JLemon
5 year old buck +
Put in some Alkalines and run a test batch.
Buy a cheap multi-meter and check voltage at the moment you put them in camera.
Or buy new batch of Rechargables.
IMO, NiMh are a royal PITA. Very finicky how they are charged.
I bought 4 of the Cuddeback solar panels when they were first released. Every one had at least 1 bad battery. I ended up throwing all the Tenergy batteries away and buying Rayovac.