Neverthelss, back to the topic:
A 3.7V 2800mA was built in the NOVA Pro from factory, but I decided to enhance the replacment up to a 4000mAh (hoping ONYX charge electronics can handle that).
As you can see on the pic (red circle) the main board of the device, has two different power supply methods.
1.) by three Soldering points
2.) by the plug socket.