Summary

Fireplace blower for the winter.

Rechargeable 18650 battery, 12V 50x50x20mm fan, boost converter to 12V.
What you need : Alu tube 22mm, 32mm, LiIon 18650 battery,
TP4056 charger mini size
See the black one here https://www.aliexpress.com/store/1965526?spm=a2g0o.detail.1000007.1.1e954c21HwVMem
SX1308 step-up converter
google "Mini DC-DC Boost Step Up Converter Voltage Regulator 3V 3.3V 3.7V 5V 9V to 12V" or https://www.ebay.com/itm/403045089203?hash=item5dd75bffb3:g:qwMAAOSwr2RfK9Kg,
switch DS-402 5mm, also Ebay.
The depicted LiIon charger PCB fits in the bottom plug. For bigger TP4056 PCB allow more tube length and connect it to a micro USB socket on PCB, this latter fits in the bottom plug. https://www.ebay.com/itm/322765469041?hash=item4b26523571:g:14YAAOSw~05Zwwty

The preferred step-up PCB must be set to 12V by solder patches. The one with potentiometer must be set to 12V, then desolder the pot and replace it with a resistor of approx. the same value, pot is too big to fit in.

No aluminium tube(s) : replace the 22mm tube with 3D print, for the thick blower tube salvage metal plate from a soda can and form a tube. This must be heat-resistant.

Two 3D prints, one for 50x50x20 mm fan (preferred) and 40x40x20 mm.