Chosen Solution
Nikon coolpix L830 started to place messages , card can not be read., i turn it off them On and it worked. Now the camera does not turn on with the batteries , I plug it to the power supply and that’s how it works.
batteries can be bad enough that they appear to be fully charged in the charger but have such a high internal resistance that the terminal voltage under load won’t run anything. If u really want to test it u must put a load across your DVM probes and connect to the output terminals.
