Something I'll be looking at on Monday and I'd appreciate advise. A proposal has been submitted for the installation of lockable cabinets within the warehouse for the charging of small (3.7v) lithium ion batteries that the warehouse operatives use for their headsets (i.e. like those found in various portable electrical equipment on sale today). Up to 60 batteries per cabinet will be charged at once if all charging ports are fully utilised. There are 3 cabinets adjacent to one another so a maximum of 180 batteries. The cabinets are of metal construction and are fitted with ventilation ports to the top and bottom. The batteries are valve-regulated so from my (limited) understanding will not release hydrogen / oxygen unless left to overcharge. The area of the warehouse will not be covered by a sprinkler but a fully automated fire detection system is in place. My initial thoughts (and as this is outside my area of experience / competence I will be asking someone else who is) are that there is very limited fire risk due to the style of batteries. A CO2 extinguisher will be installed in the area to enable the early fighting of fire should it ever happen. My only concern from a lay-perspective is the number of batteries in close proximity. I welcome your thoughts on this.

Thanks for the link, certainly shows the differences in effectiveness of the various types of extinguisher. A bit of googling suggests that the Pyromet extinguisher shown in the video would be most suitable for Lithium Ion batteries.