I have a feature phone that's several years old, but still works fine. But the battery is on its last legs, and I'm having a problem replacing it. The battery is an Alcatel CAB3120000C1, which is 3.7V, 850 mah.
These batteries are all over Ebay, but a seller I contacted confirmed that the battery was discontinued several years ago, so the date code on all these OEM batteries is several years old, and they don't do very well anymore. The most recent one I've been able to find is the one I have, which is 2013. Most are 2010-2012. One seller offers non-OEM replacements, but didn't respond to my question about the age of his batteries.
I wondered if it might be possible to buy a *new* replacment cell, and put that into the battery, preserving all of the protection circuitry in the original. The battery is very thin - 4mm - and I don't know where to find a replacement cell that would work. The overall size is 40 x 50 x 4 mm.
I would hate to have to buy a new phone just because of the battery issue. Can anyone suggest a solution to this problem?