Aporte original por: Josh Sebert ,
I was able to find battery replacement parts for them on ebay. It appears that the battery is soldered to the board inside so if you are comfortable soldering you should have no trouble. I couldnt locate a teardown guide on here but youtube has a video doing exactly this. https://www.youtube.com/watch?v=W_scZh_cfqE the parts on ebay were around $20. Good luck.