Overmold your electronics and charge the battery wireless.
We have made a form for silicone molding of the vibrator development board "body interaction". Now the LiPo batteries are charged wireless! And the electronic parts are sheltered by the silicone. We have used the Seeed Studio wireless charging module. Their are two coils, sender and receiver which are connected with a board named "IN" respectively "OUT". Just connect the power source of your development board with the wireless charging module "OUT". Mold everything. Now power the "IN" module and put them near the molded coil. Now your molded board will charge wireless.
Quickstart guide: https://projectbodyinteraction.files.wordpress.com/2015/09/quickstartguide-bodyinteraction1.pdf