Can Solar Batteries Run Air Conditioning? What You Need to Know

Can solar batteries power high-demand appliances like air conditioning?

Australians chasing lower bills, fewer emissions, and blackout resilience often ask the same question: Will my solar battery run the air-con when I really need it? The short answer is yes, provided the battery, inverter, and solar array are all specified for the heavy, sporadic loads that cooling units create. Below, we explain how to hit that sweet spot without overspending, so you can stay comfortable through summer peaks and unexpected outages.

An air conditioner’s compressor is effectively a small motor, and motors hate being rushed. At start-up, they draw a surge (or “inrush”) current well above their running load. A modest 2 kW inverter split may momentarily spike toward 3–4 kW, while a ducted system can hit 9 kW or more. Once running, consumption stabilises—typically 0.5–1 kW for an efficient bedroom split or 3–5 kW for a whole-home ducted unit, depending on efficiency rating, thermostat setting, insulation, and that sweltering January humidity we know too well. Older fixed-speed units are worse; inverter-driven models “soft-start”, easing the surge and playing far nicer with battery inverters.

The three building blocks: battery, inverter, and solar array

Battery capacity. To run an air conditioner on a solar battery, multiply its hourly use by the number of hours you want cooling. Four hours at 2 kW equals 8 kWh. Add 20–30 % so the battery is never fully drained, and you’re at roughly 10 kWh usable. Popular all-rounders like the 13.5 kWh Tesla Powerwall 3, Sungrow’s stackable SBR modules, or Sigenergy’s SigenStor tower all sit comfortably in this range and can be expanded later.

Inverter power. Continuous output must beat the steady running load, while surge output must handle the compressor kick-off. An inverter rated 5 kW continuous with 10 kW surge covers most modern, energy-efficient split systems, plus household basics. Larger or older splits—and certainly ducted units—may need 8 kW continuous or multiple hybrid inverters working in parallel. In short, battery size for an air conditioner is useless if the inverter can’t get the unit started.

Solar generation. In sunny Perth, a 6.6 kW panel array might easily refill a 10 kWh battery after lunch; in Hobart, you may need closer to 8 kW to achieve the same winter recharge. Panels also bypass the battery and help run the air-con directly on bright afternoons.

Can your current system handle the load?

1. Find the data plate. It lists rated input power (kW) and sometimes Locked Rotor Amps, a clue to surge size.
2. Read the battery spec sheet. Continuous and peak discharge figures tell you what it can actually deliver. The Powerwall 3, for instance, supplies around 11 kW continuous (Tesla lists 11.04–11.5 kW, region-dependent)—plenty for a typical split plus normal household circuits.
3. Check the inverter. Hybrid and multimode models publish surge ratings; a 5 kVA unit that can only sustain 7 kVA for two seconds may still stall a large compressor.
   
4. Add everything else that’s on. Fridges, pool pumps, and induction cooktops all nibble away at the same power pool. If the numbers are tight, consider a load-shedding relay that pauses non-essential circuits the moment the compressor wakes up.

If any component falls short, an upgrade is cheaper now than fried electronics later.

Sizing a new system for reliable cooling

A CEC-accredited designer begins with an energy audit, looking at summer bills and your “comfort window” (e.g., 4 pm–10 pm). For many households aiming for solar-powered air conditioning in Australia, the sweet spot is:

• Battery: 10–14 kWh usable (one expandable stack).
• Inverter: ≥5 kW continuous / ≥8 kW surge—higher if your unit is large or lacks a soft-start.
• Panels: 6–10 kW, angled for summer afternoon harvest.

Homes in Darwin’s wet season or with a zoned ducted system may bump battery storage beyond 20 kWh and add a second hybrid inverter. Up-front, that looks expensive, but STCs, occasional state rebates, and time-of-use tariff savings shorten payback, especially when avoidance of diesel generator hire in cyclone season is factored in.

Brand snapshots: real-world solutions

• Sigenergy SigenStor. A “Swiss-army” tower combining a hybrid inverter, lithium-iron-phosphate modules from 5 kWh up to 48 kWh per tower by adding extra modules, plus an optional EV charger. A common residential configuration delivers 10 kW continuous / 15 kW surge, while premium models step up to 16 kW continuous and 21 kW peak for 10 s—plenty for battery backup for air conditioning and other heavy loads.
• Sungrow SBR batteries with SH-T series hybrids. Modules are 3.2 kWh each and stack from 9.6 kWh (three modules) up to 25.6 kWh per tower. Each module supports a 30 A discharge current, so larger stacks maintain high peak power. Pairing a stack with the three-phase SH15T hybrid inverter (15 kW nominal, up to 25.5 kVA for 10 s in backup mode) keeps even stubborn ducted units humming.
• Tesla Powerwall 3. Fixed 13.5 kWh capacity but an impressive ~11 kW continuous output and rapid-switch backup circuits, handy for households chasing whole-home resilience.

Products from these reputable brands are typically found on the Clean Energy Council’s approved lists, essential for most rebates and grid connections. When installed by accredited professionals, systems using these components are designed to meet the safety requirements of AS/ NZS 5139.

Practical tips for trouble-free operation

Keep the thermostat at 24–26°C, use ceiling fans to circulate cool air, and schedule pre-cooling while the sun is high. A CEC-accredited solar installer can integrate smart load control so the

battery reserves are protected: the air-con throttles or pauses if state-of-charge drops below, say, 20%. Improving air sealing and upgrading ceiling insulation to around R-5—well above the minimum in many zones—can cut cooling run-time by roughly 20 % or more, extending battery hours without extra tech.

When replacing an ageing split, choose a modern inverter-drive model with a published soft-start current. Even mid-priced units now offer Wi-Fi energy statistics, perfect for fine-tuning usage against your battery curve.

A battery isn’t only for all-night cooling

Even a mid-size battery that can’t run the air-con until dawn still delivers value. It lets you:

• Dodge peak tariffs. Run the compressor through the 4 pm–9 pm price spike using solar energy saved at noon.
• Ride out short blackouts. A two-hour outage during a heatwave becomes a non-event when the lounge stays at 25 °C.
• Protect food and devices. Fridges, lights, and modems tick along without a generator’s fumes or noise.

For many households, that blend of comfort and resilience justifies a 10 kWh system even if all-night cooling isn’t in scope.

Conclusion: Stay cool, cut carbon, gain independence

Solar batteries can power high-demand appliances like air conditioning—the trick is matching capacity, inverter grunt, and solar harvest to your exact cooling habits. Done right, you slash grid reliance, keep the family safe in outages, and reduce greenhouse emissions every sticky summer evening. Engage a qualified, CEC-accredited professional, insist on load modelling and reputable hardware, and you’ll enjoy reliable, solar-cooled comfort for the next decade and beyond.

Thinking about taking the plunge? Your Energy Answers connects you with vetted local experts who can design a system that keeps your cool running, rain, shine, or blackout.