide the cost

Panels are the visible part and the cheapest to compare. Batteries are usually the largest single cost and the first component quietly substituted for something cheaper. Mounting, cabling, protection and labour are where a quote becomes genuinely different from its competitor.

Ask for the inverter and battery specification in writing, by model. A quote that names the panels precisely and the battery vaguely is telling you where the compromise is.

After installation

Establish what the warranty covers and who honours it — the installer or the manufacturer — and whether the installer returns for servicing or only for sales. Batteries degrade; an installer with no service relationship is a problem deferred, not avoided.

Common questions

Hybrid or fully off-grid?

Hybrid keeps a grid connection and charges batteries when power is available, which lowers the battery capacity you need and therefore the cost. Fully off-grid costs more up front and is unaffected by extended outages.

Can I add to the system later?

Often, but only if the inverter was specified with headroom. Say at the quoting stage that you intend to expand, and get the answer in writing.