1. Check the battery's thermal environment
Most home batteries are rated to operate up to 45°C ambient. Above that, the battery management system throttles output or refuses to discharge entirely. A battery in a sun-baked garage that hits 50°C in February will silently underperform.
Do this: Check the temperature where your battery is mounted on a 40°C day at 3pm. If the ambient is over 40°C, talk to your installer about adding ventilation, shade, or relocating to a cooler spot. Cost: usually $200–$500.
2. Verify the firmware is current
Tesla, Sungrow and BYD all push firmware updates that improve battery thermal management and DEBS optimisation. Out-of-date firmware can cost you 5–10% on summer performance.
Do this: Open the app, check firmware version, look up the latest version on the manufacturer's site. If it's behind, request an update through your installer (or trigger it via the app for Tesla).
3. Confirm aircon load doesn't exceed battery output
A modern reverse-cycle ducted aircon draws 4–7 kW continuously when working hard. If your battery's continuous output rating is 5 kW (typical for Sungrow/BYD setups), the battery can just cover the aircon - with no headroom for other loads. Big aircon households on smaller batteries end up pulling from grid during the hottest evenings.
Do this: Check your battery's continuous power output spec. If it's under 7 kW, you may want to programme your system to give priority to non-aircon circuits during heatwaves, and let the grid carry the aircon. Counter-intuitive but it protects the battery from thermal stress.
4. Schedule a pre-summer maintenance check
Some installers offer free 12-month maintenance checks. The check usually includes: cleaning of the inverter cooling fins, visual inspection of cabling and connections, firmware update, and a test discharge.
Do this: Email your installer in October. "Can you book me in for a pre-summer check?" Most will say yes, sometimes free, sometimes $150–$250. Worth it.
5. Set up Storm Watch / extreme weather modes
Tesla's Storm Watch automatically charges the battery to 100% before forecast severe weather (Bureau of Meteorology warnings). Sungrow and BYD have similar features in their apps. Most homeowners don't enable them by default.
Do this: In your battery app, find the "Extreme Weather", "Storm Mode" or "Backup Reserve" setting and enable it. During WA summer storm season (December–February), this ensures the battery is full when the grid is most likely to drop.
6. Review your tariff plan
Summer is when peak-window rates hit hardest under Synergy Smart Home Plan. If you've been on Home Plan A1 all year, summer is when switching to Smart Home Plan pays off most. Run the comparison through Synergy's My Account tool - most pool households and big-aircon households are better off on Smart Home Plan.
Do this: Log into Synergy My Account. Use the tariff comparison tool. Switch if it shows savings. Takes 5 minutes online.
Bonus: Insurance check
Most home and contents policies cover battery systems automatically, but some require explicit declaration if the install value exceeds a certain threshold (usually $20k). Summer storm season is the wrong time to discover you're underinsured.
Do this: Email your home insurance provider. "I have a home battery system installed worth $X - is this covered under my policy or do I need to declare it?"