When extreme heat hits, most of us know the drill – bring the pets inside, lower the blinds and, if you can, crank up the air-con. But while we’re focused on keeping ourselves and our four-legged family members cool, modern-day tech such as that electric vehicle (EV) parked in your drive or the home battery you’ve had installed to store energy generated by your solar panels will be taking the heat too.
The issue? This kind of equipment is typically powered by a lithium-ion battery1,2 – and not only have these batteries been recognised as the fastest-growing fire risk by Fire and Rescue New South Wales – generally speaking, exposure to high heat may increase the risk of a battery catching fire.3
So with the current El Niño climate cycle forecast to be record-breaking,4 what steps could – or should – you take to keep your rechargeable tech safe when the mercury soars? Should you avoid charging your EV in extremely hot weather? What are the warning signs that a lithium-ion battery might be overheating? And will a home battery keep the lights on during a blackout triggered by an Australian heatwave?
We’ll go into all of this and more to help you safely manage your battery tech in the modern electrified home.
How does extreme heat impact lithium-ion batteries?
As a general rule, when a lithium-ion battery is exposed to high temperatures, there’s a risk of triggering a chain reaction called thermal runaway.5
Thermal runaway begins when the battery gets too hot and can’t cool down fast enough. This heat causes even more heat to be produced, which can lead to a fire or explosion.6
As a result, the Queensland Fire Department suggests not storing lithium-ion batteries – and devices powered by lithium-ion batteries – in locations where they might be exposed to heat.7
In reality though, how a lithium-ion battery is impacted by extreme temperatures can depend on the individual type of battery.
How does extreme heat affect EV batteries?
When exposed to temperatures exceeding 40°C, EV batteries technically risk experiencing accelerated degradation. This can happen if extreme temperatures cause battery systems to overheat, which may damage cells and reduce the battery’s lifespan.8
However, Bjorn Siem, Senior Policy Manager at Australia’s Electric Vehicle Council, explains that newer EVs have advanced battery management systems that help keep the battery within optimal operating temperatures.
“In extreme heat, these systems may need to work harder to keep the battery cool, which may result in slightly lower range and potentially slower charging rates,” says Bjorn.
Could extreme heat cause an EV fire?
“An Australian heatwave, by itself, can’t trigger thermal runaway in a normally operating EV,” says Bjorn.
In line with that, according to the Australian Government, not only are EV battery fires rare, but of the 14 that EV FireSafe recorded in Australia between 2021 and April 2026, none were due to extreme air temperatures triggering thermal runaway.9
“Thermal runaway occurs when a battery cell begins heating uncontrollably, generally following an internal short circuit or serious thermal, electrical or mechanical damage, such as after a collision – or when exposed to an external fire,” says Bjorn.
“It’s important to note that EVs also have multiple layers of protection against thermal runaway. These include temperature sensors, battery-management software, active cooling, electrical isolation and the ability to restrict or stop charging.”
What can you do to look after your EV battery in high temperatures?
“EV owners generally don’t need to actively manage battery temperature themselves, as the vehicle is designed to do this automatically,” says Bjorn.
“However, a few habits can reduce unnecessary heat and energy use.”
You might like to:
- Park in the shade – Or use a sunshade to help keep cabin temperatures down, given hot interiors may make your EV’s battery work harder.10
- Pre-condition the cabin while plugged in – “This allows the car to draw energy from the grid, rather than the battery, to reach a comfortable temperature,” says Bjorn. “Most EVs have an app that enables drivers to turn on the air-conditioning remotely.”
- Keep your EV’s software updated – Manufacturers release software updates regularly, some of which are designed to improve those thermal management systems that help to cool battery cells.10
- Stick to charging guidelines – “The main risk to battery degradation over time is prolonged periods of sitting at 100% or 0%,” says Bjorn. “So follow the manufacturer’s guidance on daily charge limits, especially in hot conditions.”
Is charging an EV in hot weather safe?
“An EV can generally be charged safely in hot weather, provided the charging equipment is compliant, correctly installed, undamaged and is being used in line with the manufacturer’s operating guidelines,” says Bjorn.
“EVs continuously monitor battery temperature during charging. If the battery becomes too warm, they can activate cooling, reduce the charging rate or pause charging.”
That said, Bjorn adds that it may be preferable to charge overnight or during cooler parts of the day: “This reduces the amount of energy needed and may provide access to cheaper, off-peak electricity.”
How does extreme heat affect home solar system batteries?
In extreme heat over 40°C, the battery’s in-built management system may decrease charging or discharging rates to help prevent the battery cells from overheating.11
If the battery does start to get too hot, it may even temporarily stop working altogether, to help prevent thermal runaway from occurring.11
Because home batteries operate over a limited range of temperatures, considering where yours is positioned in your home is important12 – and there are specific rules that govern exactly where a battery can and can’t be installed.1 For example, where possible batteries should be installed away from habitable rooms, ideally in a utility area such as a garage (protected by a bollard), or outside.13
What happens to a solar panel’s output during hot weather?
The efficiency of solar panels decreases as the temperature increases.14 For each additional 3–4°C increase in temperature above 25°C, a solar panel’s power output decreases by about 1%.15
This means that on a very hot day, a solar panel can be 20% less efficient – or generate 20% less energy to be used or stored in a home battery – than on a cooler day.14
Having panels installed so they’re exposed to cool air at both the front and back for ventilation may help to mitigate the impact of extreme heat.15 And more efficient and premium solar panel systems typically suffer less performance loss due to temperature.15
Do solar batteries work in a blackout?
They can, provided the battery is configured to do this – and not all battery systems are.1
A solar battery with blackout protection will typically work in one of two ways depending on its set-up:1
- Some batteries can supply electricity to run appliances during a blackout – but once the battery is discharged, there’s no more electricity until the power comes back on.
- Other batteries can not only supply electricity to run appliances, but the solar panels they’re connected to can continue to charge the battery when it’s sunny.1
The second solar battery blackout protection set-up option is more expensive, but it may provide electricity over multiple days – during an extended blackout, for example – if it’s managed carefully.1
Load shedding, hot batteries and blackouts: how to handle compounding heatwave risks
While very hot weather may impact the operation of home batteries,11 high demand for electricity during a heatwave may also put extra pressure on the electricity grid.16
If there isn’t enough electricity to meet demand, the Australian Energy Market Operator may, as a last resort, instruct local energy distributors to manually switch off power to sections of the grid.17
This is known as load shedding – or rolling blackouts – where power is turned off in different areas for short periods, often without warning, to help protect the electricity network from long-term damage and widespread consumer outages.16,17
There are things you can do to help navigate these compounding heatwave risks.
To help keep the electricity grid stable during peak demand periods, including between late afternoon and early evening,18 the CSIRO suggests taking small actions to reduce your power consumption, such as:19
- Keeping your air-conditioning temperature at 24–25°C
- Closing the curtains and blinds
- Turning appliances off at the switch.19
You could also consider giving non-essential activities, such as using pool pumps, washing machines, dryers and dishwashers or even charging your EV, a rest during peak demand periods.18
If a blackout occurs and you have a home battery equipped with solar battery blackout protection, it’s important to be conscious of your energy usage to maximise the life of your stored power and accommodate any lags in battery discharge speeds that can occur in extreme temperatures.11, 20
To conserve your battery’s energy you could:20
- Identify essential appliances to keep switched on – These may include your fridge, modem, a few lights and even an air-conditioning unit.
- Switch off non-essential appliances – Turn them off at the wall so they’re not draining your battery’s energy reserves by drawing any standby power.20
To help keep your battery well ventilated in hot weather, it’s also important to check that its air intakes and fans aren’t blocked by leaves, cobwebs, debris or other items.11,13
Hot-weather habits for e-bikes and power tools
Understanding how to safely store and charge lithium-ion battery-powered e-bikes and cordless power tools may help to prevent a battery fire from igniting.
These strategies, such as only using the charger supplied with the device and not leaving batteries or devices unattended while being charged,21 can be useful all year round, but some habits may become particularly important in hot weather. These include:
Choosing storage spots wisely – Try to avoid storing lithium-ion-powered tools and light electric vehicles (LEVs), or their batteries, in areas where they can be exposed to direct sunlight or heat, keeping in mind that during a heatwave, some traditional storage spots may require a rethink due to rising temperatures.21,22
Avoiding charging in the heat – Victoria’s Country Fire Authority suggests only charging in moderate temperatures, and while larger batteries and equipment such as power tools and LEVs are often charged in a garage, shed or carport, these spaces may turn into ‘hotboxes’ during extreme weather.23
Not recharging too soon – Try to always let LEV and power tool batteries cool down after use and before recharging, a process which may take longer when air temperatures are extremely high.7
What are the warning signs a battery may be a fire risk?
Thermal runaway warning signs include:6
- Heat – A rapid rise in the temperature of the battery
- Appearance – The battery might blister, bulge, swell or become discoloured
- Noise – Popping, hissing, whistling and crackling sounds
- Odour – The battery may release pungent odours or electrolyte
- Vapour or smoke – Production of vapour, smoke and/or fumes.6
The South Australian Country Fire Service (SACFS) says it’s important to check your lithium-ion batteries and devices regularly for any signs of swelling, leaks, dents, discolouration or unusual heat.6
If you spot anything unusual, the SACFS says you should stop using the battery immediately and prepare for its safe disposal.6
What to do if a lithium-ion battery fire breaks out
The action you take can depend on the size of the device or battery that’s smoking or on fire.24
For example, for small batteries and devices such as phones or tablets, Western Australia’s Department of Fire and Emergency Services suggests extinguishing the device by:24
- Dousing it with water
- Dropping it into a clean bucket of water
- Using a nearby fire blanket or fire extinguisher if you’re trained in how to use them – these may help stop the fire spreading but are unlikely to entirely extinguish a lithium-ion battery fire.24
For larger batteries or devices such as power tools, e-bikes or other LEVs, the department suggests evacuating the area and closing any doors if it’s safe to do so to slow the spread of the fire, before calling Triple Zero and waiting in a safe location for firefighters to arrive.24
If any incident occurs involving an EV, Fire and Rescue NSW suggests:25
- Acting quickly to make sure the parking brake is engaged and the vehicle is switched off, before evacuating all passengers
- Staying at least 30 metres clear of the vehicle, and warning passers-by to do the same, even if there’s no visible smoke, vapours or flames
- Calling Triple Zero, taking care to inform the operator that the vehicle involved is an EV
- Making sure that remote keys can’t inadvertently start the vehicle.25
For more expert tips to help you plan for severe weather, visit our you.prepared emergency content hub.
The content in this article has been prepared based on current government and emergency services guidelines and expert advice provided at the time of publishing. This information is subject to change. Please be sure to check for the latest information and always consider your personal circumstances regarding home safety preparedness and response.
Where you have increased your Youi insurance cover or reduced your excess within 72 hours (or other period noted on your policy schedule) of a flood, storm, hail or bushfire occurring, cover will be limited to the amount that was effective prior to the change. Loss, damage or legal liability caused by, resulting or arising from flood, storm, hail or bushfire during the first 72 hours (or other period noted on your policy schedule) of your policy first being purchased is excluded unless certain conditions are met. Refer to the relevant Product Disclosure Statement for full T&Cs.
1. Source: Australian Government Department of Climate Change, Energy, the Environment and Water – Batteries, n.d.
2. Source: Australian Government Department of Climate Change, Energy, the Environment and Water – Electric vehicle batteries and motors, n.d.
3. Source: Fire and Rescue NSW – Battery and charging safety, n.d.
4. Source: Climate Council – Climate Pollution and El Nino, September 2026
5. Source: NSW Government SafeWork – Lithium-ion batteries, n.d.
6. Source: SA Country Fire Service – Lithium-ion batteries, n.d.
7. Source: Qld Fire Department – Lithium-ion battery safety, September 2026
8. Source: Electric Vehicle Council – How Does Extreme Weather Affect EV Battery Performance?, n.d.
9. Source: Australian Government Department of Climate Change, Energy, the Environment and Water – Electric vehicle facts, n.d.
10. Source: EVIE – How to Look After Your EV Battery in Summer, October 2025
11. Source: Amber Electric – What happens to your solar or battery systems during extreme weather conditions, January 2026
12. Source: Australian Government Your Home – Batteries, 2026
13. Source: NSW Government NSW Climate and Energy Action – Guide to owning a battery, n.d.
14. Source: Energy Matters – Aussie Heat Wave: Can Solar Panels Get Too Hot?, December 2023
15. Source: Australian Government Your Home – Rooftop solar, 2026
16. Source: NSW Government NSW Climate and Energy Action – What is a power outage and what to do, December 2025
17. Source: Australian Energy Market Operator – Fact sheet: Load Shedding, November 2025
18. Source: NSW Government NSW Climate and Energy Action – Stay safe during hot weather while using less electricity, December 2025
19. Source: CSIRO – You’ve got the power! Keeping our electricity during a heatwave, January 2024
20. Source: Energy Australia – How to use solar during a power outage, n.d.
21. Source: Fire and Rescue NSW – E-bikes, e-scooters, and other light electric vehicles (LEV), n.d.
22. Source: NT WorkSafe – Power tool battery fires, October 2022
23. Source: Victoria Country Fire Authority – Battery and charging safety, September 2026
24. Source: Government of WA Department of Fire & Emergency Services – Lithium-ion Batteries, n.d.
25. Source: Fire and Rescue NSW – Electric vehicles, n.d.
