Have you checked each cell individually to check voltage levels? A single bad cell can cause issues. Not quite the same but I had a laptop battery that refused to charge so I opened it up and found a single cell had gone bad, changed it and the battery started working and charging.
This is not recommended for LiIon cells in any series-wired applications (as both laptops and the Cellink are done). The reason for this is that these cells are also charged in series, and any mismatching of actual cell capacity or wear characteristics will result in the one different cell being overcharged, over-discharged,, or both. That can lead to the cell "venting with flames" such as we've all seen pics of hoverboards doing
Not only are Lithium fires intense and hard to extinguish, this kind of event releases hydrogen flouride gasses, which breathing in only a small amount of can destroy your lungs permanently
In it's liquid form it gets absorbed through the skin into the bloodstream almost as completely and rapidly, again not something you want to experience at all. Those of us who are intimately familiar with the technology say that
the most important thing to know about LiIon is when not to breathe You most positively do not want such an event to occur in your car while driving in heavy traffic at speed. Nor do you want to encounter it when opening a previously closed car. Nasty stuff indeed.
LiIon cell replacement
can be done safely but it takes equipment which most of even LiIon enthusiasts like myself do not have to make sure the replacement cell matches the existing ones. Far better to replace all the cells with new matching ones, then use the old ones in other applications. Once again this needs cell tab-welding equipment which most do not have, but with a hot enough soldering iron, the right technique, and the right flux, these can be soldered in relative safety successfully.
Just know that too much heat or applying it too long will damage the cell or cause venting with flames so soldering is generally eschewed in lieu of buying or building your own tab welder. Even then you'd better know what you're doing
Those who might be interested in this need to do a lot of careful research on the inherent hazards of LiIon cells and batteries before you begin fooling around with them. No other common battery type can result in the dire consequences you can get when you exceed the recommended parameters of their care and use. If you have any doubts just let a professional do the work for you as a much safer option; most larger cities will have a shop that rebuilds tool batteries and they can usually handle all the other kinds too.
Phil
