London Fire Brigade (LFB) has been called to one e-scooter or e-bike fire every two days this year, an LFB spokesman said.
A lithium-ion battery fire can rip through a double bedroom in 10 to 15 seconds, Dominic Ellis, deputy commissioner at LFB, told City Hall on Wednesday.
The batteries, which power electric scooters and bicycles, can create "quick and ferocious" house fires, he explained.
A battery fire may start due to impact damage or short circuiting, the Fire, Resilience and Emergency Planning Committee heard.
Mr Ellis told the committee that there has been a 60% increase in e-bike fires this year, "partially linked to [retrofitted] bikes".
To date, there have been 70 e-bike, 14 e-scooter and 35 other lithium-battery fires in London in 2023, according to LFB data.
"For a lot of the gig economy... it’s at the end of their bed and they’re probably charging while [the owner sleeps] because they’ve just done a 14-hour shift and they need to get back out there again," Mr Ellis said.