The manufacturer has provided eight AA batteries with a cell voltage of 1.5 V for the RC model remote control. These are connected in series to achieve a final voltage of 12 V. Having eight batteries or rechargeable batteries always in stock was too much and too expensive for me.
Instead, I redesigned the battery compartment and enlarged it. I used an 18650 Li-Ion battery that is charged via a TP4056 charge controller at a voltage of 5 V via a micro USB input. The voltage is raised to 12 V via a MT3608 DC-DC converter.