Batteries health from 95 to 23 in a few days

i got a "refurbished" thinkpad t480 from ebay and it came with what seemed like good batteries at first however, after just a couple days the battery health on the external battery has dropped from 100% to 89% and the internal went from 94% to a whopping 26%. even in battery saver mode the external died in under 2 hours and the internal lasted a couple minutes before shutting off without warning. I'm using manjaro linux but i don't see how that could take the batteries down this fast, is there anything i can do to fix this or do i need to just buy new ones.