RR_NDB
A battery or a System with them could (should) have means to warn when going below a given threshold. The circuit to perform it cost less than USD16.
Not just mishandling...
If someone wants to disconnect a battery incorrectly then it will still cause problems the quote actually goes on to say
In many cases, according to these people, internal battery safety systems kicked in as designed, preventing maintenance officials from recharging the affected batteries.
I was just pointing out that the large number of battery failures seemed to be due to mishandling. Perhaps there needs to be more protection against that as well but its not an airborne occurrence - its a line maintenance issue.