Camera batteries and charger, what's going on?

[ericmark]

I got some years back (likely 10 years ago) two batteries for my camera, and a USB charger, as when I inherited the camera I did not get the charger, so had 3 batteries and a double battery charger.

I found around 4 months ago, one battery would not charge, putting it to the charger the lights flashed on/off, then nothing, so thought well they have done well, no real complaints, then two days ago the other one of the two replacement batteries failed to charge, so I thought may be battery or maybe the charger, so got another pair of batteries and a charger.

So when it arrived tried old batteries in new charger, not problem, they charged, so tried new batteries in old charger, and no problem they charged, so now I have 5 batteries and two twin battery chargers, yes swapped batteries around again, and both sets charged.

So what is going on?

 

[flameport]

Old batteries discharged too far, old charger was particular about not charging batteries with a voltage that was too low.

New charger will charge any old thing regardless, old batteries on new charger are now charged above voltage level that old charger accepts, so now can be charged on both.

 

[ericmark]

So need to swap batteries more often in the camera.