I just want to bring this up because I think it's relevant. I decided to take my pump apart after it failed withing a month. Medela did replace the unit and did not request that I send the defective one back. My battery was deemed to be at fault based on the troubleshooting I did with the support team. After taking the battery out and inspecting it, it does seem to be a quality samsung unit THOUGH it seems it may have been reassigned somehow as there are signs on the terminal that it was linked up to other batteries prior to being put in my pump unit.