Instructions above were helpful for my HMDX Jam model HX-P230A. To replace the battery, I bought a 3.7V 550 mAh battery on eBay for $7.50. (I believe the original battery was 500 mAh). See eBay listing at http://www.ebay.com/itm/251453907013. There's no manufacturer but the UPC is 737590401657 and the Model number is 053035. I'm not a great solderer so I did not unsolder the old battery. Instead I clipped the leads about half way. I then twisted the new battery wires onto the wires dangling from the circuit board. BTW - the wires are really small. After twisting, I soldered the twisted wires and then wrapped with electrical tape. So far, works like new again. Good luck with your battery replacement!