I wonder why they can't just INOP the battery chargers during flight until
they find the problem.
We can of course made innumerable suggestions for workarounds (more or less fanciful), for the case they suffer of such shortage. As it seems that the most oblivious one (the change of the battery type) is inapplicable, let's try also:
- Change the batteries after each flight with precharged and monitored/tested ones for at least ... days;
- After any battery kicks in, monitor the electronic bay /and land asap;
- Disable the charging circuit and install one.. /two..(as required) safe type batteries as stand by.... Eventually keep one on board and connect in really need only (If these bateries are indeed safe enough to be 'transported' in an aircraft and not to sensitive to fly (position, pressure variations, atmosphere, ..... not only temperature)
After all, the main battery is only for emergencies, and the APU usage can be temporarily limited through instructions