Hello, Yes, the lithium batteries can be not rechargeable if the become entierely discharged, you can see here a chart of the batteries technology and their self discharge rate Comparison of commercial battery types - Wikipedia Hope that answered your question
Hello, Looking at what you said, it seems like the issue is entierely due to the sd card, so you might wanna try to clone your sd card to another one, if it does’nt works, can you provide us more details (3ds model, sd card capacity etc…) Hope that helped !
Hello, As I can see, the pads are ripped but not too badly, so make sure the pins makes a great contact with the pads; you can also try to add a little wire (without the plastic shield) if you cant make a contact. Also to make sure the pads makes a great contact, you can try to clean them with IPA (Isopropyl Alcohol) and a Q-tip. Hope you can fix it !
Hello, PS4 controller are a mess to charge up as they need the right amperage (I think it’s 0.8amps but not sure) and also some cable don't works so try plugging in your console and/or try using different wall adapter and usb cables (preferably quality ones). If it still doesn't work, it might needs a repair (replacing the battery could works)