Fire and Rescue NSW (FRNSW) has warned shoppers of the danger of Christmas gifts powered by lithium-ion batteries such as e-bikes, e-scooters, laptops or power tools, saying it has responded to 180 such fires since January, up from around 16 last year.

Both re-chargeable and disposable batteries should be treated with caution as they can expel molten flammable metal and emit toxic gases when on fire.

NSW Minister for Emergency Services Steph Cooke says most of these fires occur when lithium-ion batteries are in the process of charging and overheat, causing “an explosion of flames in living rooms or garages”.

“Just a few weeks ago an e-bike battery caught fire and almost burnt down a family home in Manly. A brick wall was the only barrier that prevented flames spreading from the garage to the remainder of the house,” she said.

FRNSW is warning people to not over-charge lithium-ion batteries or leave them charging overnight unattended, or on beds and sofas or highly flammable and insulating materials, to use approved charging equipment and not to charge batteries that show signs of damage.

It also urges that they be stored in a cool, dry area away from combustible materials, ideally outside of bedrooms and living spaces, and that they be properly disposed of.

When lithium-ion batteries fail, they are prone to ‘thermal runaway’, which sees them build up intense heat until they violently burst, causing toxic, flammable and explosive gases and flames that are extremely difficult to extinguish, FRNSW Acting Deputy Commissioner Strategic Capability Trent Curtin said.

"Firefighters often have to use copious amounts of water to ensure that they are extinguished and adequately cooled to prevent re-ignition,” Mr Curtin said.

“The main risk is caused by over-charging or trying to charge a damaged battery.”

Research is being conducted into policy and standards that help prevent injuries and damage.