A word of warning about leaving lithium batteries on charge when you go out, or even overnight. They can explode or burst into flame. Lithium batteries are compact, lightweight batteries that hold considerable charge and fare well under constant discharge-recharge conditions. The batteries are found everywhere -- in laptop computers, cameras, cell phones, and electric cars. Although accidents are rare, those that do occur may be spectacular, resulting in an explosion or fire. Here is a first hand account shared by Jonathan Poyner of a very scary incident involving a bike torch: I was sitting here looking at what's on Narooma Buy Swap Sell. Next to me was my daughters bike torch, on charge, when it burst into flames, sending a powerful 1m flame like a rocket across the room. Within seconds the house was full of toxic smoke from the li-ion battery and burning plastic.
The dressing table is burnt, but I was lucky enough to get the burning torch outside before things got out of control. The torch is a reputable brand that has only had 3 charges from its USB charger. My biggest concern was that I was just about to head out - which would have meant leaving my dog at home. Don't care about the house, but the dog couldn't be replaced. If anyone uses these modern batteries, be very careful leaving them on charge if you are not home.
Above: room filled with smoke House, clothes and bedding still stink of burning plastic. But my dog still smells like dog WARNING: Research laboratories and factories also use water to extinguish Li-ion battery fires. When encountering a fire with a lithium-metal battery, only use a Class D extinguisher as water reacts with the lithium metal and makes the fire worse