Two fire engines and around ten firefighters attended a fire in a mixed-use block of offices and flats at Clarence Road in Deptford.
A small area in a ground-floor storage room of an office was damaged by fire and smoke. There were no injuries.
The Brigade's Fire Investigators believe the fire was accidental and was caused by the failure of a lithium-ion battery in a standalone portable CCTV unit.
A London Fire Brigade spokesperson said: "Batteries can present a fire risk when over-charged, short-circuited, submerged in water or if they are damaged.
"Avoid storing, using or charging batteries at very high or low temperatures and make sure they are properly protected when stored. It's really important to charge them safely too.”
The Brigade was called at 2156 and the fire was under control by 2238. Fire crews from Deptford and Greenwich fire stations were at the scene.
Firefighters' safety tips for using lithium batteries safely
Avoid storing, using or charging batteries at very high or low temperatures.
Protect batteries against being damaged – that's crushed, punctured or immersed in water.
Don’t leave items continuously on charge after the charge cycle is complete
When you travel, avoid keeping all your items containing lithium ion batteries together, especially on a plane. Check with your flight carrier for additional information or advice.