Many hearing aid wearers, whom have varying levels of dexterity and vison impairment, have no other choice than to change their disposable batteries every few days. Not only is this a physical challenge for hearing aid wearers, it also leads to 1.4 billion disposable hearing aid batteries being discarded into landfills annually. ZPower manufactures the only system that makes both new and existing hearing aids rechargeable. ZPowers patented silver-zinc rechargeable battery technology offers nearly double the run time of competing technologies, allows for a full day of power in todays most advanced hearing aids, and take the place of an estimated 200 disposable batteries annually. It became apparent that ZPower batteries could revolutionize the hearing industry after finding that rechargeability was among the top features sought by hearing aid wearers. The challenge was to regulate the high battery voltage so ZPower could be used in hearing aids. ZPowers engineers were able to develop a series of 3-D printed custom battery doors that did just that. The doors convert hearing aids that use disposable batteries, to hearing aids that can be used with rechargeable ZPower batteries.