I always use a battery grip that hold two batteries. And I carry two spares. If one fails, the other one will keep going. I number all my batteries so if I suspect trouble I note it's number and deal with it later. When a battery starts to swell ...
I don't know where you are located but I have had success using independent repair shops with old digital cameras. Recently I had an Olympus C-7070 (2005 vintage 7.1MP) camera fixed when it would not power on. The power board failed. Cost to repa...
