As I use batteries to power the various project around the house and garden I've accumulated a number of different batteries, mainly Lithium Ion ones at 3.7V.
I use some 18650 cells from an old laptop battery that comprise two cells wired in parallel and some mobile phone type batteries that are thin and light.
|Two 18650 cells in parallel housed in a 3D printed case|
|Galaxy S4 QI Charge pad|
I wondered if I could connect the output to a lithium Ion battery charger PCB, from China and stick the pad onto a battery, this would allow me to just place the battery on a QI pad to charge it up and even place the device using the battery on the pad to keep it powered/charging.
It was quite simple to remove the USB socket from the PCB and solder to the charge pad and connect to the battery.
|The battery, charge pad connected to the charger PCB|
|The QI pad folded around the battery|
After that I used some heat shrink tubing used for battery packs to hold it all together.
|Whole assembly going into the shrink tubing|
The final package can then be used to power the project.