I had a very distinct feeling of "what-if" after seeing this. The thing is it very nearly happened to me. Yesterday. Basic story is that the charger on our Kawasaki drill died and both batteries were flat. So - why not charge them using a bench supply? It's an "18V" pack which could mean either 5 or 6 18650s. There are 6 bumps on the case so I guessed 6 cells. i.e. charge to about 24V. Set the supply to 24V & about 1.3A. After a while I heard sounds like the seals popping and the battery felt a bit too warm. Disconnected & measured the voltage as12V. Not good. Opened the pack and found that there were, in fact only 5 cells in series so the maximum voltage should be 21V. Let things cool off & it looks like I "got away with it", except for destroying the cells. Will look at repacking, once we replace the charger. (O/C main cap & fuse, S/c driver transistor - not really worth trying to fix). RP On 3 August 2018 at 09:29, smplx wrote: > > > On Thu, 2 Aug 2018, Richard Pope wrote: > > > James, Ryan, > > What has happened is a cascade failure. Remember that a battery is > > made of several cells. When one of these cells failed it overheated the > > cells around it. This caused these cells to fail and this overheated > > surrounding cells and so forth. The lithium in the batteries would reac= t > > in a violent manner to the oxygen in the air when the cells were > > breached. Once this type of failure starts there is no way to stop it. > > Actually, if I remember correctly, it's not the oxygen in the air that's > the problem but the composition of the electrolyte. Some chemistries are > happy to oxidise the lithium without the need for atmospheric oxygen. > > Regards > Sergio Masci > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .