Four fire engines and around 25 firefighters were called to a fire at a block of maisonettes on Woodbine Grove in Penge.
Part of a split-level six-roomed maisonette on the third and fourth floor of a four-storey block was damaged by the fire. A man and woman left the property before the Brigade arrived. They were treated on scene for smoke inhalation by London Ambulance Service crews.
The Brigade's Fire Investigators believe the fire was accidental and involved a laptop battery.
A London Fire Brigade spokesperson said: "It's important that you don't leave laptops or phones plugged in to charge after the charge cycle is complete and never charge them on your bed. Keep them on flat, hard surfaces.
"It's also vitally important to use the correct type of charger for your device. Using an incompatible charger runs the risk of over-charging, which can have explosive results and cause a fire which could destroy your home and put lives at risk too."
Firefighters top tips for charging devices
The Brigade was called at 1107 and the fire was under control by 1202. Fire crews from Beckenham, Woodside and West Norwood fire stations were at the scene.