Odd that nobody asked about polarity earier. You have to know this. Postive Tip or Negative Tip? Most are positive tip but there is the chance it is negative. I got this unit for 5 bucks so I am gonna try to charge the battery once I take it out and and or replace it. Then post what I find.

here is a good how to video https://digibron.wordpress.com/2012/11/0...-the-curse-of-the-black-spot-from-a-panasonic-lumix/