Four fire engines and around 25 firefighters tackled a fire on Kenilworth Avenue in Wimbledon.
Part of a second-floor flat, located in a semi-detached house converted into flats, was damaged by fire. There were no reports of any injuries.
One of the Brigade's 32 metre turntable ladders was used as an observation tower during the incident.
The fire is believed to have been accidental and caused by a lithium battery pack.
A London Fire Brigade spokesperson said: “Lithium batteries store a significant amount of energy in a very small space and are much more powerful compared to other types of batteries. If that energy is released in an uncontrolled way, then a fire or explosion may result. If there is overheating, crushing, penetrating or overcharging, then a fault can occur within damaged battery cells which may cause the battery to catch fire and/or explode.
“Lithium batteries are susceptible to failure if incorrect chargers are used, so it’s important to always use the correct charger for the product and buy an official one from a reputable seller.
"You should also unplug your charger when you have finished using it and we would advise not to leave it unattended or charging while people are asleep.
“Try to ensure they are not getting knocked around while in use or while being carried as spares as this can increase the chance of damage to cells.”
The Brigade's 999 Control Officers received five calls about the fire.
The Brigade was called at 1200 and the incident was over for firefighters by 1449. Crews from Wimbledon, Wandsworth, Tooting and Mitcham fire stations attended the scene.