There's a new, little-known way to bring virtually ANY dead battery back life again. I have actually already tried it with auto, laptop computer, and phone batteries that were entirely dead.
You can simply refurbish your old batteries and save a lot of money. https://wiki.snooze-hotelsoftware.de/index.php?title=3_Strategies_For_Battery_Reconditioning_Method_You_Can_Use_Today